Principles of Surgical Pharmacology

ST210Concorde Career College

Principles of Surgical Pharmacology

History of Pharmacology

Objectives:

• Define the term pharmacology

• Provide a timeline of the events leading up to modern pharmacologic practice

• Perform basic mathematical calculations to allow conversion between the various measurement systems and correct drug dosages

Definition

Pharmacology = the study or science of drugs

Root derived from Greek terms farmakon (drug) and logy (science or study of)

Definition

• Drug – Substance used as

medicine for the diagnosis, treatment, cure, mitigation, or prevention of disease or a condition

Definition

Pharmacology concepts include:

• Composition (properties)• Uses (medical mechanism of action)• Effects (characteristics)

Related Definitions

Pharmacologist = one who has knowledge of drugs and the art of drug preparation (usually works in a research setting)

Pharmacist = health professional educated in the art of preparing and dispensing drugs (usually works in a hospital or retail pharmacy)

History of Pharmacology

Prehistoric – Accidental discoveries

Evidence of prehistoric healing arts is obtained from:

Wall Paintings

CarvingsBurial

sites

History of Pharmacology

Ancient – Known drugs and healing techniques were utilized along with magic, religion, and rituals

Use of drugs systematically recorded as evidenced by Egyptian Papyri, Cuneiform Medical Tablets, and Chinese inscriptions

History of PharmacologyClassical – First pharmacies

• Hippocrates (Father of Medicine) – Hippocratic Oath developed during this period

• Galen (incorrect anatomical descriptions unchallenged for 1500 years) – Introduced minerals to pharmacology and began to soak, boil, and mix the preparations creating syrups, tinctures, etc.

History of PharmacologyMiddle Ages – New (sweet)

formulations

• Greek and Roman teachings began to incorporate techniques from Asia

• Islamic physician Ibn Sina (aka – Avicenna) made impressive additions to the works of Galen and Dioscorides (Turkish physician – educated in Greece – wrote the first text on botany and pharmacology that was free from superstition called the De Materia Medica “on medical matters”)

History of Pharmacology

Renaissance – The age of enlightenment

• Advances in metallurgy and chemistry

History of Pharmacology

New World – Spanish exploration led to the

introduction of Central and South American remedies

to the Europeans. Some of the medicines are still in use today (e.g., ipecac, nicotine,

hallucinogenics, cocaine, and quinine – used to treat

malaria).

History of Pharmacology

Modern – Pharmacology as an individual science/legislation developed (standardization)

Principles of Surgical Pharmacology

Mathematical Calculations and Conversions

Objectives:

• Perform basic mathematical calculations to allow conversion between the various measurement systems and correct drug dosages

Measurements/Conversions

• Refer to the Metric Conversion Charts, Appendix C on Pages 1206-1207 of Surgical Technology for the Surgical Technologist: A Positive Care Approach, 4th Edition

Measurements/Conversions

• Important calculations– Concentration: ratio of solute to solvent– Dose: overall amount of medication delivered to

the patient– Application: medication’s use in the surgical

setting

Calculating Medication Dosages

• Concentration– Convert solute to solvent• A:B = C:D

• Cumulative dose– Calculated by taking the amount of solution

delivered and multiplying it by the amount of solute from the ratio above

Percentages

• Characteristics of a percentage– Represents a fraction in which the denominator is

always 100– Expressed as a whole number followed by the

percent symbol (%)– Can also be expressed as a decimal by moving the

decimal point two places to the left of the written number to indicate hundredths

Conversion of Temperature• Scales used to measure temperature – Fahrenheit and Celsius

• Monitoring body temperature is important – If not in normal range, surgical procedure may be

delayed or canceled – Hypothermia is a concern intraoperatively – Certain anesthetic agents affect the

thermoregulatory centers in the brain, leading to the body’s inability to adapt to temperature changes

Units of Measure• Metric system– Based on powers or multiples of 10 • Value of numbers established by the use and

placement of a decimal point to indicate whole numbers versus fractions

• Metric, household, and apothecary systems of measurement– Household: refer to text for abbreviations – Apothecary system: based on weight of a grain of

wheat

Weight Conversions Practice

1.5g = 1500 mg52 lb = 23.64 kg46 kg = 101.2 lb78 kg = 171.6 lb500 mg = 0.5 g4000 g = 4 kg

Weight Conversions Practice

5 g = 5000 mg240 lb = 109.09 kg300 mg = 0.3 g2 g = 2000 mg220 kg = 484 lb175 lb = 79.55 kg

Length Conversions Practice

1 m = 39.37 inches1 inch = 2.54 cm4 cm = 1.57 inches10 cm = 4 inches12 inches = 30.48 cm

Length Conversions Practice

30 cm = 12 inches6 inches = 15.24 cm1 yard = 36 inches

Volume Conversions Practice

1 ml = 1 cc4 cc = 4 ml2 oz = 60 cc5 liters = 5000 cc1.5 liters = 1500 ml

Volume Conversions Practice

0.5 oz = 15 ml500 cc = 0.5 L0.75 L = 750 cc1 gallon = 4000 cc12 ml = 0.408 oz15 gtt or minims = 0.6 cc

Temperature Conversions

(textbook method = fractions – eeeewwww!!!!)

Convert Fahrenheit to Celsius°C = (°F – 32) 5/9Which means:

1. Subtract 32 from °F2. Multiply by 53. Divide by 9

Temperature Conversions

(textbook method = fractions - eeeewwww!!!!)

Convert Celsius to Fahrenheit°F = (°C x 9/5) + 32Which means:

1. Multiply °C by 92. Divide by 53. Add 32

Temperature Conversions

(another method = no fractions – WOW!)

• Convert Fahrenheit to Celsius

(°F - 32) x 0.56 = °C

• Convert Celsius to Fahrenheit

(°C x 1.8) + 32 = °F

Temperature Conversions Practice

36° C = 96.8° F32° F = 0° C98.6° F = 37° C100° C = 212° F18° C = 64.4° F

Temperature Conversions Practice

101º F = 38.64º C104º F = 40º C212º F = 100º C37.7º C = 99.86º F91.4º F = 33º C

Basic Conversions

1. 1 g = 1000 mg 2. 1 kg = 2.2 lb3. 1 cc = 14-15 minims4. 1 L = 1000 cc5. 212º F = 100º C– Boiling Point of Water

Basic Conversions

6. 1 minim = 1 gtt7. 1 ounce = 30 cc 8. 98.6º F = 37º C9. 100 ml = 100 cc10.1 meter = 100 cm

Abbreviations Related to Medication Administration

• Medication errors have been attributed to the use of abbreviations– The Joint Commission—Official “Do Not Use” List• Refer to Table 9-11

Principles of Surgical Pharmacology

Drug Classifications, Types, and Administration

Objectives

• Discuss drug classifications and provide examples

• Identify the five main drug sources and provide examples of drugs from each source

• List and describe drug forms

Objectives

• Differentiate between the three types of drug nomenclature

• List and describe drug administration routes

Medication Information

• Basic information– Names– Classifications– Actions– Indications– Dosage

Legal Drug Classifications

• Controlled substances – Drugs with a high potential to cause psychological

and/or physical dependence and abuse

• Prescribed medications– Medications that, if used inappropriately, could

cause significant harm to the patient

Controlled Substances

• Controlled Substances (special prescription)– Schedule or Class I– Schedule or Class II– Schedule or Class III– Schedule or Class IV– Schedule or Class V

Legal Drug Classifications (cont’d.)

• Over-the-counter (OTC) medications – Prepared in a dosage that are safe to administer

without the direction of a physician

• Alternative medications– There are limited studies to determine the safety

and effectiveness of these therapies, resulting in a limited understanding

Drug Classifications

• Chemical type• Body system affected• Physiological action• Therapeutic action

Classifications

1. Analgesic Relieves pain2. Anesthetic Loss of sensation3. Antibiotic Prevent/treat infection4. Anticholinergic Block parasymp. impulses5. Anticoagulant Prevents blood clotting

Classifications

6. Antiemetic prevents N&V7. Antiinflammatory decrease swelling8. Antipyretic decrease fever9. Controlled substance narcotic 10.Contrast media X-ray delineation

Classifications

11.Cycloplegic Paralyze ciliary12.Diuretic Increase urine13.Dye Color tissue14.Fibrinolytic Dissolve clot15.Hemostatic Clot formation

Classifications

16.Hormone Endocrine secretion17.Miotic Constrict pupil18.Mydriatic Dilate pupil19.Sedative Reduce anxiety20.Vasoconstrictor Increase BP

Medications in the Operating Room

• Common pharmacologic agents used in the OR setting– Refer to Table 9-13

• Medications used by the anesthesia care provider as part of the anesthesia delivery – Refer to Table 9-20

Medications for Use with Specific Surgical Specialties

• Include:– Obstetric and gynecologic surgery: oxytocics,

vasopressin, and immunoglobin– Orthopedic surgery: antibiotics, hemostatic

agents, and steroids– Cardiovascular surgery: heparinized saline solution

Medications for Use with Specific Surgical Specialties (cont’d.)

– Neurosurgery: antibiotics, heparinized saline solution, contrast media, lidocaine HCl injection or absorbable gelatin sponge soaked in thrombin, and polifeprosan 20 with carmustine implants

– Ophthalmic surgery: Refer to Table 9-14

Drug Descriptions

1. Lidocaine Antidysrhythmic/anesthesia2. Dantrolene Treat MH3. Epinephrine Vasoconstrictor 4. Benzodiazepine Sedative 5. Atropine Anticholinergic

Drug Descriptions

6. Nitrous oxide Anesthetic (gas)7. Heparin Anticoagulant 8. Thrombin Topical hemostatic9. Mannitol Osmotic diuretic10.Bacitracin Antibiotic

Drug Identification

Adrenalin = epinephrine = vasoconstrictorAncef = cefazolin sodium = antibioticAnectine = succinylcholine chloride = depolarizing NMBBenadryl = diphenhydramine = antihistamineCoumadin = warfarin sodium = anticoagulantDantrium = dantrolene sodium = MH antagonistDecadron = dexamethasone = steroidal antiinflammatoryDemerol = meperidine HCl = narcotic analgesic

Drug Identification

Flagyl = metronidazole = anti-fungal/amebic/protozoalGelfoam = absorbable hemostatic gelatin sponge = hemostaticHeparin = heparin sodium = anticoagulantHumulin = insulin, human = hormoneKantrex = kanamycin sulfate = antibioticLasix = furosemide = loop diureticMarcaine – bupivacaine HCl = anesthetic (amino amide)

Drug Identification

Narcan = naloxone hydrochloride = narcotic antagonistPapaverine = papaverine HCl = vasopressor/vasodilatorPentothal sodium = thiopental sodium = anesthetic (induction agent)Pitocin = oxytocin = hormoneRenografin = diatrizoate meglumine, diatrizoate sodium = contrast Silvadene = silver sulfadiazine = antiinfective sulfonamideSolu-Cortef = hydrocortisone sodium succinate = steroidal antiinflammatorySublimaze = fentanyl citrate = narcotic analgesic

Drug Identification

Surgicel/Oxycel = oxidized cellulose = hemostatic agentTagamet = cimetidine = antacid/H2 BlockerToradol = ketorolac tromethamine = NSAID/nonnarcotic analgesicTracrium = atracurium besylate = nondepolarizing NMBValium = diazepam = sedative tranquilizer/benzodiazepineVersed = midazolam HCl = sedative tranquilizer/benzodiazepineWydase = hyaluronidase = enzyme/local anesthesia agonistXylocaine = lidocaine = anesthetic/cardio (amino amide)

Drug Sources

1. Plants2. Animals3. Minerals4. Laboratory synthesis5. Biotechnology

Drug Forms

1. Gas

2. Liquid

3. Solid

Drug Nomenclature

• Chemical

• Generic

• Brand

Routes of Administration

• Enteral• Topical• Inhalation• Parenteral

Principles of Surgical Pharmacology

Pharmacodynamics & Pharmacokinetics

Objectives

• Define the term pharmacokinetics and outline the process of pharmacokinesis

• Define the term pharmacodynamics and describe the three aspects of pharmacodynamics

Pharmacokinetics

Pharmacokinetics is the entire process of the drug within the body.

• Absorption• Distribution• Biotransformation• Excretion

Pharmacokinetics

Absorption

• Drug must be absorbed to produce an effect

• Absorption occurs at the site of administration (where it is absorbed into the bloodstream by the capillaries)

Pharmacokinetics

Absorption (continued)

Absorption occurs in one of two ways.

1. Passive transport

2. Active transport

PharmacokineticsAbsorption (continued)

Passive transport – Substance is moved from an area of higher concentration to an area of lower concentration until concentration on both sides of the membrane is equal.

• Passive transport requires no energy.

• Most drugs are absorbed in this manner.

Pharmacokinetics

Absorption (continued)

Active transport – Required for some drugs, glucose, and amino acids (building block of proteins).

• Requires energy in the form of ATP (a cation such as sodium) to carry the substance from the area of lower concentration to an area of higher concentration.

PharmacokineticsAbsorption (continued)

Rate of Absorption – Affects the final drug action (pharmacodynamics) and is influenced by several factors.

• Type of drug preparation• Dosage• Route of administration• Patient’s condition

Pharmacokinetics

Distribution

Transport of the drug substance to the target cells once it enters the circulatory system.

PharmacokineticsDistribution (continued)

Distribution of the drug is affected by several factors.• Rate of absorption• Cardiovascular function (systemic circulation)• Regional blood flow (perfusion) to the target organ or tissue• Drug is carried to all parts of the body; may result in effects

other than intended• Also affected by plasma protein binding, tissue binding, and

barriers (placenta/blood-brain)

PharmacokineticsBiotransformation

Biotransformation = Metabolism

• Most often occurs in the liver; however other tissues such as intestinal mucosa, lungs, kidneys, and blood plasma may be involved.

• A few drugs are converted into active substances by the liver.

Pharmacokinetics

Biotransformation (continued)

The main function of the liver in metabolism is to break down the drug molecules with enzymes for excretion. The breakdown products of metabolism are called metabolites. Metabolites are smaller, less active, or inactive substances

Pharmacokinetics

Biotransformation (continued)

The hepatic first pass effect must be considered when planning drug dosage and route of administration.

Hepatic First-Pass Effect

Hepatic Portal SystemIngested items must pass

through the hepatic portal system. The portal vein receives blood vial the tributaries from the capillaries of the abdominal viscera when then drains into the hepatic sinusoids.

Pharmacokinetics

Excretion

• The effect of the drug continues until it is biotransformed or excreted.

• Drugs are removed from the target organ (intact or biotransformed) by the circulatory system.

Pharmacokinetics

Excretion (continued)

The kidneys (with subsequent elimination in the urine) are primarily responsible for excretion.

Drug substances may also be eliminated in the feces, sweat, saliva, exhaled, or in breast milk posing a possible danger to the nursing baby.

Pharmacodynamics

• Pharmacodynamics is the interaction of the drug molecules within the target cells.

• Drug action causes an alteration in physiological activity, but is incapable of initiating new function.

• Drugs are administered to produce an expected or therapeutic effect.

Pharmacodynamics

Types of drug actions:

• Inhibition or destruction of foreign organisms• Inhibition or destruction of foreign malignant cells• Protection of cells from foreign agents• Supplementation or replacement of hormones, vitamins,

and/or enzymes• Increasing or decreasing the speed of a physiological function

Pharmacodynamics

Three aspects (time and dosage related) of pharmacodynamics:

1. Onset2. Peak effect3. Duration of action

Pharmacodynamics

Onset – Time that it takes from administration of the drug for its action to become evident.

Pharmacodynamics

Peak effect – Period of time during which the drug is at its maximum effectiveness.

Pharmacodynamics

Duration of action – Time between onset of action to the cessation of action.

Note: Timing of future dosing depends on the three aspects of pharmacodynamics. Certain variables such as type of drug, dosage, route of administration, and patient condition must also be considered when planning future doses.

Pharmacodynamics

Three theories that may explain the ways that drugs produce their effects.

1. Drug receptor interaction2. Drug enzyme interaction3. Nonspecific interaction

Pharmacodynamics

Drug receptor interaction – The active substance in the drug has an affinity for a specific chemical constituent of a cell. The interaction occurs on a molecular level on the cell surface or within the cell.

Pharmacodynamics

Drug enzyme interaction – A drug may combine with a specific enzyme to inhibit the action of the enzyme or alter the cellular response to the enzyme.

Pharmacodynamics

Nonspecific interaction – Drug accumulates on the cell membrane or penetrates the membrane and interferes physically or chemically with a cellular function or metabolic process.

Side Effects

Side effects are undesirable consequences along with the therapeutic responses to the drug.

Side effects are:• Expected• Predictable• Unavoidable• Usually tolerable or treatable

Iatrogenic Response

An iatrogenic response is a type of serious unavoidable side effect or disease induced by pharmacological therapy.

Iatrogenic Response

There are five syndromes associated with iatrogenic responses:1. Blood abnormalities2. Liver toxicity3. Kidney toxicity4. Teratogenic (causing abnormal prenatal development)5. Dermatologic

Adverse Effects

Adverse (idiosyncratic) effects are also undesirable consequences along with the therapeutic responses to the drug.

• Unintended• Usually unpredictable (certain factors such as age, weight,

time of administration may allow predictability)• Usually unavoidable• May be tolerable or treatable

Tolerance

Tolerance is a decreased therapeutic response to a drug following repeated administrations causing the dose to be increased to maintain the therapeutic effect.

Addiction

Addiction is physical or psychological dependence on a specific agent with an increasing tendency to its use or abuse.

Drug Interactions

Drug interactions may occur when two or more substances are prescribed concurrently, causing a modification of action of one or more of the substances.

• May be intentional (beneficial)• May be undesirable (detrimental)• Drug interactions are categorized as agonistic or antagonistic.

Drug Interactions

• Agonist – A drug that potentiates or enhances the effect of another.

• Antagonist – A drug that blocks the action of another.

Note – Agonists and antagonists produce no action of their own.

Principles of Surgical Pharmacology

Drug Handling

Objectives

• List and describe federal and state drug regulations• List the six “rights” for correct drug handling• List and describe methods for identification of medications• Understand medication handling techniques utilized in the

surgical environment

Drug Standards and Forms

• Drug standards– Medications in the U.S. are required to undergo

review and approval by the FDA• Refer to Table 9-3

• Drug forms– Several forms of preparation• Refer to Table 9-4

Drug-Handling Techniques

• Drug safety is of utmost concern to all involved– Know the pertinent state and federal laws– Know the policies and procedures of the health

care facility

• The Six “Rights” of Medication Administration– Refer to Table 9-12

Drug Handling Techniques

Six “RIGHTS” for correct drug handling:1. Right PATIENT2. Right DRUG3. Right DOSE4. Right ROUTE OF ADMINISTRATION5. Right FREQUENCY6. Right DOCUMENTATION

Medication Identification

• Common container types– Refer to Figures 9-1 and 9-2

• Medication labels– Refer to Figure 9-3

• See text for an example of:– The steps of administration– The interactions that occur between the circulator

and the surgical technologist during transfer

Medication Identification

Packaging

• Ampule• Vial• Preloaded syringe• Tube

Medication Identification

Ampule

Medication Identification

Vial

Medication Identification

Preloaded Syringe

Medication Identification

Tube

Medication IdentificationLabeling• Drug Name (trade and generic)• Manufacturer• Strength• Amount• Expiration Date• Route of Administration• Lot Number• Handling (storage/warnings)• Controlled Substance Classification

Medication Identification

When obtaining drugs and transferring them to the sterile field…

IDENTIFY each drug THREE TIMES

• First identification/verification• Second identification/verification• Third identification/verification

Medication Identification

How is the accomplished on the sterile field?

• Preprinted labels (stickers)• Preprinted plastic markers• Marking pen and blank label or tape

EACH LOCATION OF THE MEDICATION MUST BE LABELED!

Syringe Anatomy

A. NeedleB. Luer-Loc Tip/HubC. BarrelD. Rubber StopperE. Plunger

Note: Flange

Needle Anatomy

A. Plastic SheathB. BevelC. LumenD. PointE. LumenF. ShaftG. HiltH. Hub