KING ABDUL AZIZ UNIVERSITYFACULTY OF PHARMACY

PHARMACOLOGY & TOXICOLOGY DEPT.

CORROSIVES LAB No.. 1 Date: ………………

The main toxic effect of corrosives consists of a local action on the tissues with which

they come in contact. The local actions of various corrosives are much alike. The

differences between compounds are chiefly in the intensity of the action. Some of them

act mainly on the alimentary tract and to a very small extent on the skin. The degree of

injury depends more upon the strength of the acid or alkali than upon the absolute

quantity. A small quantity of a conc. acid does more damage than such larger quantities of

dilute acid.

Corrosion or direct destruction of the tissue occurs if the agent acts directly on the

protoplasm. Chemical corrosion usually consists of simple inflammation followed by a

layer of necrotic tissue.

(A)The tissue protein is converted into acid proteinate, while dissolves in the conc. acid.

(B)Haemoglobin is converted into dark acid haematin and is precipitated.

(C)The intense stimulation by acid causes reflex loss of vascular tone. In the alimentary

tract, the primary effect of corrosion by acids is perforation which may be delayed for

several weeks.

The secondary effect is destruction of the gastric glands and the tertiary effect is

starvation from constriction of the esophagus.

Death may result at any stage, but it occurs most frequently from shock or suffocation

due to intense swelling and edema of the throat structures.

N.B.

1

Organic acids such as phenol, oxalic acid, acetic acid and citric acids are weak

corrosives if compared with inorganic acids.

The area of contact is stained brown or black except in the case of nitric and picric

acids, which produce a yellow stain. Precipitated blood (coffee-ground material) is

frequently formed in the stomach.

Alkalis such as carbonates and bicarbonates does not produce corrosive effects in

equimolar concentrations to that of strong alkalis such as sodium, potassium or

ammonium hydroxide which are markedly corrosive in action. They dissolve protein

material, saponify lipids and extract water from tissues. Corroded areas are soft,

gelatinous and swollen.

I-POISONS ACTING LOCALLY

1- SULPHURIC ACID

Symptoms of Toxicity

A-Skin contact:

The local action on the skin may cause first, second or third degree of burns. The first

degree burns result in erythema and edema with hot, painful, red and swollen skin. In the

second degree burns, the damage is more severe, the edema is greater and vesicles and

bullae appear. Scars and depigmented area may result. Third degree burns are

characterized by sufficient damage to destroy the skin and to cause deep ulceration.

B-Ingestion:

When sulphuric acid is swallowed, there is intense pain in the GIT. The tongue swells

and vomitus is brown-coloured due to the blood and eroded tissues which it contains. The

secondary and tertiary effects result in emaciation, sunken eyes, ulcerated throat,

thickened lower portion of the esophagus and contracted stomach.

C-Inhalation:

Inhalation of acid fumes causes coughing, chocking and variable symptoms of

headache, dizziness and weakness followed by pulmonary edema with tightness in the

chest, air hunger and cyanosis. Haemoptysis and shortness of breath may continue for

several weeks.

D-Eye contact:

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Conjunctival edema and corneal destruction occur from even dilute acids in the eyes.

The symptoms are pain, tearing, and photophobia.

Treatment:

A . Skin-contact:

1. Remove acid by flooding with water for at least 15 minutes.

2. Do not use chemical antidotes. The heat liberated in the chemical reaction may

actually increase injury.

3. Treat damaged areas as for thermal burns.

B. Ingestion:

1. Do not use gastric lavage or emesis because of the risk of perforation.

2. Ingested acid must be diluted by drinking quantities of water, milk, or egg albumin.

3. Give morphine sulphate to relieve pain.

4. Treat asphyxia by maintaining an adequate airway.

5. Treat shock by transfusion and by the administration of 5% dextrose in saline.

6. If symptoms are severe and perforation of the stomach or esophagus is suspected,

don’t give any oral remedy.

7. Maintain nutrition by giving 400 g of carbohydrate IV daily.

8. Give prednisolone to reduce esophageal stricture formation.

D. Eye contact:

1. Dilute the acid by flooding affected area with quantities of water in shower or

fountain for at least 15 minutes. The eyelids must be held apart during washing.

2. Do not use chemical antidotes.

3. Eye burns require an immediate attention of an ophthalmologist. If an

ophthalmologist is not available, wash the eyes and apply sterile bandages without

any medication. Pain is relieved by the systemic administration of analgesics. Then

take the patient to an ophthalmologist.

3

EXPERIMENT I:

Effect of conc. Sulphuric Acid on the Mucosa of Isolated Stomach or Intestine:

Reagents:1-Conc. Sulphuric acid. 2- Dil. Sulphuric acid.

3- Normal saline. 4-50% sodium bicarbonate solution

Procedure:

1. Take four pieces of animal stomach or intestine (about 5cm length each)

and expose the mucosa.

2. Pour 1 ml of normal saline, 1ml of conc. H2SO4 & 1ml of dil. H2SO4 on the

mucosa of three pieces respectively.

3. During a period of 30 minutes observe changes on each mucosa and report

your observation.

4. Pour 2ml of 50% NaHCO3 on the mucosa of the fourth piece, then add 1ml

of conc. H2SO4 drop by drop. Observe changes and report your observation.

2- NITRIC ACID

Symptoms of Toxicity:

The symptoms of poisoning are similar to those produced by sulphuric acid, but the

skin and GIT are characteristically yellow. This color is due to a reaction between nitric

acid and protein to form xanthoproteic acid. At autopsy a yellow coloration of the GIT is

observed as well as corrosion, sloughing and ulceration.

Treatment:

Poisoning with nitric acid is treated exactly in the same way as sulphuric acid

poisoning, and the same measures should be taken to avoid perforation of the damaged

areas of the GIT.

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EXPERIMENT II

Effect of conc. Nitric Acid on the Mucosa of Isolated Stomach or Intestine:

Reagents:1-Conc. Nitric acid. 2-Dil. Nitric acid.

3-0.9% sodium chloride 4-50% sodium bicarbonate solution.

Procedure:

Repeat steps 1-4 in Experiment I using conc., and dil.nitric acid in the place of conc. and

dil. sulphuric acid & report your observation.

3- HYDROCHLORIC ACID

Symptoms of Toxicity:

The symptoms of poisoning are similar to those produced by sulphuric acid but the skin

and GIT are characteristically white. The corrosion action is similar to but not as severe as

those produced by nitric or sulphuric acid.

Treatment:

Poisoning by hydrochloric acid is treated in the same way as poisoning by sulphuric or

nitric acid.

EXPERIMENT III

Effect of conc. Hydrochloric Acid on the Mucosa of Isolated Stomach or Intestine:

Reagents:

1-Conc. Hydrochloric acid. 2-dil. Hydrochloric acid.

3-0.9% sodium chloride 4-50% sodium bicarbonate solution.

Procedure:

Repeat steps 1-4 as described in Experiment I using conc., and dil. Hydrochloric acid in

the place of conc., and dil. sulphuric acid & report your observation.

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4- SODIUM HYDROXIDE

Symptoms of Toxicity:

1. Skin contact:

Alkalis penetrate the skin slowly. Extent of damage therefore depends on the duration

of contact.

2. Eye contact:

Sodium hydroxide causes conjunctival oedema and corneal destruction.

3. Ingestion:

Ingestion of Sodium hydroxide is followed by severe pain, vomiting, diarrhea and

collapse. The vomitus contains blood and desquamated mucous lining. Eroded areas are

white initially and then become brown and swollen. Symptoms also include rapid fall of

blood pressure, feeble and rapid pulse and rapid respiration.

Death may occur in three hours or it may be delayed for a year when stricture of the

esophagus occurs as a delayed effect. Pathological examination of the tissues shows

grayish-white, swollen and soft epithelium of the GIT. The mucous membrane of the

stomach may be brownish due to the formation of hemorrhagic foci and alkaline haematin.

Treatment:

A-Skin contact:

The skin is washed with running water until it is free of alkali.

B-Eye contact:

The eye is washed for 15 minutes with running water and then irrigated with normal

saline solution for 30-60 minutes. Sterile bandages are applied and pain is reduced by

administration of analgesic. The patient should be taken to an ophthalmologist.

C-Ingestion:

The alkali is diluted by giving water or milk to drink immediately and allowing vomiting

to occur.

Gastric lavage or emetics should be avoided.

Milk or olive oil should be given to smooth, the eroded areas.

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EXPERIMENT IV

Effect of Sodium Hydroxide on the Mucosa of Isolated Stomach or Intestine:

Reagents:1-Pellets of Sodium hydroxide. 2-Saline.

3-10% acetic acid. 4-Sodium bicarbonate powder.

Procedure:

1. Expose the mucosa of 4 pieces of animal stomach or intestine, each is 5cm length.

Each piece is washed with saline and placed in a small dish.

2- Reagents are added to the mucosa of the 4 pieces as follows:

1 ml of saline,2-3 pellets of Sodium hydroxide,2 ml of acetic acid + 2 pellets of

Sodium hydroxide then 1 gm of sodium bicarbonate.

3- Leave to react for 30 minutes and observe changes on the mucosa during this period.

Compare between the effect of Sodium hydroxide and that of sodium bicarbonate & report

your observations.

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II –POISONS ACTING LOCALLY & SYSTEMICALLYLAB No. 2 Date:…………………

1-PHENOL (CARBOLIC ACID)

Sources: Phenol is one of the oldest antiseptic agents. Currently phenol is used as disinfectant

and nail cauterizer.

Phenol also is a component (0.1-4.5%) of various lotions, ointments, gels, gargles,

lozenges and throat sprays.

Mechanism of action:

Phenol acts as a general protoplasmic (cytoplasmic) poison. Toxicity is due to its ability to

cause cell wall disruption, protein denaturation, coagulative necrosis (cell death

typically caused by ischemia or infarction), protein precipitation (astringent effect),

and corrosion with marble like appearance.

Symptoms of Toxicity:

A- Skin contact:

Blanching and brown stain occurs. Later anesthesia and necrosis occurs.

B-Ingestion:

Locally: Burning of the mouth and throat, white lips and mouth, nausea, vomiting and

abdominal pain.

If absorbed: Profuse sweating, diarrhea, cyanosis (from methaemoglobinaemia), hyper-

activity, hypertension, haemolysis, convulsions, coma and pulmonary oedema followed by

pneumonia.

Death: Convulsions of the diaphragm and eventually respiratory failure

Treatment:

A-Skin contact:

Washing with large amounts of water for at least 15 minutes. The washing is

followed by repeated application of castor oil, olive oil, glycerin, PEG (T.N=

Carbowax).

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B- Orally:

1. Delay absorption by raw egg or milk to act as protective covering on the mucous

membrane.

2. Administration of activated charcoal. Castor oil is given to dissolve phenol and retard

its absorptions.

3. Convulsions are controlled by administration of diazepam.

4. Methaemoglobinaemia is treated by IV injection of methylene blue.

5. Artificial respiration

6. Note: Avoid gastric lavage and emesis.

EXPERIMENT I

Effect of Phenol on the Mucosa of Isolated Intestine:

Reagents:

1-Phenol. 2-0.9% sodium chloride solution.

3-Castor oil.

Procedure:1. Take 3 pieces of animal intestine each is 5cm length and expose the mucosa.

2. Wash with 0.9% sodium chloride solution.

3. Apply (a) 1ml saline, (b) 1 ml phenol and (c) 1 ml castor oil with 1 ml phenol on the

mucosa of the 3 pieces respectively.

4. Observe changes during a period of 30 minutes and report your observation.

2 -MERCURIC CHLORIDE:Forms of Hg:

Elemental Hg: low absorption & low toxicity.

Mercurous Chloride (Hg2Cl2): inorganic salt, poorly absorbed & little toxicity.

Mercuric Chloride (HgCl2): inorganic salt, highly absorbed & high toxicity.

Organic Mercurials (methyl & ethyl mercury).

Source:

Acute ingestion of mercuric salts is usually intentional,

Mercurial diuretics.

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Mercury exposure from dental amalgams for both the dentist and patients.

Ingestion of pesticides, antiseptics and germicides.

Mechanism of action: 1- Locally: Protein precipitation & a general corrosive action to the mucosa.

2- Systemically: results from its affinity for essential cellular sulfhydryl groups, as it

binds to –SH group of S-containing amino acids (cysteine & cystine), results in the

inhibition of SH-containing enzymes.

Due to high concentration of non-protein sulfhydryl groups in renal tissues, accumulation

of mercury in the kidney may occurs.

Symptoms of Toxicity:

A-Skin contact: Skin inflammation, urtecaria & corrosion.

B-Ingestion: - Locally: gastroenteritis, grayish discoloration of mucous membranes, local

oropharyngeal pain, nausea, vomiting and diarrhea.

- If absorbed: shock and tubular necrosis with early development of oliguria.

Treatment:A-Skin contact: Wash with water for 15 min.

Put a demulcent like glycerin or castor oil.B-Ingestion: Lavage with protein containing solutions as milk or egg whites.

Use of activated charcoal

Bowel irrigation with polyethylene glycol solution may be useful in removing residual

mercury.

ANTIDOTE THERAPY: 1- Chelation: chelating agents themselves have thiol groups so they compete with

endogenous sulfhydryl groups for the binding of mercury and thereby prevent

inactivation of sulfhydryl-containing enzymes

2- Reduction: Na HCHO3 sulfoxylate reduces Hg2+ to Hg+ (low solubility & low toxicity).

3- Precipitation: CaS2 precipitates Hg2+ as HgS (not absorbed).

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EXPERIMENT II

Effect of HgCl 2 on the Mucosa of Isolated Intestine:

Reagents:

1-HgCl2. 2-0.9% sodium chloride solution.

Procedure:

1. Take 2 pieces of animal intestine each is 5cm length and expose the mucosa.

2. Wash with 0.9% sodium chloride solution.

3. Apply 1ml saline, or 1ml HgCl2 on the mucosa of the 2 pieces, respectively.

4. Observe changes during a period of 30 minutes and report your observation.

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III- POISONS ACTING SYSTEMICALLY1-ETHANOL (ALCOHOL):

Source: Beverages, solvents for perfumes, aftershaves & distilled spirits

Medicinal liquids including mouthwash & liniments

Antiseptics.

N.B. fatal dose is 300-400 ml of pure alcohol.

Mechanism of action:

Ethanol is a general CNS depressant. At low doses, it is a selective CNS depressant and

at high doses, it becomes a general depressant.

Ethanol depresses the CNS by dissolving in the cell's lipid membrane and disordering the

lipid matrix. (The membrane fluidization)

Symptoms of Toxicity:

A) Acute poisoning:

Increased sweating, mydriasis & blurred vision.

Muscle incoordination.

Slurry speech, decreased reflexes & occasional antisocial behavior.

Slowing of respiration, tachycardia.

Finally death due to respiratory depression.

B) Chronic poisoning (Alcoholism): Flushed faces (hyperemia).

Gastroenteritis, anorexia, diarrhea, liver cirrhosis.

Optic atrophy, brain oedema & mental deteriorations.

Treatment: A) Acute poisoning:1- Gastric lavage & activated charcoal is advisable.

2- Artificial respiration.

3- Use alkalinizer as NaHCO3 since alcohol metabolism gives CO2 causing acidosis.

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4- Flumazenil, specific benzodiazepine antagonist, may aid in reversing the respiratory

depression associated with ethanol ingestion.

B) Chronic poisoning: (Alcoholism) Disulfiram: (Antabuse (

Used for the prophylactic treatment of chronic alcoholism= alcohol deterrent. which

inhibits the enzymatic oxidation of acetaldehyde to acetate; this will lead to unpleasant

symptoms of disulfiram-alcohol reaction including skin flushing, headache, nausea,

dyspnea, tachycardia, hypotension, fever, seizures, even death from cardiovascular

collapse.

EXPERIMENT III

Effect of ethanol on the Mucosa of Isolated Intestine:

Reagents:

1-Ethanol. 2-0.9% sodium chloride solution.

Procedure:

5. Take 2 pieces of animal intestine each is 5cm length and expose the mucosa.

6. Wash with 0.9% sodium chloride solution.

7. Apply 1ml saline, or 1ml Ethanol on the mucosa of the 2 pieces, respectively.

8. Observe changes during a period of 30 minutes and report your observation.

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III- POISONS ACTING SYSTEMICALLY( continued )

LAB. No. 3 Date:…………….

2-IodineSymptoms of toxicity: A-Skin exposure: hypersensitivity reaction, fever and skin eruption.

B-Ingestion: corrosive effects such as edema of the glottis, with asphyxia, aspiration

pneumonia, pulmonary edema and shock, vomiting and bloody diarrhea.

C-Inhalation Headache, dizziness, delirium, collapse and stupor, death due to circulatory

collapse. .

Treatment : mainly supportive1. Oxygen with assisted ventilation .

2. Treatment of anaphylactic shock.

3. Monitoring fluid and electrolyte balance.

A-After ingestion: Do not induce vomiting nor do gastric lavage.

Dialysis.

Saline diuresis.

B-Inhalation: Remove the victim from exposure site; supportive care should be given.

C-Skin exposure: Irrigate the skin thoroughly with saline or water and treat symptomatically.

D-Eye contact: Irrigate thoroughly with running water or saline for 15 minutes. Refer to an

ophthalmologist

3- Hydrogen peroxide Symptoms of toxicity: A-Skin exposure: paraesthesia, blistering and whitening. Solutions >10% may cause

burns. Bleaching of the skin usually resolved within a few hours.

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B-Ingestion: Vomiting (the vomitus may be frothy due to the liberation of oxygen - risk of

aspiration), haematemesis, burning throat and gastric distension (due to the release of

oxygen). Gastrointestinal bleeding and burns to the stomach and duodenum may occur.

C-Eye contact: Irritation with a burning sensation, conjunctival hyperemia, lacrimation

and severe pain which resolves within a few hours.

Treatment : mainly supportiveAfter Ingestion: Gastric decontamination is ineffective due to rapid dissociation of hydrogen peroxide.

If gastric distension is severe a fine bore gastric tube may be passed to aid the release

of gas

Patients with severe clinical effects require abdominal and chest X-rays. The

Trendelenburg positioning (head down, elevated foot of bed) should be avoided since this

may trap air in the apex of the right ventricle and cause obstruction of the blood flow.

4- Copper sulphate Mechanism of toxicityCopper can bind to the sulfhydryl groups of several enzymes, such as glucose-6-

phosphatase and glutathione reductase, thus interfering with their protection of cells from

free radical damage.

Treatment : mainly supportiveAfter ingestion: 1-Give milk or egg white.

2-Management includes emesis or gastric lavage, correction of fluid and electrolyte

imbalance .

3-Chelation therapy (Dimercaprol (BAL), sodium calcium edetate and penicillamine are all

effective in binding copper.

5- Potassium permanganate Symptoms of toxicity: A-Ingestion: Spontaneous emesis and diarrhea may occur, especially after large volume

ingestion.

B-Skin exposure: corrosive burns on the skin and mucous membranes, skin and mucous

membranes are often characteristically stained purple brown.

C-Eye contactEye exposure can cause corneal and conjunctival burns

D-Other

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Vaginal exposure (used as an abortifacient) can cause vaginal or cervical burns and

erosions.

Treatment : mainly supportiveAfter ingestion: 1-Do not induce emesis because of the risk of corrosive injury.

2-Activated charcoal and cathartics are not effective and are contraindicated.

6- Picric Acid Mechanism of toxicityIt exerts direct actions on the cerebrum and lower brain centers, consisting of stimulation

followed by depression.

A-Skin Contact: Symptoms include redness, itching, and pain. Picric acid may be

absorbed through the skin with possible systemic effects.

B-Inhalation: Symptoms include coughing, shortness of breath. Systemic poisoning can

cause headache, dizziness, nausea, vomiting, abdominal pain and diarrhea. Heavy

exposures can cause red blood cell destruction resulting in bloody urine.

C-Ingestion: Symptoms include nausea, vomiting and diarrhea.

Treatment : mainly supportiveAfter Ingestion: Do not induce vomiting.

Give large quantities of water

7- Formaldehyde Mechanism of toxicityFormaldehyde binds proteins and nucleic acids, forming adducts difficult to eliminate via

metabolism.

Sources of Exposure The general population may be exposed to formaldehyde through tobacco smoke,

automobile emissions, from materials used in buildings and home furnishings.

Symptoms of toxicity: A-Inhalation:Effects caused by high formaldehyde concentrations are pneumonia, dyspnoea,

bronchospasm, coughing of frothy fluid, respiratory depression. Death is due to

pulmonary edema, respiratory failure, or circulatory collapse.

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B-Skin exposure: Coagulative necrosis of the skin, dermatitis and hypersensitivity

Treatment : mainly supportiveIngestion: Give water or milk.

Vomiting may be induced with syrup of Ipecac. If elapsed time since ingestion of

formaldehyde is unknown or suspected to be greater than 30 minutes, do not induce

vomiting. Ipecac should not be administered to children under 6 months of age.

Warning: Ingestion of formaldehyde may result in sudden onset of seizures or loss of

consciousness. Syrup of Ipecac should be administered only if victims are alert.

8-Potassium dichromateAcute poisoningHexavalent chromium compounds are generally more toxic than trivalent chromium

compounds. Absorption through the skin, swallowing or inhalation may be fetal. It contains

chromium (VI), a known cancer hazard, allergen, corrosive, skin, eye and respiratory

irritant.

A-IngestionNausea, Vomiting, Abdominal pain, Burning sensation, Diarrhoea, Shock or collapse.

B-InhalationBurning sensation, Sore throat, Cough & Wheezing

Treatment : mainly supportiveA-Ingestion: Gastric lavage with magnesium hydroxide or another antacid might be useful in cases of

chromium ingestion.

Induction of vomiting is contraindicated.

B-Skin exposure

Topical ascorbic acid has been successfully used to prevent chromium dermatitis and

dermal burns.

EDTA ointment 10% might facilitate removal of chromate scabs.

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Experiment 1-Apply each of the previously studied poisons on the mucosa of the isolated intestine of

rabbit.

2-Observe changes during a period of 30 min.

3-Record your observation

4-Compare the changes with the piece of isolated intestine after application of 1 ml of

saline ( control)

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HEMOLYTIC AGENTS AND

CHEMICALS AFFECTING HEMOGLOBINLab. No. 4 Date :

…

Mechanism of hemolysis:

A number of substances can cause acute hemolytic reactions by a direct effect on red cell

membrane. These substances include saponin, phenylhydrazine, potassium chlorate,

arsine, acetone, ether, acids and alkalis. In chronic lead poisoning, the effect of lead on

red cell membrane renders the cells brittle and decreases osmotic fragility. Hypotonic

solutions e.g. sodium chloride solutions less than 0.9% cause hemolysis the degree of

which depends on hypotonicity. For example, 0.1% sodium chloride solution is more

hemolytic than 0.5% solution.

Many drugs with oxidative potential can cause hemolysis in individuals with glucose-6-

phosphate dehydrogenase deficiency. These drugs include phenacetin, sulphonamides,

dapsone, aminosalicylic acid and primaquine.

Occasionally drugs produce hemolysis by an antibody-mediated mechanism. Such drugs

act as haptens and stimulate the production of antibodies. In two instances (penicillin and

cephalosporin) metabolites of the drug bind firmly to the red cells, destruction of which is

then brought about by the reaction of antibody with the cell-bound hapten.

Favism is a condition of hemolytic anemia caused by the ingestion of beans (Vicia faba) in

people with glucose-6-phosphate dehydrogenase deficiency.

Hemoglobin abnormalities

1. Carboxyhemoglobin:

Carbon monoxide binds to hemoglobin 200 times more strongly than does oxygen.

Therefore, in the presence of carbon monoxide, carboxyhemoglobin (HbCO) is

preferentially formed. Carboxyhemoglobin is cherry red especially in dilute solution.

2. Alkaline and acidic Hematins:

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In strongly basic or strongly acidic solution, hemoglobin is denatured to alkaline hematin

or acid hematin, respectively (the color is changed to brown).

3. Methemoglobin:

Methemoglobin is formed by oxidation of the ferrous (Fe2+) iron of hemoglobin to the ferric

(Fe3+) form by the action of a number of chemicals including nitrites, chlorates and amino

and nitro organic compounds. For example, sodium nitrite is used in meat curing, it may

be present in excess in home-cured meat, or the meat-curing salt may be used

accidentally as table salt. In infants or children, nitrates in well water contaminated from

agricultural use of fertilizers may be reduced to nitrites in the intestine and absorbed to

cause methemoglobinaemia. Organic nitrates and nitrites, including nitroglycerin, amyl

nitrite and other vasodilating nitrates are all capable of causing methemoglobinaemia.

Acetanilide, phenacetin, aniline, nitrobenzene and other nitro and amino organic

compounds are also powerful methemoglobin formers.

The ferric iron of methemoglobin can be reduced to ferrous iron (hemoglobin) most

promptly by the administration of methylene blue. After administration, the colored

methylene blue is rapidly converted to a leuko base by the coenzyme diphosphopyridine

nucleotide (DPN). This leuko base rapidly reduces ferric iron (Fe3+) to ferrous iron (Fe2+) .

Ascorbic acid is also capable of reducing the ferric iron of methemoglobin to the ferrous

iron of hemoglobin, but the action is slower than that of methylene blue.

4 .Sulphemoglobin:Sulphemoglobin can not carry respiratory oxygen. Sulphemoglobinaemia is

produced by the same drugs that cause methemoglobinaemia, in the presence

of in vivo (intestinal) hydrogen sulphide which completes the chemical reaction.

Sulphemoglobin is brown.

Diagnosis of its presence requires spectroscopy and chemical tests.

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EXPERIMENT I

Hemolytic effect of hypotonic solution:

Reagents:1-Distilled water. 2-1% sodium chloride solution.

3-10% sodium chloride solution. 4-Blood.

Procedure:1. Have two burettes, one containing 1% sodium chloride, and the other distilled

water.

2. Label a series of clean, dry test tubes, A, B, C, D, E and F.

a. In A place 4.5 ml NaCl solution +5.5 H2O to form 0.45% NaCl solution.

b. In B place 5 ml NaCl solution +5ml H2O to form 0.5% NaCl solution.

c. In C place 5.5ml NaCl solution +4.5 ml H2O to form 0.55% NaCl solution.

d. In D place 6 ml NaCl solution +4ml H2O to form 0.6% NaCl solution.

e. In E place 6.5 ml NaCl solution +3.5ml H2O to form 0.65% NaCl solution.

f. In F place 9 ml NaCl solution +1 ml H2O to form 0.9% NaCl solution.

3. In an additional tube, labeled G, place 10ml 10% NaCl solution.

4. To each tube add 6 drops of fresh blood, mix by inverting and allow the tubes to

stand for 5-10 minutes.

5. Report your observation.

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EXPERIMENT II

Effect of hypertonic solution:

Reagents:1-Distilled water 2-Saturated sodium chloride solution.

3-Blood

Procedure:1. In a tube place 10 ml hypertonic NaCl solution

2. To the tube add 3 drops of blood, mix by inverting and allow the tube to stand for 5-

10 minutes &.report your observation.

EXPERIMENT III

Hemolytic Effect of Ether:

Reagents:1-Pure ether. 2-0.9% sodium chloride solution.

3-Blood.

Procedure:

1. To 5 ml of 0.9% sodium chloride solution add few drops of ether and shake

vigorously.

2. Add 3 drops of blood, mix by inversion.

3. Add a few more drops of ether..

4. Report your observation.

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EXPERIMENT IV

Hemolytic Effect of Soap:

Reagents:1-10% soap solution in 0.9% sodium chloride solution.

2-0.9% sodium chloride solution. 3-Blood.

Procedure:1. To 10ml of 10% soap solution add 6 drops of blood. Mix by inversion.

2. In another tube place 10ml of 0.9% sodium chloride solution and add 6 drops of

blood. Mix by inversion.

3. Allow the tubes to stand for minutes.

4. Report your observation.

EXPERIMENT V

Formation of Acid Hematin:

Reagents:

1-Diluted blood. 2-Conc HCl

Procedure:

1. To 5 ml of the diluted blood add 5 drops of Conc HCl acid. The color

changes to faint red then to reddish brown (acid hematin).

2. Comment your observation.

EXPERIMENT VI

Formation of Alkaline Hematin:

Reagents:

1-Diluted blood . 2-0.1 N NaOH.

Procedure:

1. To 3 ml of the diluted blood add 2-3 drops of 0.1 N NaOH solution. The color

changes to brown (alkaline hematin).

2. Comment your observation.

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Report sheetEXPERIMENT I

Hemolytic effect of hypotonic solution:

Tube No. A B C D E F

Observation

Conclusion

Exp No Observation Comments

II

III

VI

V

VI

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POISONS AND THEIR ANTIDOTES

LAB No...5 Date :

Mechanisms of action of antidotes:

1- Chemical antidote:

a) Neutralizing agents: (no longer used)

Soap solution , lime water for acids.

Weak acids (citric, tartaric, acetic and lemon juice) for alkaline poisons.

b) Oxidizing agents:

Dil H2O2 and KMnO4 for alkaloids and glycosides.

c) Reducing agents:

Na formaldehyde sulphoxylate reduces HgCl2 into less toxic Hg2Cl2 (clomel, non

toxic) or metallic Hg (non toxic).

d) Precipitating agents: Tannic acids for alkaloids and heavy metals.

Iodine (lugol’s solution) for alkaloids and heavy metals.

Calcium glucontae for oxalic acid and NaF.

Sodium chloride for silver nitrate.

Dil. Sodium bicarbonate for ferrous carbonate.

e) Chelating agents: BAL (dimercaprol) for metals such lead, cadmium and iron.

Penicillamine for copper.

Deferroxamine (desferol) for iron.

f) Complexing agents: Starch for iodine poisoning.

2- Physical antidote:a)Adsorbants:

Kaolin, pectin…etc,

Fuller’s earth for paraquat (herbicide).

Cholestyramine for cardiac glycosides.

b)Demulcents:

Milk, egg white albumin, ice cream and gum acacia.

25

3- Physiological antidote:These are antidotes that counteract the effect of the poison by producing opposite

effects via acting on different type of receptors.

a) Adrenaline:

Adrenaline is the physiological antidote for histamine in anaphylactic shock. (Histamine

produces hypotension and bronchoconstriction through H1-receptor; adrenaline

reverses these actions through adrenergic receptors).

b) Potassium:

Potassium is the physiological antidote in case of digitalis toxicity.

4- Pharmacological antidote: These are antidotes that counteract the effect of the poison by acting on the same

receptors such as:

Atropine for pilocarpine.

Calcium for magnesium.

Naloxone for morphine.

5- Miscellaneous antidotes:a) Antidotes that interfere with lethal synthesis:

Ethanol in case of methyl alcohol poisoning ►methyl alcohol is converted in the body

by alcohol dehydrogenase into formaldehyde and then into formic acid causing

irreversible damage of the optic nerve and blindness.

Ethanol has more affinity to this enzyme than methanol and thus can stop the

formation of formic acid.

b) Antidotes that convert the poison into less toxic form:

Sodium thiosulphate used in the treatment of cyanide poisoning. It converts cyanide

into thiocyanate (less toxic and easily excreted).

26

Pharmacological antidotes to some poisons:

I-Physostigmine

Action: Anticholinesterases tertially amine that pass BBB.

Source: eye drops.

Symptoms:

Miosis, salivation, lacrimation, diarrhea, urination, bradycardia and

bronchoconstriction .Has an effect on CNS as initial excitation, convulsion, followed by

depression. Can cause unconsciousness & respiratory failure.

Antidote:

Atropine (parasympatholytic); competitive antagonist to Physostigmine at muscarinic

receptors.

Experiment: We need 2 mice (mouse 1 & mouse 2)

1. -Inject the calculated dose of atropine (dose:20mg/kg & concn :0.5%)

I.P. in mouse 12.After 30 min. inject the calculated dose of physostigmine

(dose:1.5mg/kg & concn :0.1%) in both mice.

3.Record onset time & duration of action & comment on the severity of

symptoms.

4.Compare between the two mice regarding the protective effect of

Atropine.

II-Magnesium

Action:

Magnesium is a calcium antagonist. Therefore, it impairs neuromuscular junction

transmission by decreasing acetylcholine release from presynaptic membrane. Mg

causes peripheral vasodilation, prolongs conduction through SA-node & AV-node and

increase AV nodal refractoriness.

Source:

In adults, Mg toxicity is rare especially in absence of renal failure since kidney excretes

Mg effectively.

27

The most common causes of toxicity are iatrogenic since Mg is commonly used to control

hypertension, pre-eclampsia, premature labor and to treat cardiac arrhythmias (Torsade de

Pointes) & myocardial infarction. Some laxative and antacid preparations contain Mg

Poisoning from Mg can result from ingestion (e.g., Epsom salts MgSO4) and from

occasional excess i.v. administration.

Toxic dose:

A patient with normal kidney function developed Mg toxicity (respiratory arrest,

bradycardia) after receiving 90 g of magnesium sulphate over 18 hours.

Symptoms:

Bradycardia, hypotension, muscle relaxation, respiratory arrest (apnea), CNS depression

and coma.

Treatment:

Gut decontamination: Mg may be eliminated by enema if it is in the bowel.

N.B. activated charcoal does not absorb Mg salts.

- Elimination enhancement:

Hemodialysis effectively removes Mg .If renal function is normal; i.v. furosemide (40

mg, adults) may be administered with replacement of urine volume by 0.90% saline.

Forced diuresis with mannitol (25 g by rapid i.v. infusion) may also be useful.

- Supportive measures:

Discontinue administration of Mg by all routes.

Artificial respiration.

Monitor serum electrolytes closely

- Antidote:

Calcium is an antagonist of magnesium action. Calcium may displace Mg from cell

membrane (Ca has 20 times higher affinity than Mg to their receptors)

Treatment with calcium is initiated when serum magnesium levels exceed 5 mEq/ L

and the patient exhibits symptoms.

The adult dose of calcium gluconate is 10 ml of 10% solution over several minutes.

28

Experiment: We need 2 mice (mouse 1 & mouse 2)

1. Inject the calculated dose of Calcium chloride I.P. in mouse 1.

2. After 30 min. inject the calculated dose of Magnesium chloride in both mice.

3. Record onset time & duration of action & comment on the severity of

symptoms.

4. Compare between the two mice regarding the protective effect of the

Calcium chloride, if no recovery, we may carry out artificial respiration.

III -Morphine

Action:

Narcotic analgesic producing physical & psychological dependence.

Source:

Morphine is an alkaloid derivative of opium which is obtained from the milky exudates of

incised unripe seed capsules of the poppy plant, Papaver somniferum.

Toxic dose:

The toxic dosage in a nontolerant adult is 30 mg parenterally or 40-60 mg orally. An oral

lethal dose in an adult is around 120 mg.

Symptoms:

-Acute toxicity: Morphine triad “pinpoint pupils, respiratory depression and coma”

- Other symptoms include nodding appearance, sedation, constipation,

bronchoconstriction due to histamine liberation, immunosuppression.

Treatment: 1) Acute poisoning:

- Gut decontamination.

- Elimination enhancement.

Dialysis procedures have not been used due to large volume of distribution.

- Supportive measures.

- Antidote:

Naloxone is the drug of Choice in morphine overdoses.

29

2) Chronic poisoning (addiction):

Methadone is given which is a morphine substitute with low withdrawal symptoms and

can be withdrawn gradually.

Experiment: We need 2 mice (mouse 1 & mouse 2)

1.Inject the calculated dose of Naloxone I.P. in mouse 1.

2.After 30 min. inject the calculated dose of Morphine in both mice

3.Record onset time & duration of action & comment on the severity of

symptoms.

4.Compare between the two mice regarding the protective effect of the

Naloxone

Diagnostic test for morphine :

“Straub-Hermann’s tail erection”; injection of morphine i.p. into a rat or mouse results in

tail erection due to contraction of anal sphincter.

IV -Neuromuscular blockers (Flaxedil)

Action:

Competitive antagonist to ACh at motor end plate.

●Source:

Mainly iatrogenic (NMBs are widely used in surgical operation) or idiosyncrasy e.g.

succinylcholine apnea in those patients with genetically deficient pseudocholinestrase.

Symptoms:

Prolonged skeletal muscle paralysis beginning with the small rapidly moving muscles of

the face & neck, then spreading to extremities and finally the diaphragm & intercostals

muscles.

Treatment:

-Supportive measures:

Artificial respiration in case of respiratory paralysis.

Anaphylaxis is managed with fluid support, antihistaminic, epinephrines.

30

-Antidote:

Neostigmine (anti-cholinesterase) with atropine (anti-muscarinic) to counteract the

peripheral muscarinic effects of Neostigmine.)

Experiment: We need 2 mice (mouse 1 & mouse 2)

1. Inject the calculated dose of Neostigmine protective mixture I.P. in mouse 1.

2. After 30 min. inject the calculated dose of Flaxedil in both mice.

3. Record onset time & duration of action & comment on the severity of symptoms.

4. Compare between the two mice regarding the protective effect of the injected

NMB agent and fill out the animal recording sheet.

.

V – Picrotoxin

Action: It is medullary stimulant.

●Source:

Picrotoxin a neutral principle obtained from the Cocculus indicus, which is the fruit of the

Anamirta paniculata. It is used in medicine externally as an antiparasitic. Internally it has

been used to check the night-sweats of phthisis. In large doses it is a powerful poison,

causing unconsciousness, delirium, convulsions, gastro-enteritis and stimulation of the

respiratory centre & may be death

Toxic dose:

LD 50 in rats is 5 mg/kg injected S.C

Symptoms:

In excessive doses this drugs produce clonic convulsions, which are characterized by

being:

a) Asymmetric i.e. the left side of the body convulses at different time from

the right one.

b) Coordinated i.e. when flexors contract the extensors are relaxed.

c) Spontaneous in origin i.e. the convulsions develop of their own & not in

response to external stimuli.

d) Intermitted i.e. not continuous.

31

Treatment:-Supportive measures:

Artificial respiration in case of respiratory paralysis.

Cardiovascular support by fluid administration.

Anaphylaxis is managed with fluid support, antihistaminic, epinephrines.

-Antidote:

Phenobarbitone as a CNS depressant which act as hypnotic will delay the onset of action

of symptoms of toxicity,

Experiment: We need 2 mice (mouse 1 & mouse 2)

5. Inject the calculated dose of Phenobarbitone (dose:180 mg/kg & concn :10 mg/ml) IP in mouse 1.

6. After 30 min. inject the calculated dose of picrotoxin (dose:20mg/kg &

concn :3.75 mg/ml) in both mice

7. Record onset time & duration of action & comment on the severity of

symptoms.

8. Compare between the two mice regarding the protective effect of the

injected antiepileptic agent.

32

KING ABDUL AZIZ UNIVERSITYFACULTY OF PHARMACYPHARMACOLOGY DEPT.

LAB No...5 Date: ..…………………

Animal recording Sheet

Animal provided: Sex of animal:Weight of the animal

Drug Antidode

Concentration

DoseTime of injection

Inject the both provided rat with Drug and Drug+ Antidode then fill the following table

Symptoms Drug Drug + antidode

Comment:

33

King Abdul-Aziz UniversityFaculty o Pharmacy

Dept. Of Pharmacology

FORENSIC CHEMISTRY

(QUALITATIVE TESTS FOR POISONS)

TOXICOLOGICAL ANALYSIS

34

Lab. No 6 Date..…………………: Collection, storage and use of specimens

Before starting an analysis it is important to obtain as much information about the

patient as possible (medical, social and occupational history, treatment given, and the

laboratory results or other investigations), as discussed in sections 2 and 3. It is also

important to be aware of the time that elapsed between ingestion or exposure of the

poison and the collection of samplers, since this may influence the interpretation of

results .

Specimen transport and storage

a) Specimens sent for analysis must be clearly labeled with the patient’s full name, the

date and time of collection and the nature of the specimen if this is not self-evident .

b) The date and time of receiving of all specimens by the laboratory should be recorded

and a unique identifying number assigned to each specimen .

c) Containers of volatile materials, such as organic solvents, should be packaged

separately from biological specimens to avoid the possibility of cross-contamination .

d) All biological specimens should be stored at 4oC prior to analysis, if possible, and

ideally any specimen remaining after the analysis should be kept at 4oC for 3-4 weeks in

case further analyses are required .

Samples required for toxicological analysis

1-Urine:

Urine is useful for screening tests as it is often available in large volumes and usually

contains higher concentrations of drugs or other poisons than blood. A 50-ml specimen

from an adult, collected in a sealed, sterile container, is sufficient for most purposes; no

preservative should be added. The sample should be obtained as soon as possible,

ideally before any drug therapy is initiated.

2-Stomach contents:

Stomach contents may include vomit, gastric aspirate and stomach washings – it is

important to obtain the first sample of washings, since later samples may be very dilute. A

35

volume of at least 20ml is required to carry out a wide range of tests; no preservative

should be added .

3-Scene residues

It is important that all bottles or other containers and other suspect materials found with or

near the patient (scene residues) are retained for analysis if necessary since they may be

related to the poisoning episode .

4-Blood:

Blood (plasma or serum) is normally reserved for quantitative assays but for some

poisons, such as carbon monoxide and cyanide, whole blood has to be used for

qualitative tests. For adults, a 10-ml sample should be collected in a heparinized tube on

admission .

5 -Faeces

The contents of the rectum are not often required for analysis, except in suspected heavy

metal poisoning, such as arsenic, mercury or lead. A sample of 20-30g should be taken

into a plain screw-topped jar or a plastic container with a snap-on lid.

6 -Liver and other organs

At autopsy, the most common organ to be saved for analysis is the liver, as it

concentrates many drugs, making them identifiable when the blood and urine

concentrations may have declined to very low levels. After cutting the organ to examine it,

the whole liver should be placed in a clean container.

7 -Hair and nail clippings

In the rare event of heavy metal poison being suspected, such as antimony, arsenic or

thallium, some hair cut or pulled at the roots, together with nail clippings should be

submitted for analysis .

Toxicological analysis of volatile poisons

36

Using a modification of Stass-Otto method many of the common poisons can be

separated into the following:

l. Volatile poisons:

Eg. ethyl alcohol, methyl alcohol, phenol, cyanide, chloroform, aniline.

ll. Non-volatile poisons:

A- Non-volatile acidic and neutral poisons:

Extracted with organic solvents as ether and chloroform in acidic medium

e.g. aspirin, salicylates, acetanilide, barbiturates and chlorpromazine.

B- Non-volatile basic poisons:

Extracted with organic solvents as ether and chloroform in alkaline medium

e.g. alkaloids such as atropine, quinine, strychnine and caffeine.

Procedure of isolation :

1. A tissue (intestine, liver or lung tissue) is provided in which is incorporated one or

more of the volatile poisons.

2. Cut the tissue into small pieces.

3. Cover it by a saturated solution of tartaric acid in a distillation flask and connect to

steam distillation apparatus (the set must be well closed)

4. Volatile poisons will distill in the first fractions and they are tested for by some

chemical tests.

Chemical tests for individual poisons :

37

Test for ethyl alcohol:

1 .Iodoform test:

-2 ml of Kl/I2 solution added to 1 ml of the distillate in a test tube.

-Mix well

-Add NaOH (10%) dropwise on the wall of test tube ------>faint yellow ppt or crystals

soluble in excess NaOH.

2 .Hanzlik's test (K2Cr2O7 in H2SO4): -Put 1 ml of distillate in a test tube & then add 1 ml of Hanzlik's reagent slowly, by means

of a pipette, under the alcoholic layer-------->bluish green ring is formed at the junction of

the two layers (without shaking).

Test for methyl alcohol : KMnO4 reduction test:

-Add 2 ml of distillate to 1 ml of KMnO4 (0.1%) then acidified with few drops conc. H2SO4

->— decolorization occurs at once.

Test for cyanide:

1 -Prussian blue test:- Alkalinize 3 ml of the distillate with NaOH then heat to concentrate to about 2ml

-Add 5 drops of FeSO4 (5%) followed by 2 drops of FeCI3 (10%).

-Warm gently over small flame.

-Add conc. HCI dropwise -----------> blue color will be formed.

2 -Picric acid test: -Alkalinize 1 or 2 ml of distillate with NaOH (till faint alkaline)

-Add 2-3 drops of picric acid& warm gently ----> red color will be developed

Test for phenol:

To 1 ml of distillate, add few drops of FeCl3 (10%) ----> violet color will be developed

38

Test for aniline:

Hypochlorite test:1 ml of distillate + 1-2 drops of sodium hypochlorite ----> violet blue color gradually

changing to brown or dirty red color.

Test for chloroform:

Coloration with -naphthol & NaOH:1 ml of distillate + 2-3 crystals of -naphthol + 2 ml NaOH (10%).

Boil in a water bath → blue to turquoise color in the upper aqueous layer fading gradually

to green.

39

KING ABDUL AZIZ UNIVERSITY

FACULTY OF PHARMACY

PHARMACOLOGY & TOXICOLOGY DEPT.LAB No. 6 Date.…………………… :

Student name: Student number( )

TOXICOLOGICAL ANALYSISScheme for volatile poisons:

Poison Name of Tests Results

1-Ethanol

2 -Methanol

3 -Cyanide

4 -Phenol

5 -Aniline

6 -Chloroform

TOXICOLOGICAL ANALYSIS

40

LAB No. 7 DATE………………

II- NON VOLATILE POISONSNON-VOLATILE ACIDIC & NEUTRAL POISONS : Procedure for extraction:The acidic residue of the previous experiment is to be extracted as follows:

1 .Extract twice with 10 ml portions of ether in a separating funnel.

2 .Extract twice with 10 ml portions of chloroform.

3 .Evaporate the combined organic extract on water bath (never use a flame in this experiment).

4 .Test in the resulting residue for non-volatile neutral and acidic poisons.

Chemical tests for individual poisons : Test for salicylates ; FeCl3 test:

-1 ml distillate + few drop FeCl3 (10 %) => violet color will develop.

Test for chlorpromazine (CPZ) : -Take 1 ml of distillate.

-Add 6 drops of Conc. H2S04 + one drop of FeCl3 => lilac color

Test for Phenobarbital:

Sodium Nitrite test:-1 ml distillate + 2 ml Conc.H2S04+ few crystals of Na nitrite => golden yellow color will

develop.

NON VOLATILE BASIC POISONS

41

Procedure for extraction:The aqueous solution remaining after previous extraction is treated as follows:

1 .Take 5 ml and make alkaline with ammonia.

2 .Extract twice with 5 ml portions of chloroform.

3 .Evaporate the combine organic extract to dryness in water bath (never use a flame in this experiment).

4 .Test in the resulting residue for non-volatile basic poisons.

Chemical tests for individual poisons

Test for strychnine-Put few mg of residue + 2-3 drops of Conc. H2S04 in a porcelain slap.

-Add few crystals of potassium dichromate (K2Cr2O7) —> blue violet rays will be formed

without shaking.

Test for atropineVitali's test

-Put few mg of residue + few drops of Conc. HNO3 in a porcelain dish.

-Evaporate to dryness

-Cool and dissolve in acetone and add few drops of alcoholic KOH -> light purple color

will be formed changing to red.

Test for quinine Fluorescent test

-dilute H2S04 dissolves quinine giving blue fluorescent solution.

Test for caffeine Murexide test

Put few mg of residue + few drops of Conc.HCL in a porcelain dish. Add 0.1 g potassium

chlorate (KCl04) and evaporate to dryness on water bath. Moisten the residue with few

drops of ammonia. The residue will acquire a purple color which disappears upon addition

of fixed alkalie (NaOH).

42

KING ABDUL AZIZ UNIVERSITYFACULTY OF PHARMACY

PHARMACOLOGY & TOXICOLOGY DEPT.

LAB No. 7 DATE..…………………:

Student name: Sample number( )

TOXICOLOGICAL ANALYSIS

A-Scheme for non-volatile acidic & neutral poisons :

Poison Tests Results

1-Tests for salicylates: -FeCl3 test:

2-Test for chlorpromazine (CPZ):

3 -Test for phenobarbitone: -Sodium nitrite test:

Conclusion: The poison(s) present may be ..……………………………… :

………………………………… …………………………………

43

KING ABDUL AZIZ UNIVERSITYFACULTY OF PHARMACY

PHARMACOLOGY & TOXICOLOGY DEPT.

LAB No. 7 DATE..………………………:

Student name: Sample number( )

TOXICOLOGICAL ANALYSIS

B- Scheme for non-volatile basic poisons :

Poison Tests Results

1-Test for strychnine:

2-Test for atropine: -Vitali’s test

3-Tests for quinine: -Fluorescent test:

4 -Tests for caffeine: -Murexide test

Conclusion: The poison(s) present may be …………………………………

………………………………… …………………………………

44

HYPOXIA

Lab. No. 8 Date…………………… :

Definition:

Hypoxia is a decrease in oxygen supply to the body, leading to decrease in energy supply

especially for brain and heart. If hypoxia exceeds two minutes, this will lead to irreversible

cerebral damage.

Utilization of oxygen by tissues:

During inspiration, air reaches alveoli at which the partial pressure of oxygen in air is

higher than that in blood, so passive diffusion of oxygen will occur from air to blood.

Oxygen in blood is carried by hemoglobin which is able to combine with oxygen in the

Fe2+ state to give oxyhemoglobin. Now the partial pressure of oxygen in blood is higher

than that in tissues, so oxygen is picked up by cells where the respiratory chain in

mitochondria produces energy.

Symptoms of hypoxia:

Due to decreased oxygen supply, the threshold at which different centers of brain are

functioning will decrease. If this level is very low, symptoms of hypoxia starts to appear:

Excitation in the form of tremors, convulsions, increased respiratory and heart rate. This is

followed by exhaustion and depression in the form of decreased respiratory and heart

rate, coma and finally death.

Causes of hypoxia:

Hypoxia may occur at different levels:

1. Defect in the air level due to reduced oxygen tension (concentration) in the air as in

case of high altitudes and badly aerated rooms.

2. Defect at the bronchi level due to obstruction in air airway passage as in case of:

a) Presence of mucous

b) Bronchoconstriction (histamine)

c) Corrosion of trachea

45

3. Defect in the mechanical process of respiration due to paralysis of respiratory

muscles (e.g. skeletal muscle relaxants like D-tubocurarine, and CNS depressants

like barbiturates and morphine).

4. Defect at the lung level due to pulmonary edema or pneumonia, the higher amount

of fluid will decrease surface area of alveoli leading to decrease in amount of air

exchanged, oxygen supply and decrease in amount of energy produced.

5. Defect in the oxygen-carrying capacity of blood due to:

a) Decrease in content of hemoglobin (as in case of anemia and hemorrhage).

b) Change in the nature of hemoglobin (as in case of Met-Hb, Sulf-Hb and Co-

Hb).

6. Tissue hypoxia or cytotoxic hypoxia due to defect in oxygen utilization by tissues

(as in case of cyanide poisoning in which cyanide combines with ferric ion,

cytochrome oxidase, so impairs its ability to carry oxygen.

7. Defect at glucose level (as in case of severe hypoglycemia) that is metabolic

hypoxia in which decrease in ATP energy production occurs.

Cyanide toxicity as an example of tissue hypoxia

Sources of cyanide:

Industry of rubber

Fertilizers

Crushed seeds of almonds and apricot

Mode of action:

Cyanide combines with cytochrome oxidase in the Fe3+ state, resulting in blocking its

ability to carry oxygen.

Symptoms:

Headache

Nausea, vomiting

Ataxia

Palpitation

46

Convulsions

Coma and death

Cyanide kits for prophylaxis:

Sodium nitrite or amyl nitrite is used in addition to sodium thiosulfate.

EXPERIMENT :

1. Record the normal characteristics of a mouse and inject it intraperitoneally with

potassium cyanide in a dose of 7.5 mg/kg (conc. 0.25 %).

2. Record the onset time and note the signs of toxicity especially respiration, size of

pupil, cyanosis and convulsions.

3. Inject another mouse with 20 mg/kg (conc. 1%) of sodium nitrite intraperitoneally,

after 30 minutes inject the specified dose of potassium cyanide intraperitoneally.

4. Record the survival time and comment on the results.

5. Inject another mouse with 20 mg/kg of sodium nitrite intraperitoneally, & 0.2ml 0f

sodium thiosulphate wait 30 minutes then inject the specified dose of potassium

cyanide intraperitoneally.

6. Record the survival time and comment on the results.

47

KING ABDUL AZIZ UNIVERSITYFACULTY OF PHARMACYPHARMACOLOGY DEPT.

LAB No.8 DATE……………………:

Animal recording Sheet

DrugAntidote

)Na Nitrite(

Antidote mixture )Na Nitrite+ Na

thiosulphate(

Animal providedSex of animal

Weight of the animal

Concentration

DoseTime of injection

Inject the both provided mice with Drug and Drug+ Antidode then fill the following table

DrugDrug + antidote

)Na Nitrite(

Drug +Antidote mixture

)Na Nitrite+ Na thiosulphate(

Symptoms &

observation

Comment:

48

King Abdul-Aziz UniversityFaculty o Pharmacy

Dept. Of Pharmacology

49

KING ABDUL AZIZ UNIVERSITYFACULTY OF PHARMACY

PHARMACOLOGY & TOXICOLOGY DEPT.

Case 1

Acetaminophen (Paracetamol)Date………………… :

A 16-year-old white female weighing 43 Kg had ingested 25 tablets of acetaminophen

each containing 500 mg. Four hours after the ingestion, she went to an emergency room.

She claimed to have taken her oral contraceptive pill that morning and denied recent

exposure to other drugs. This anxious patient denied any discomfort, nausea, vomiting or

right upper quadrant abdominal pain. Physical examination revealed a well-nourished

female in no apparent distress. Her vital signs were blood pressure 124/60 mmHg, pulse

112/min., and irregular respiration 16/min., and temperature 370C. Results of examination

of the head, eyes, ears, nose and throat were normal. The lungs were clear and the heart

was not enlarged. No murmur or gallops were detected upon auscultation, but the patient

appeared to have sinus tachycardia. Normal bowel sounds were heard in the abdominal

examination. The liver spanned approximately 8 cm and was mildly tender to palpitation.

Extremities were normal in appearance without petechiae or purpura. Cranial nerves were

grossly intact and no abnormal reflexes were elicited.

Questions : 1. Toxic doses of acetaminophen may cause the followings

50

a- Murmur

b- Hypertension

c- Tenderness of the liver

d- Tachycardia

2. The following are true regarding the toxicity of acetaminophena- Diaphoresis usually occurs after 24 hours of ingestion

b- Serum concentrations of hepatic enzymes begin to rise 24 hours after ingestion

c- Jaundice maybe noted 3 days after ingestion

d- Pericarditis maybe noted during the second phase of toxicity

3. Regarding the metabolism of acetaminophen, the following are truea- The majority of acetaminophen is conjugated with sulphate

b- A part amounting to 2% of the administered drug is metabolized by P-450 enzyme

system

c- Reactive metabolite forms hippuric acid when it reacts with Glutathione

d- With an acute toxic doses, the first agent to be depleted is glucuronic acid

4. Determination of prothrombin time in patients poisoned with acetaminophen shows a- No change

b- Only a little change

c- Elevated early and progressively

d- Slightly elevated and without significance

5. The reactive metabolite of acetaminophen reduces the amount of a- Glutamate transferase

b- Glutathione

c- Hepatic cytochromes

d- Methionine

6. The specific antidote for acetaminophen is a- Cortisone

b- Phenobarbitone

c- Glutathione

d- Cysteamine

e- Penicillamine

7. Precursors of glutathione includea- Cysteamine

51

b- Methionine

c- Cysteine

d- N-acetylcysteine

8. he following agents reduce acetaminophen-induced toxicitya- Barbiturates

b- Alcohol

c- Glutathione

d- Methionine

9. The following are true regarding assessment of the severity of acetaminophen toxicity

a- 2 g can induce hepatotoxicity

b- 10 g could cause hepatic coma

c- Hepatic coma is possible when the half-life of the drug exceeds 15 hours

d- Generally, hepatotoxicity maybe induced by acetaminophen when its half-life is 5

hours or more

10. Give the meaning of each of the following terms:a-Murmur b-Petechiae

c-Gallops d-Purpura

e-Auscultation f-Hepatic encephalopathy

g-Palpitation h-Pericarditis

i-Myocardial necrosis

Case 2

52

Salicylates

Date………………… :

A 10 –year old female developed symptoms of an upper respiratory tract infection

with a temperature of 38.4 ºC, nasal congestion and general malaise. The child's mother

began treatment with two adult aspirin tablets (325 mg each) every 4-6 hrs. In addition,

the child was given one Coricidin "D" (chlorpheniramine maleate, aspirin (325 mg),

phenyl-propanolamine HC1 tablet every 4-6 hrs for nasal congestion. On the following

day, the child developed abnormal breathing with nausea and vomiting. The patient's

mother administered bismuth subsalicylate 1 tablespoonful (130 mg) every 4-6 hrs, for the

nausea, and vomiting. The patient continued to receive these drugs regularly until the

day of admission. On examination by the family physician, the patient was noted to be

hyperthermic, tachypneic, lethargic and disoriented with regard to time and place.

Physical examination on admission revealed an ataxic, hyperpneic and disoriented child

with a rectal temperature of 40ºC In addition, convulsions; coma, hyperglycaemia

(followed by hypo-glycaemia) and metabolic acidosis have been reported. The clinical

course progressed to pulmonary oedema, haemorrhage, renal failure and oliguria.

Questions :

53

1 (Nomogram is used to estimate: a- Median lethal dose of aspirin

b- Toxic dose of aspirin

c- The severity of acute salicylate poisoning

d- Whether the toxicity is mild, moderate or severe

2 (Toxic effects of aspirin are produced when: a- a dose of 100 mg/kg is given

b- a dose of 150 mg/kg is given

c- a serum level of 60 mg/100 ml is monitored

d- a serum level of 30 mg/100 ml is monitored

3 (Respiratory alkalosis is induced by salicylates is due to

a- Increased accumulation of CO2

b- Increased accumulation of 02

c- Inhibition of Krebs cycle dehydrogenase

d- Uncoupling of oxidative phosphorylation .

4 (Uncoupling oxidative phosphorylation enhances the formation of

a- Oxaloacetic acid

b- Glutamic acid

c- Acetic acid

d- Lactic acid

5 (Severe disturbances in glucose metabolism induced by aspirin are due to a- increased blood insulin

b- increased release of insulin

c- inhibition of glycogenolysis

d- increased aerobic metabolism of glucose

6 (Toxic effects of aspirin are also seen in blood coagulation mechanism and consist of:

a- reduced plasma prothrombin

b- increased prothrombin time

c- stimulation of platelet aggregation

d- reducing the formation of TXA2

7 (Chronic salicylism:

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a- May occur at level of 70-90 mg%

b- The patient suffers from fever, dehydration, abnormal bleeding parameters .

c- Mortality rate is very low.

d- It mostly occurs in elderly people

8 (Rapid testing for salicylate presence can be done by: a-adding ammonium hydroxide to urine

b-adding ferric chloride to acidified & boiled urine.

c-phenistix reagent strip to urine.

d-adding sulfuric acid to urine.

9 (When patient with acute intoxication is first seen, what studies are essential in addition to serum salicylate?

a-Blood glucose.

b-CSF glucose

c-Blood & urine pH

d-Urine specific gravity.

10 (Gastric emptying: a-Should be attempted up to 12 hours postingestion.

b-Is not beneficial after 6 hours.

c-Is only effective in the first 4 hours

d-Is ineffective in treatment of salicylate intoxication

11 (The best technique for treating salicylate intoxication is: a-Hemodialysis

b-Gastric dialysis

c-Resin Hemoperfusion

d-Charcoal Hemoperfusion

Case 355

OPIATESDate………………… :

One- year-old boy is brought via ambulance to the ER in an unresponsive state. The

emergency medical technician who came with the child told the attending physician that

the child was only lethargic when he was initially reached by them, becoming

unresponsive shortly before arrival. His mother gives the history that he was playing with

his aunt's purse containing a bottle of propoxyphen hydrochloride capsules, 32mg each.

It is estimated that he took between 5 and 10 tablets. The ingestion is felt to have

occurred 30 minutes prior to arriving to ER.

Questions : (1Which of the following is the correct early management of this case:

a-1.Lavage with mineral or olive oil.

2.Give analeptic drug.

3.Maintaine airway.

b-1.Establish airway by artificial respiration.

2 .Evaluate vital signs and neurologic status as rapid as possible.

3.Give antidote.

c-1. Do a careful neurologic examination.

2 .Maintain stable vital signs .

3 .Establish airway.

d-1.Establish airway.

2 .Quickly evaluate status of patient including vital signs.

3.Give analeptic drug.

2)The specific drug to counteract effects is :

a-Naloxone

b-Caffeine sodium benzoate

c-Methadone

d-Amphetamine

3) There was a good response to this; however, it was felt necessary to empty the

stomach. For this child, this was accomplished:

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a-Mineral or olive lavage

b-Normal saline followed by activated charcoal

c-Normal saline only

d-Sodium sulphate solution

This procedure was accomplished successfully and child was admitted to the ICU

and continued to the antidote apprpiatly

4) It was noted that he should be carefully observed and followed for:

a-Renal failure

b-Convulsions

c-Pulmonary edema

d-Hyperglycemia

5) The patient continued stable and it was felt that the antagonist was no longer needed.

The other therapy used was:

a-Alkalinaztion of urine

b-Forced diuresis

c-Dialysis

d-Symptomatic only

By 24h after ingestion, the child was alert and able to feed himself with his own

bottle. Recovery was felt to be complete and rapid. Hospitalized remained

hospitalized one more day. It was discovered at tjis time that the child's aunt was

pregnant. She was advised not to take this drug?

6)Why should she not to take this drug:

a-Newborn infants experience withdrawal syndrome

b-Newborn have a high risk of hyperbilirubinemia

c-It increases chance of premature birth

d-It may be teratogenic

7) Irregular breathing produced by toxic doses of opiods may be related to:

a-Decrease in responsiveness of respiratory centers to CO2

b- Increase in responsiveness of respiratory centers to CO2

c- Stimulation of the medullary centers.

d- Inhibition of the medullary centers

8) The following are among Pharmacological actions of narcotic analgesics:

a-Increasing propulsive movement of intestine

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b-Decreasing the vagal activity of GIT

c-Increasing the resting tone of the smooth muscle of the large intestine

9) Narcotic detoxification can be produced by the following :

a-Methadone

b-Naloxone

c-LAAM

d-Physostigmine

10) The following disorders are among complications of narcotic analgesics toxicity:

a-Nephrotic syndrome

b-Viral hepatitis A

c-Viral hepatitis B

d-Intestinal bleeding

Case 4

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DIGOXINDate………………… :

A 20-month-old child weighing 11.4 Kg was found by his grandmother with an open bottle

of her “heart medicine”. There were no tablets in his mouth at the time, although several

tablets were moist, and many were spread around the room. The heart pills were

identified as digoxin, 0.25 mg.

Approximately one hour later, the child became sick and vomited several times. The

grandmother at this time mentioned the events to the parents who had not been home

when the accident occurred. They phoned the Poison Control Center to determine the

relationship between the illness of the child and events of the previous hour. The parents

were instructed to use syrup of ipecac and were told to bring the child to the emergency

room.

Physical examination on arrival at the emergency room revealed a well-developed child

who was having dry vomiting and who was pale but alert. His vital signs were blood

pressure 98/54 mmHg, pulse 60/min. and irregular respiration 28/min. and temperature

370C. Upon examination, the head, eyes, ears, mouth, nose, neck and chest were all

normal.

An ECG showed first degree AV block and occasional supraventricular extrasystole. The

abdominal examination showed a soft abdomen with active bowel sounds and no

organomegaly. Skin, joints were all normal with no petechiae, ecchymoses, and rashes or

swelling. The neurology evaluation showed slight decreased deep tendon reflexes. The

chest X-ray examination, urine analysis and hematological values were all within normal

limits. The initial digoxin blood level was reported as 12µg/ml taken at 3.5 hours after

ingestion.

Questions:

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1) The early symptoms of digoxin intoxication area. Persistent nausea and vomiting

b. Anorexia

c. Convulsions

d. Drowsiness especially in children

e. Abdominal colic

2) Drug management of the digoxin poisoned patient depends on the arrhythmia present so that various regimens of drug are necessary. The following are the most useful

a. Phenytoin

b. Quinidine

c. Procainamide

d. Lidocaine

3) The electrolyte used to prevent arrhythmia is a. Calcium

b. Sodium

c. Potassium

d. Magnesium

4) Other treatment which may be necessary a. Diazepam for CNS effects

b. Hemodialysis

c. Diuretics

d. Antiemetics

5) Mechanisms of digoxin-induced toxicity include a. Inhibition of vagal nerve activity

b. Inhibition of Na+-K+ ATPase pump

c. Stimulation of CTZ

d. Stimulation of heat regulatory center

6) The reported lethal dose for adultsa. 70µg/ml

b. 80µg/ml

c. 15 mg/kg

d. None of these

7) The following are true regarding the treatment of digoxin toxicity

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a. Glucose and insulin are given to decrease extracellular level of potassium

b. Digitalis-specific antibodies are useful in overcoming poisoning

c. Phenytoin sodium is given at a dose of 40 mg I.V.

d. Atropine sulphate reverses the increased vagal tone on the S-A node and to

correct sinus rhythm

8) Overdosages of digoxin may cause the following electrolyte imbalancea. Alkalosis

b. Hypomagnesaemia

c. Hyponatremia

d. Hyperkalemia

9) The following symptoms are not included among those produced by digoxin toxicity

a. Hypertension

b. Visual disturbances

c. Loss of appetite

d. Skin rash

10)Give the meaning of each of the following termsa- Organomegaly e- Anorexia

b- Petechiae f- Amblyopia

c- Ecchymoses g- Blurred vision

d- Delirium

Case 561

CYANIDEDate………………… :

Wilfred S. was brought to the ER of his community hospital by his coworkers with the

history of having approximately ten minutes earlier drunk a glass of cold water from a

several-quart, large-mouth glass jar which had been in the refrigerator of a house that his

exterminating firm had just fumigated within the last 24 hours with hydrogen cyanide gas.

The house had just been opened and the gas-tight envelope was just being removed

when he entered the house wearing his protective mask and brought from the house the

jar of cold water. He took it outside of the house, removed his mask and poured a glass of

cold water. A colleague was about to drink some of the same water when the patient

warned him that the water “had a funny burning taste”. This associate tasted the water on

the tip of the tongue and agreed. As he was doing this, the patient said, “Take me to

hospital” as he suddenly collapsed into unconsciousness. The time had been 3 to 5

minutes. The hospital was 5 minutes away, but the treating physician was immediately

available upon arrival. The patient was unresponsive with shallow, irregular, grasping

respirations with a bradycardic pulse of poor quality and blood pressure of 100/50. There

was cyanosis.

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Questions:1. The mechanism of action of the cyanide ion resulting in toxicity is due to its

a-reaction with the ferrocholinate in the mitochondria

b-reaction with ferric ion of the cytochrome oxidase in mitochondria

c-reaction with the ferrous ion of the cytochrome oxidase in mitochondria

d-reaction with acetylcholine at the chemoreceptor cells

2. At low concentrations cyanide directly a-depresses the respiratory center at the level of pons

b-stimulates the chemoreceptor sod the medullary respiratory center

c-blocks oxidative metabolism of the chemoreceptors of the aortic and carotid

bodies

d-inhibits the glycolytic pathway

3. The following are truea-the cyanide ion is easily absorbed by inhalation or ingestion resulting in severe

toxicity and death in minutes to three hours

b-cyanide cannot be absorbed through the skin

c-there are no natural mechanisms for the body to detoxify or to excrete cyanide

d-little is known regarding lethal dose and almost any dose can be fatal

4. The immediate recognition of cyanide poisoning is crucial since thaerapy must be started immediately. The patient realized what had happened because a-Hydrocyanic acid in concentrations as low as 1 ppm emits a characteristic odor

of bitter almonds or macaroons

b-The odor is that of garlic

c-The taste of the acid and the sodium and potassium salts is that of garlic

d-Only the odor is characteristic

This recognition probably saved the life of the patient's colleague. It certainly alerted the

patient.Because cyanide is one of the most rapidly acting and toxic of all poisons,

immediate therapy is essential. The co-worker mentions that a cyanide antidote kit is in a

truck still located at the house. He is sent to bring this to the hospital as the appropriate

antidote is not available at this small hospital.

5. In the interim the treatment is

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a-Lavage b-nothing is possible

c-Dopamine d-100% oxygen

The patient was given this therapy, although his respirations worsened and he became

more cyanotic. Positive pressure oxygen was necessary.

6. He was put on a cardiac monitor which revealed a-lengthening of QT interval b-pronounced ST elevation

c-abnormal QRS d-depressed T wave

The specific antidote is delivered. The time between ingestion and arrival is now 30

minutes.

7. The kit was sealed with a wire and marked for physician use only. It contains a-spirits of ammonia b-amyl nitrite

c-sodium thiosulfate d-metaraminal

e-sodium nitrite

8. Other antidotes if the kit was unavailable to slow toxicity area-activated charcoal b-none for PO or inhalation route

c-aluminium hydroxide PO to slow absorption d-oral nitrates

The kit was immediately opened and amyl nitrite inhalation under the oxygen mask was

given while the sodium nitrite was put into the springs 10 cc of a 3% solution over 3

minutes, followed by 50 cc of a 25% aqueous solution of sodium thiosulfate, over 10

minutes. After it was given IV, there was definite improvement in the patient's cyanosis yet

he was not breathing spontaneously. BP 50/30. Inhalation nitrite was continued as was

oxygen and positive pressure.

9. The therapy results in a-high concentration of methemoglobin

b-competition between CN and cytochrome

c-dissociation of cytochrome

d-production of complex which will transport oxygen

10. This results ina-combination with cyanide complex

b-removal of ion preventing the formation of the toxic complex

c-competition with cytochrome oxidase for cyanide ion

d-decomposition of methemoglobin

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11. In addition to removal of cyanide by the lungs and some trapping mechanisms ,the body has one other natural mechanism for removal or detoxification

a-combination with glutathione b-reaction with rhodanese

c-reaction with glucokinase d-reaction with succinylcholase

12.This nontoxic substance is a-readily excreted by the urine b-excreted through the bile

c-slowly excreted in the urine d-exhaled

Following the use of the three antidotes, there was definite improvement in his color, but

there were no spontaneous respiration and BP was 50/30. There was no change in EKG

and pulse continued weak. Oxygen was continued at 100% under pressure. Twenty

minutes after specific antidote he developed spontaneous respirations with rise in BP and

pulse. He continued to have the bluish color of methemoglobin. Additional thiosulfate was

given as well as one unit of whole blood. Following this, he responded to stimuli and had

normal papillary reaction. He continued cyanotic however, this was expected in view of

the methomglobinemia. A repeat dose of 10 cc sodium nitrite 3% and thiosulfate is given

slowly over 10 minutes.

13. The question of the danger of methemoglobin is raised. A local Poison Control Center was called as the patient had been receiving 50 cc of a 25% sodium thiosulfate given slowly. They responded that

a-10 cc of the nitrite is too much of a second dose

b-methomglobinemia cannot be detected by skin color until 30%, although

symptoms do not occur until 65%

c-follow the methemoglobin levels, keeping the level below 50%

d-since cyanosis from methemoglobin of 15% is readily obvious, only way to

judge therapy is blood assay

e-hemoglobin can be released spontaneously over a period of hours – do not

worry

14. If methemoglobin exceeds toxic level the antidote is a-ascorbic acid b-100% oxygen only

c- methylene blue d- packed red cells only

15.The nitrites may also result in a- profound fall in blood pressure b- anuria

c- hypertension d-convulsion

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16.The best treatment isa-furosemide b-paraldehyde

c- apresoline d-epinephrine or its cogenors

17.100% oxygen was used throughout treatment period. The role of oxygen in cyanide poisoning is

a-only effective at hyperbaric pressures

b-only effective as it potentiates the effects of the thiosulfate or nitrite-thiosulfate

combination

c-primarily protective for excessive methemoglobin production

d-not important

This was used with good results following the second dose of antidotes. After five hours of

stability of vital signs yet poor responsivenessand continued therapy, he suddenly

developed periods of apnea with irregular respirations and hypertension. The diagnosis of

acute pulmonary edema was made and therapy with diuretics, aminophylline, and

Cedilanid was started. With this treatment, his chest improved within 90 minutes. Over the

next several hours he became hypotensive, febrile, flaccid and required respiratative

measures. Despite appropriate supportive therapy with excellent response to aramine and

diuretics, his heart weakened and he was pronounced dead 28 hours after ingestion.

Despite the widespread belief that the ingestion of cyanide is invariably fatal, as long as

the heart beats the specific therapy is almost always effective. Although most cases of

cyanide poisonings are cases of suicides, work-related accidents can occur. Rarely are

children involved

18. The following is truea-The dose of sodium nitrite appropriate is less for children, as lethal

methomglobinemia may result

b-Methylene blue is always indicated

c-Exchange transfusion is treatment of choice

d-The treatment is the same

19. Sources of cyanide for children in the home cana-photograph developers b-instant adhesives

c-plants, especially while cherry seeds, hydrangea, apricot pits and chokecherry

d-rodenticides e-silver polishes

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20.A new antidote which can be used with thiosulfate to replace the nitrite is a-puruvic-cyanohydrin b-o-aminopropiophenone

c-cobalt nitrite d-hydroxycobalamine

21. It functions by a-producing methomoglobin more rapidly

b-combines with cyanide to form vitamin B12

c-stimulates the rhodanese enzyme

d-forms a complex readily oxidized by CO2

22. Which are true?a-chronic poisoning does not occur

b-pulmonary edema can result from chronic exposure

c-pathologically demyelinization in the brain results

d-changes in brain metabolites results

e-changes in brain metabolites result, with decreases in oxidative metabolism

and glycolsis

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