Introduction to Pharmacology in Nursing

1. Introduction to Pharmacology in Nursing Donna Penn RN MSN CNE.

2. Nurses need to have knowledge about the actions and effects of medications • To safely and accurately administer medications nurses need to have an understanding of pharmacologic principles

3. Pharmacologic Principles

4. Chemical name • Describes the drug’s chemical composition and molecular structure Generic name (nonproprietary name) • Name given by the United States Adopted Name Council Trade name (proprietary name) • The drug has a registered trademark; use of the name restricted by the drug’s patent owner (usually the manufacturer) Drug Names

5. Chemical name • (+/-)-2-(p-isobutylphenyl) propionic acid Generic name • ibuprofen Trade name • Motrin®, Advil® Drug Names (cont'd)

6. Figure 2-1 The chemical, generic, and trade names for the common analgesic ibuprofen are listed next to the chemical structure of the drug.

7. Classification- Nurses learn to categorize meds with similar characteristics by their class • Medication classification indicates the effect of the med on the body system, the symptom the med relieves, or the med’s desired effect (e.g. oral hypoglycemics) Pharmacological Concepts: Classification

8. A medication may also be part of more than one class • Aspirin is an analgesic, antipyretic, anti-inflammatory, and anti-platelet Pharmacological Concepts: Classification

9. Medications are available in a variety of forms and preparations • The form of the med will determine its route of administration • Composition of med is designed to enhance its absorption & metabolism • Many meds are available in several forms Pharmacological Concepts: Medication Forms

10. Tablet • Capsule • Elixir • Enteric-coated • Suppository • Suspension • Transdermal patch Medication Forms

13. Pharmaceutics • Pharmacokinetics • Pharmacodynamics • Pharmacotherapeutics • Pharmacognosy Pharmacologic Principles

14. The study of how various drug forms influence pharmacokinetic and pharmacodynamic activities Pharmaceutics

15. • The study of what the body does to the drug • Absorption • Distribution • Metabolism • Excretion Pharmacokinetics

16. • The study of what the drug does to the body • The mechanism of drug actions in living tissues Pharmacodynamics

17. Figure 2-2 Phases of Drug Activity. (From McKenry LM, Salerno E: Mosby’s pharmacology in nursing—revised and updated, ed 21, St. Louis, 2003, Mosby.)

18. The use of drugs and the clinical indications for drugs to prevent and treat diseases Pharmacotherapeutics

19. The study of natural (plant and animal) drug sources Pharmacognosy

20. The rate at which a drug leaves its site of administration, and the extent to which absorption occurs • Bioavailability • Bioequivalent Pharmacokinetics: Absorption

21. Administration route of the drug • Ability of Med to Dissolve • Food or fluids administered with the drug • Body Surface Area • Status of the absorptive surface • Rate of blood flow to the small intestine • Lipid Solubility of Med • Status of GI motility Factors That Affect Absorption

22. A drug’s route of administration affects the rate and extent of absorption of that drug • Enteral (GI tract) • Parenteral • Topical Routes of Administration

23. Drug is absorbed into the systemic circulation through the oral or gastric mucosa, the small intestine, or rectum • Oral • Sublingual • Buccal • Rectal Enteral Route

24. The metabolism of a drug and its passage from the liver into the circulation • A drug given via the oral route may be extensively metabolized by the liver before reaching the systemic circulation (high first-pass effect) • The same drug—given IV—bypasses the liver, preventing the first-pass effect from taking place, and more drug reaches the circulation First-Pass Effect

26. Box 2-1 Drug Routes and First-Pass Effects

27. Intravenous (fastest delivery into the blood circulation) • Intramuscular • Subcutaneous • Intradermal • Intrathecal • Intraarticular Parenteral Route

28. Skin (including transdermal patches) • Eyes • Ears • Nose • Lungs (inhalation) • Vagina Topical Route

29. The transport of a drug in the body by the bloodstream to its site of action • Protein-binding • Water soluble vs. fat soluble • Blood-brain barrier • Areas of rapid distribution: heart, liver, kidneys, brain • Areas of slow distribution: muscle, skin, fat Distribution

31. The biologic transformation of a drug into an inactive metabolite, a more soluble compound, or a more potent metabolite • Liver (main organ) • Kidneys • Lungs • Plasma • Intestinal mucosa Metabolism(Also Known As Biotransformation)

32. Delayed drug metabolism results in: • Accumulation of drugs • Prolonged action of the drugs Stimulating drug metabolism causes: • Diminished pharmacologic effects Metabolism/Biotransformation (cont'd)

33. The elimination of drugs from the body • Kidneys (main organ) • Liver • Bowel • Biliary excretion • Enterohepatic circulation Excretion

34. 1. You are caring for a client who has diabetes complicated by kidney disease. You will need to make a detailed assessment when administering medications because this client may experience problems with: A. Absorption B. Biotransformation C. Distribution D. Excretion 35 - 34

35. Study of the mechanism of drug actions in living tissue • Drug-induced alterations to normal physiologic function • Positive change-Therapeutic effect-Goal of therapy Pharmacodynamics

36. Ways in which a drug can produce a therapeutic effect • The effects that a particular drug has depends on the cells or organ targeted by the drug • Once the drug hits its “site of action” it can modify the rate at which a cell or tissue functions Mechanism of Action

37. Receptor Interaction • Enzyme Interaction • Non-Specific Interaction Mechanism of Action

38. Drug structure is essential • Involves the selective joining of drug molecule with a reactive site on the cell surface that elicits a biological effect • Receptor is the reactive site on a cell or tissue • Once the substance binds to and interacts with the receptor, a pharmacologic response is produced Receptor Interaction

39. Affinity- degree to which a drug binds with a receptor • The drug with the best “fit” or affinity will elicit the best response • Drug can mimic body’s endogenous substances that normally bind to receptor site • Drugs that bind to receptors interact with receptors in different ways to either block or elicit a response Receptor Interaction

40. Agonist-Drug binds to receptor-there is a response (Adrenergic Agents) • Antagonist-drug binds to receptor-no response-prevents binding of agonists (Alpha & Beta Blockers) Receptor Interaction

42. Enzymes are substances that catalyze nearly every biochemical reaction in a cell • Drugs can interact with enzyme systems to alter a response • Inhibits action of enzymes-enzyme is “fooled” into binding to drug instead of target cell • Protects target cell from enzyme’s action (ACE Inhibitors) Enzyme Interaction

43. Not involving a receptor site or alteration in enzyme function • Main site of action is cell membrane or cellular process • Drugs will physically interfere or chemically alter cell process • Final product is altered causing defect or cell death • Cancer drugs, Antibiotics Non-Specific Interaction

45. The nurse is giving a medication that has a high first-pass effect. The physician has changed the route from IV to PO. The nurse expects the oral dose to be: 1. Higher because of the first-pass effect. 2. Lower because of the first-pass effect. 3. The same as the IV dose. 4. Unchanged.

46. . A patient is complaining of severe pain and has orders for morphine sulfate. The nurse knows that the route that would give the slowest pain relief would be which route? 1. IV 2. IM 3. SC 4. PO

47. Therapeutic Effect • Side Effects • Adverse Effects • Toxic Effect • Idiosyncratic Reactions • Allergic Reaction • Medication Interactions • Iatrogenic Response Type of Medication Action

48. The expected or predictable physiological response a medication causes • A single med can have several therapeutic effects (Aspirin) • It is important for the nurse to know why med is being prescribed Therapeutic Effect

49. Unintended secondary effects a medication predictably will cause • May be harmless or serious • If side effects are serious enough to negate the beneficial effect of meds therapeutic action, it may be D/C’d • People may stop taking medications because of the side effects Side Effects

50. Undesirable response of a medication • Unexpected effects of drug not related to therapeutic effect • Must be reported to FDA • Can be a side effect or a harmful effect • Can be categorized as pharmacologic, idiosyncratic, hypersensitivity, or drug interaction Adverse Effects