Slide 1

Pharmacology: PVN106E

Slide 2

Drugs and Factors Affecting Their Action Chapter 1

Slide 3

History of Pharmacology Plants original pharmacy Egypt: ancient remedies from over 3,000 years ago Hippocrates: natural laws to understand health and disease Various other scientists studied throughout the centuries We now have thousands of drugs available with more being developed all the time

Slide 4

Key Terms Pharmacology Pharmacodynamics Pharmacokinetics Pharmacotherapeutics Pharmacognosy Toxicology

Slide 5

Pharmacology Study of the history, sources, and physical and chemical properties of drugs Looks at the ways in which drugs affect living systems Various subdivisions of pharmacology have evolved

Slide 6

Pharmacodynamics Study of the biochemical and physiological effects of drugs Study of drugs mechanisms of action

Slide 7

Pharmacokinetics Study of the absorption, distribution, metabolism, and excretion of drugs This is drug card info

Slide 8

Pharmacotherapeutics Study of how drugs may best be used in the treatment of illnesses Which drug would be most appropriate to use for a specific disease at what dose, etc.

Slide 9

Pharmacognosy Study of drugs derived from herbal and other natural (plant and animal) drug sources Studying compositions of natural substances helps to gain knowledge for developing synthetic versions

Slide 10

Toxicology Study of poisons and poisonings All drugs have the potential to become toxic

Slide 11

Sources of Drugs Natural Semisynthetic Synthetic Biotechnology

Slide 12

Drug Uses Treatment of symptoms (pain relievers) Preventative drugs (vaccines) Diagnostic drugs (dyes) Cure (antibiotics) Health maintenance (insulin) Contraceptives (birth control)

Slide 13

Dosage Forms Tablets Time released tablets Capsules (useful for liquids) Troches or lozenges Suppositories Solutions Suspensions Emulsions Topicals Implants Parenteral products

Slide 14

Common medication routes Intravenous or IV injected into a vein Intramuscular or IM injected into a muscle Intradermal injected under the skin Subcutaneous or SQ injected into fatty tissue Oral or PO by mouth

Slide 15

U.S. Drug Legislation Pure Food and Drug Act of 1906 - Required all drugs to meet minimal standards Federal Food, Drug, and Cosmetic Act of 1938 - Required the drug to be safe before being distributed over state lines

Slide 16

U.S. Drug Legislation Comprehensive Drug Abuse Prevention and Control Act 1970 - Also known as Controlled Substance Act which classified drugs according to their abuse potential - Regulates the manufacture and distribution of drugs causing dependence

Slide 17

Controlled substances schedule Schedule IHigh abuse potential No medical useHeroin, LSD Schedule IIHigh abuse potential Accepted medical use Morphine Demerol Schedule IIILower abuse potential Accepted medical use Vicodin Tylenol/codeine Schedule IVLower abuse potential Accepted medical use Librium Valium Schedule VLowest abuse potential Accepted medical use Lomotil Robitussin AC Schedule VI (some states) Definite abuse potential Accepted medical use some states Marijuana is only drug in this category

Slide 18

Drug Classification As a result of legislation, four general drug categories were identified: 1. Prescription drugs 2. Non-prescription drugs (over the counter or OTC) 3. Investigational drugs - Drugs being tested under the FDA 4. Illicit or street drugs

Slide 19

Drug Information Resources The Physicians Desk Reference (PDR) The American Drug Index Drug Facts and Comparisons The Handbook of Non-prescription Drugs Drug Interactions The Product Insert The Pharmacist Nursing Drug Guides Formulary

Slide 20

Physicians Desk Reference (PDR) An annual publication containing several types of drug information including appearance and chemical properties of drugs. Primarily used by prescribers (physicians, nurse practitioners, etc.) The PDR can be a good reference book, but it does not provide nursing implications. Nurses may find that specific nursing drug guides are more helpful for everyday use.

Slide 21

The Product Insert A detailed description Approved by the FDA Categories - Brand name - Generic name - Description - Clinical Pharmacology - Contraindications - Warnings - Precautions - Over dosage - Dosage and administration - How supplied

Slide 22

Drug Names Chemical name - The drugs chemical composition and molecular structure Generic name (non-proprietary name) - Name given by the United States Adopted Names Council - Allows the drug to be marketed

Slide 23

Drug Names Brand name - Also called trade name (proprietary name) - The drug has a registered trademark; use of the name is restricted by the drugs owner (usually the manufacturer) for life of patent usually 17 years - Allows the drug to be commercially distributed - The superscript is registered by the U.S. Patent Office and approved by the Food and Drug Administration (FDA)

Slide 24

Examples of Drug Names Chemical name (+/-)-2-(p-isobutylphenyl) propionic acid Generic name Ibuprofen Trade or Brand name Motrin or Advil

Slide 25

Principles of Drug Action Drugs alter existing cellular or chemical functions Some drugs exert their action by forming a chemical bond with specific receptors within the body referred to as a lock and key effect - Agonists: substance that interacts with receptor to produce response - Antagonists: substance preventing action of agonist

Slide 26

Principles of Drug Action Receptors - The better the fit, the stronger the drugs affinity; therefore, the drugs effect occurs at lower doses

Slide 27

Principles of Drug Action Primary effect - Desired or therapeutic effect of the medication Secondary effect - All other effects produced by the drug, whether desirable or undesirable example: Compazines primary effect is anti-emetic. Secondary effect is anti- psychotic

Slide 28

Liberation Oral administration may require full glass of fluid to aid administration Dissolves in the gastric or intestinal fluids

Slide 29

Absorption First step in the passage of a drug into the body (bloodstream) Absorption can be faster when drug is consumed with fluids as it increases rate of dissolution Presence of food may slow absorption Most drugs are absorbed in the small intestine Bioavailability describes absorption efficiency

Slide 30

Distribution The transport of a drug in the body by the bloodstream to its site of action

Slide 31

Metabolism Occurs before excretion and makes drugs water soluble to be able to pass through the kidneys Also called biotransformation Metabolism occurs in the liver where liver enzymes react with the drug

Slide 32

Elimination/Excretion The elimination of drugs from the body - Kidneys (primary organ for excretion) - Liver - Bowel

Slide 33

Adverse Drug Reaction (ADR) ADR is the term used to describe unwanted, negative consequences associated with the use of a medication Alternative terms are side effect and adverse effect

Slide 34

Types of ADRs Allergic Reactions - Type of unpredictable ADR - Response of the Patients immune system to the presence of the drug - Does not occur unless the patient has been previously exposed to the drug - Response may range from mild (rash) to life threatening (anaphylaxis)

Slide 35

Types of ADRs Drug Idiosyncrasy - Abnormal reactivity to a drug caused by genetic differences can occur on first exposure Drug Tolerance - Patient requires a higher dosage or more frequent administration for a therapeutic effect

Slide 36

Types of ADRs Toxic Reactions - Related to dosage administered - All drugs have the capability of producing a toxic effect Teratogenic Effect - Drug causes congenital defects usually in first trimester

Slide 37

Common Lab Tests to Measure Drug Action Therapeutic levels Tests based on what the drug is supposed to do Examples: CBC for antibiotics or PTT for Coumadin, peak/trough for antibiotics (gentamicin)

Slide 38

Pharmacokinetics Half life - The time it takes for one half of the original amount of a drug to be excreted from the body Used to maintain drug levels over a 24 hour period

Slide 39

Factors Influencing Drug Response Age Weight Gender Disease Route of Administration

Slide 40

Drug Interactions Drug-drug interaction occurs when the effects of one drug are potentiated or diminished by another drug - Example: Antacids diminish the effect of tetracycline Drug-food interaction occurs when a specific food ingested increases or decreases the effect of a drug - Example: Grapefruit juice increases effects of calcium channel blockers

Slide 41

Drug Incompatibilities Drugs are chemical compounds Can interact with each other Most often an issue in parenteral administration when mixing solutions Must always determine the safety of mixing solutions before giving to patients When in doubt, give separately

Slide 42

Herbals and Botanicals Herbs are used by 80% of the world population Sold in nutrition stores, major drug chains, and discount retail stores (even supermarkets) Herbals are not regulated by the FDA Herbals are chemicals Must assess patients use of these products as some can have interactions with prescription drugs