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Principles of Surgical Pharmacology ST210 Concorde 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 Carvings Burial 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 Pharmacology Classical – 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 Pharmacology Middle 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 mg 52 lb = 23.64 kg 46 kg = 101.2 lb 78 kg = 171.6 lb 500 mg = 0.5 g 4000 g = 4 kg Weight Conversions Practice 5 g = 5000 mg 240 lb = 109.09 kg 300 mg = 0.3 g 2 g = 2000 mg 220 kg = 484 lb 175 lb = 79.55 kg Length Conversions Practice 1 m = 39.37 inches 1 inch = 2.54 cm 4 cm = 1.57 inches 10 cm = 4 inches 12 inches = 30.48 cm Length Conversions Practice 30 cm = 12 inches 6 inches = 15.24 cm 1 yard = 36 inches Volume Conversions Practice 1 ml = 1 cc 4 cc = 4 ml 2 oz = 60 cc 5 liters = 5000 cc 1.5 liters = 1500 ml Volume Conversions Practice 0.5 oz = 15 ml 500 cc = 0.5 L 0.75 L = 750 cc 1 gallon = 4000 cc 12 ml = 0.408 oz 15 gtt or minims = 0.6 cc Temperature Conversions (textbook method = fractions – eeeewwww!!!!) Convert Fahrenheit to Celsius °C = (°F – 32) 5/9 Which means: 1. Subtract 32 from °F 2. Multiply by 5 3. Divide by 9 Temperature Conversions (textbook method = fractions - eeeewwww!!!!) Convert Celsius to Fahrenheit °F = (°C x 9/5) + 32 Which means: 1. Multiply °C by 9 2. Divide by 5 3. 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° F 32° F = 0° C 98.6° F = 37° C 100° C = 212° F 18° C = 64.4° F Temperature Conversions Practice 101º F = 38.64º C 104º F = 40º C 212º F = 100º C 37.7º C = 99.86º F 91.4º F = 33º C Basic Conversions 1. 2. 3. 4. 5. 1g 1 kg 1 cc 1L 212º F = = = = = 1000 mg 2.2 lb 14-15 minims 1000 cc 100º C – Boiling Point of Water Basic Conversions 6. 1 minim 7. 1 ounce 8. 98.6º F 9. 100 ml 10.1 meter = = = = = 1 gtt 30 cc 37º C 100 cc 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. 2. 3. 4. 5. Analgesic Anesthetic Antibiotic Anticholinergic Anticoagulant Relieves pain Loss of sensation Prevent/treat infection Block parasymp. impulses Prevents blood clotting Classifications 6. Antiemetic 7. Antiinflammatory 8. Antipyretic 9. Controlled substance 10.Contrast media prevents N&V decrease swelling decrease fever narcotic X-ray delineation Classifications 11.Cycloplegic 12.Diuretic 13.Dye 14.Fibrinolytic 15.Hemostatic Paralyze ciliary Increase urine Color tissue Dissolve clot Clot formation Classifications 16.Hormone 17.Miotic 18.Mydriatic 19.Sedative 20.Vasoconstrictor Endocrine secretion Constrict pupil Dilate pupil Reduce anxiety 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. 2. 3. 4. 5. Lidocaine Dantrolene Epinephrine Benzodiazepine Atropine Antidysrhythmic/anesthesia Treat MH Vasoconstrictor Sedative Anticholinergic Drug Descriptions 6. Nitrous oxide 7. Heparin 8. Thrombin 9. Mannitol 10.Bacitracin Anesthetic (gas) Anticoagulant Topical hemostatic Osmotic diuretic Antibiotic Drug Identification Adrenalin = epinephrine = vasoconstrictor Ancef = cefazolin sodium = antibiotic Anectine = succinylcholine chloride = depolarizing NMB Benadryl = diphenhydramine = antihistamine Coumadin = warfarin sodium = anticoagulant Dantrium = dantrolene sodium = MH antagonist Decadron = dexamethasone = steroidal antiinflammatory Demerol = meperidine HCl = narcotic analgesic Drug Identification Flagyl = metronidazole = anti-fungal/amebic/protozoal Gelfoam = absorbable hemostatic gelatin sponge = hemostatic Heparin = heparin sodium = anticoagulant Humulin = insulin, human = hormone Kantrex = kanamycin sulfate = antibiotic Lasix = furosemide = loop diuretic Marcaine – bupivacaine HCl = anesthetic (amino amide) Drug Identification Narcan = naloxone hydrochloride = narcotic antagonist Papaverine = papaverine HCl = vasopressor/vasodilator Pentothal sodium = thiopental sodium = anesthetic (induction agent) Pitocin = oxytocin = hormone Renografin = diatrizoate meglumine, diatrizoate sodium = contrast Silvadene = silver sulfadiazine = antiinfective sulfonamide Solu-Cortef = hydrocortisone sodium succinate = steroidal antiinflammatory Sublimaze = fentanyl citrate = narcotic analgesic Drug Identification Surgicel/Oxycel = oxidized cellulose = hemostatic agent Tagamet = cimetidine = antacid/H2 Blocker Toradol = ketorolac tromethamine = NSAID/nonnarcotic analgesic Tracrium = atracurium besylate = nondepolarizing NMB Valium = diazepam = sedative tranquilizer/benzodiazepine Versed = midazolam HCl = sedative tranquilizer/benzodiazepine Wydase = hyaluronidase = enzyme/local anesthesia agonist Xylocaine = lidocaine = anesthetic/cardio (amino amide) Drug Sources 1. 2. 3. 4. 5. Plants Animals Minerals Laboratory synthesis 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 Pharmacokinetics Absorption (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. Pharmacokinetics Absorption (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. Pharmacokinetics Distribution (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) Pharmacokinetics Biotransformation 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 System Ingested 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. Onset 2. Peak effect 3. 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 interaction 2. Drug enzyme interaction 3. 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 abnormalities 2. Liver toxicity 3. Kidney toxicity 4. 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 PATIENT 2. Right DRUG 3. Right DOSE 4. Right ROUTE OF ADMINISTRATION 5. Right FREQUENCY 6. 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 Identification Labeling • 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. B. C. D. E. Needle Luer-Loc Tip/Hub Barrel Rubber Stopper Plunger Note: Flange Needle Anatomy A. B. C. D. E. F. G. H. Plastic Sheath Bevel Lumen Point Lumen Shaft Hilt Hub