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Fundamentals of Pharmacology for Veterinary Technicians Chapter 3 Figure 3-1 Copyright © 2011 Delmar, Cengage Learning 12 6 9 3 2 4 5 7 8 10 11 1 1. Right drug X 2. Right dose 3. Right time 4. Right route and technique 5. Right patient 6. Right documentation
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Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-1Copyright © 2011 Delmar, Cengage Learning

12

6

9 32

4578

1011 1

1. Right drug

X

2. Right dose 3. Right time

4. Right route and technique

5. Right patient 6. Right documentation

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-2ACopyright © 2011 Delmar, Cengage Learning

Toxicityrange

Peak Concentration

Toxic effects (minimum toxic

concentration or MTC)

Desired drug action (minimum effective

concentration or MEC)

Dru

g co

ncen

tratio

n in

pla

sma

TimeDuration of effect

Subtherapeuticrange

Therapeuticrange

Onset ofactionA

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-2BCopyright © 2011 Delmar, Cengage Learning

Toxicityrange MTC

MEC

Peak concentration

Dru

g co

ncen

tratio

n in

pla

sma

TimeB

Subtherapeuticrange

Duration of action

Therapeuticrange

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-3Copyright © 2011 Delmar, Cengage Learning

Intramuscular Subcutaneous

Intravenous

Intradermal

90° 45°

25°10°–15°

Epidermis

Dermis

SubcutaneoustissueMuscle

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-4Copyright © 2011 Delmar, Cengage Learning

Luer-Lok tip

Barrel Rubberstopper

Plunger

5-cc syringe separatedand together (A)

3-cc syringeseparated (B)

Plunger

Rubberstopper

FlangeFlange

Slip-locktip

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-5Copyright © 2011 Delmar, Cengage Learning

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-6ACopyright © 2011 Delmar, Cengage Learning

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-6BCopyright © 2011 Delmar, Cengage Learning

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-6CCopyright © 2011 Delmar, Cengage Learning

C

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-7ACopyright © 2011 Delmar, Cengage Learning

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-7BCopyright © 2011 Delmar, Cengage Learning

Lumen

Bevel Shaft

Point

PointLumen

Plastic sheath

Shaft Hilt Hub

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-8ACopyright © 2011 Delmar, Cengage Learning

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-8BCopyright © 2011 Delmar, Cengage Learning

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-8CCopyright © 2011 Delmar, Cengage Learning

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-9Copyright © 2011 Delmar, Cengage Learning

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-10Copyright © 2011 Delmar, Cengage Learning

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-11Copyright © 2011 Delmar, Cengage Learning

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-12Copyright © 2011 Delmar, Cengage Learning

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-13Copyright © 2011 Delmar, Cengage Learning

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-14Copyright © 2011 Delmar, Cengage Learning

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-15Copyright © 2011 Delmar, Cengage Learning

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-16Copyright © 2011 Delmar, Cengage Learning

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-17Copyright © 2011 Delmar, Cengage Learning

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-18Copyright © 2011 Delmar, Cengage Learning

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-19Copyright © 2011 Delmar, Cengage Learning

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-20Copyright © 2011 Delmar, Cengage Learning

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-21ACopyright © 2011 Delmar, Cengage Learning

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Figure 3-21BCopyright © 2011 Delmar, Cengage Learning

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Table 3-1Copyright © 2011 Delmar, Cengage Learning

Table 3-1 Parenteral Routes of Drug Administration

seluR lareneGetuoR

Intravenous (IV): within the vein

• rapid onset of action• higher initial body levels of drug• shorter duration of activity (need to be

redosed more frequently)• larger volumes can be given• irritating drugs or drugs that are painful via

other routes can be given IV (e.g., oxytet-racycline)

• increased risk of adverse effects (if drug given too rapidly, not sterile, or not prop-erly mixed)

• drug must be pure, sterile, and free of particles

• drug must be water soluble

Intramuscular (IM): within the muscle

• relatively rapid onset of action (generally about 30 minutes)

• rate of absorption depends on formulation (oil-based is slow, while water-based is fast)

• provides reliable blood levels• longer duration of action than IV (can dose

less frequently)• shorter duration of action versus oral

(generally)• absorption may be altered by vehicle pres-

ent in preparation• limited use for giving irritating solutions• convenient route in fractious animals

Subcutaneous (SQ, subQ, or SC): beneath the skin into the subdermis

• slower onset of action than IM• less reliable blood levels (similar to oral)• longer duration of action than IM (can be

given less frequently)• absorption may be altered by vehicle in

preparation• cannot use irritating solutions• generally used for giving larger volumes of

nonirritating, water-soluble solution

Intramammary: within the teat and udder sinuses

• fast and even distribution into mammary tissue

• particle size important (in nonlactating cows particle size is small to reduce udder irritation and provide prolonged drug retention)

• may contain thickening agents to modify rate of drug release

Intraperitoneal (IP): within the abdominal body cavity

• variable onset of action• variable blood levels• provides large surface area for drug

absorption• irritating solutions may cause peritonitis

• care must be taken so that the needle does not penetrate any organs; this could lead to peritonitis

• fi rst passes via portal system through liver, which could inactivate (or enhance) the drug’s action

Epidural/Subdural/Intrathecal: above the dura mater of the meninges, under the dura mater of the meninges, or into the subarachoid space of the meninges

• rapid onset of action localized to the cen-tral nervous system (CNS)

• used for diagnostic procedures and for administering some types of anesthetic agents

• disadvantages include potential for mis-performance resulting in spinal injection or drug moving cranially in the CNS

Intra-arterial (IA): within the artery

• used for treating a specifi c organ only, because very high drug levels are deliv-ered to a specifi c site

• may be accidental (e.g., given in carotid artery instead of jugular vein)

Intradermal (ID): within the skin

• injection given between dermis and epi-dermis

• very slow absorption• low blood levels obtained• used for local treatments or allergy testing

Intracardiac (IC): within the heart

• rapid drug levels attained because drug passes from heart to systemic circulation

• may be used in emergency situations

Intra-articular: within the joint

• injection given in the synovial space of joints

• sterile technique is critical• drug can be absorbed systemically

Intramedullary or Intraosseous (IO): within the medullary cavity of bone

• provides rapid blood levels• not commonly used and is painful• route of rapid fl uid administration in

smaller animals and birds• usually administered in the femur/humerus

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Table 3-2Copyright © 2011 Delmar, Cengage Learning

Table 3-2 Topical Drug Forms

Topical Drug Form Description

Aerosol Drug suspended in solvent and packaged under pressure

Cream Drug suspended in water–oil emulsion

Gel Drug suspended in semisolid or jelly-like substance

Liniment Drug suspended in oily, soapy, or alcohol-based substance applied with friction

Lotion Drug suspended in liquid for dabbing, brushing, or dripping on skin without friction

Ointment Drug suspended in semisolid, lipid-based preparation that melts at body temperature

Paste Drug suspended in semisolid preparation that retains its state at body temperature

Powder Drug suspended in powder for external lubrication or absorption

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Table 3-3Copyright © 2011 Delmar, Cengage Learning

Table 3-3 Local Routes of Drug Administration

Inhalation: inhaled into the respiratory system

• examples include gas-masking of animals, endotracheal administration of gas anesthe-sia, and nebulization of drugs

• establishes rapid blood levels because the alveoli of the lung provide a large surface area for absorption

• may be used for anesthesia, emergency procedures, and treatment of respiratory disease

Topical: applied on top of a surface

• topical routes of administration include skin, conjunctival, and subconjunctival

• used mainly in dermatology and ophthalmology

• may or may not be absorbed systemically• drug must fi rst dissolve and then penetrate

the skin by diffusion• good local effect• may be irritating• easy to administer• animal may chew/lick/rub off

Rectal • rectal drug absorption may be lower than with oral drugs due to small surface area or composition of the rectal formulation. Local irritation is possible with rectally adminis-tered drugs

Vaginal • vaginal drug delivery varies depending on drug formulation factors, vaginal physiology, age of the patient, and the phase of the estrous cycle of the patient

Transdermal • transdermal drugs may be mixed with a chemical to enhance skin penetration, which allows the drug to pass through the skin to the bloodstream

• transdermal drugs are delivered slowly and continuously for an extended period making plasma levels of a drug relatively constant; skin irritation is possible

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Table 3-4Copyright © 2011 Delmar, Cengage Learning

Table 3-4 Oral Route of Administration

stpecnoC lareneGetuoR

Oral (po) • most convenient route of administration for owner• slower onset of action• longer duration of activity• sometimes erratic and incomplete absorption because

drug is affected by gastric fl uids (acid)• absorption may be affected by gastrointestinal disease• relatively safe• drug must be able to get through gastrointestinal mucosa• drug need not be sterile• generally causes fewer adverse drug reactions• absorption in ruminants may be questionable with some

medications given orally

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Table 3-5Copyright © 2011 Delmar, Cengage Learning

Table 3-5 General Guidelines for Drug Administration (adapted from Pharmacological Aspects of Nursing Care

1. Enteric-coated tablets should not be administered with antacids, milk, or other alkaline substances, because enteric-coated agents require the acid environment of the stomach to be effective.

2. Enteric-coated tablets should not be crushed before administration; crushing will alter absorption.

3. Suspensions and emulsions must be thoroughly shaken immediately before use, because the separation that occurs after standing for a short period will alter the dose if used in the separated form.

4. Suspensions should never be administered IV. 5. Solutions administered parenterally or in the eye must be sterile to prevent

causing infection. 6. Solutions administered IV must be free of particulate matter that could serve as

an embolus. 7. Proper storage of solutions is very important to prevent contamination and

evaporation. 8. Skin integrity should be assessed for rashes or open areas before applying topical

medications, as these conditions will alter absorption time of the medication. 9. Transdermal therapeutic systems or patches allow drugs to pass through intact

skin and care should be taken when applying these to animals to prevent self-medication.

10. Proper disposal of transdermal patches is important to prevent their ingestion by animals or improper exposure to people.

Fundamentals of Pharmacology for Veterinary Technicians Chapter 3

Table 3-6Copyright © 2011 Delmar, Cengage Learning

Table 3-6 Causes of Drug Toxicity

Cause of Drug Toxicity

Example

Outright Overdose Dosing too frequently, dosing too high, administering too long

Relative Overdose Recommended dose was too much for this animal, due to

this individual animal, and improper route of administration

Side Effects Normal side effects associated with drug may occur at a higher level in this individual

Accidental Exposure Exposure of animal to drug that is absorbed through skin or inhalation or accidental ingestion

Interaction with Other Drugs

If drug A is highly protein bound and drug B is protein bound as well, the competition for protein binding will affect the amount of free drug (active drug) available to the animal

Incorrect Treatment Misdiagnosis: treatment causes toxicity levels of drug because the animal does not have the disease; for example, hormone replacement raises hormone levels above normal in healthy animal


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