basic pharmacology about drugs and regulation

basic pharmacology

1. Chapter 3 Introduction to Basic Pharmacology

2. What is Pharmacology? Integrated medical science involving chemistry, biochemistry, anatomy, physiology, microbiology, and more Study of drugs, their actions, dosage, therapeutic uses, adverse effects Drug therapy is directly linked to the pathophysiology of a particular disease.

3. Difference Drugs may come from natural sources. From Plants , animals, microorganisms Isolated & refined in a lab Drugs also may be synthesized . Refined & mass produced by man 3

4. What is a drug? A substance that alters biologic activity . 4

5. Why are drugs prescribed? Promote healing Anti-inflammatory Cure disease Antibacterial Control or slow progress of a disease Cancer chemotherapy Prevent disease Vaccine

6. Drugs (Cont.) Decrease risk of complications Anticoagulants Increase function and comfort Analgesics for pain Provide replacement therapy Insulin Reduce excessive activity in the body Proton pump inhibitors

7. Disciplines of Pharmacology Pharmacodynamics : drug induced responses Pharmacokinetics : drug amounts at different sites after administration (We will discuss this in more detail later in this unit) Pharmacotherapeutics : drug choice & application Toxicology : body’s response to drugs Pharmacy :The preparation, etc of therapeutic drugs

8. Drugs are classified by Effects Classification Grouped by their primary pharmacologic action/effect Drug Classifications Therapeutic (desired) action may be: Stimulating or inhibiting cell function Such as: producing or blocking biochemical actions in tissues

9. Drug Nomenclature and Classification (know these) Each drug has a generic name, a trade name, and a chemical name Generic name : unique, official, simple name for a specific drug For example, acetaminophen Trade, proprietary, or brand name For example, Tylenol Chemical name : chemical component For example, N-(4-hydroxyphenyl) acetamide

10. Examples of Drug Nomenclature

11. FYI: Drug Regulation U.S. Food and Drug Administration * Regulates the production, labeling, distribution, and other aspects of drug control Scheduled drugs Drugs considered to have a risk for potential adverse side effects, abuse, or dependency Over-the-counter (OTC) drugs Available without prescription * Food and Drug Directorate in Canada.

12. Drug Schedules 12

13. Drug Effects (Cont.) Generally, drugs possess more than one effect on the body. Indications :Approved for uses to treat conditions for which the drug has been proved to be effective Off-label : uses for which the drug has shown effectiveness but is not the approved use. Contraindications Circumstances under which a drug should not be administered

14. Drug Effects (Cont.) Generally, drugs possess more than one effect on the body. Side effects Mild, undesirable effects of a drug, even at recommended dose Adverse or toxic effects Drug effects that are dangerous, cause significant tissue damage, or are life-threatening

15. Specific Adverse Drug Effects Hypersensitivity ― allergic reactions Reactions may be mild or can result in anaphylaxis. Idiosyncratic ( paradoxic ) reactions Unusual responses to a drug Iatrogenic Negative effect associated with administration of drug Teratogenic Harmful effect on fetus, developmental defects

16. Specific Adverse Drug Effects (Cont.) Interactions : drug effect modified by combination with another drug Synergism Effect of drug combination may be greater than the sum of the effects of the individual drugs. Antagonism Combination greatly decreases the effect of each drug. Potentiation One drug enhances the effect of a second drug.

17. Administration and Distribution of Drugs Write this onto NB paper Drugs can be administered for acting locally or have a systemic action. General Information: Drug enters body by chosen route Absorbed into blood or acts at local site Travels in the bloodstream Arrives at site of action Exerts its effect Is metabolized into inactive compounds Is excreted from the body

18. Administration and Distribution of Drugs Dose Amount of drug required to produce the desired effect in adult Expressed by a weight or measure (mcg, mg, etc.) – often show as ratio of dose/weight (mg/kg) Expressed by time factor (e.g., twice a day) Child’s dose Best calculated by child’s weight, not age – WHY? “Loading dose” Larger dose may be administered initially to raise blood levels to an effective level Not applicable to all medications – can be dangerous

19. Administration and Distribution of Drugs (Cont.) Frequency of dosing Important to maintain effective blood levels of the drug without reaching toxic levels Optimum dosing schedule Established for each drug based on Absorption, transport in the blood, half-life of the drug Timing Directions regarding Timing related to meals Daily events Sleep

20. Factors Affecting Blood Levels of Drugs Regular intake, normal distribution and excretion

21. Factors Affecting Blood Levels of Drugs (Cont.) Factors: taking drug at irregular intervals, missing doses

22. Factors Affecting Blood Levels of Drugs (Cont.) Factors: taking double dose or too frequently

23. Other Factors Influencing Blood Levels of a Drug Liver and kidney function Absorption and excretion Circulation and cardiovascular function Age Body weight and proportion of fatty tissue Activity level, exercise Food and fluid intake Genetic factors Health status, presence of other diseases, chronic or acute

24. In what situations might modifications be required in dosing & administration? Discuss in class Think about what we just wrote! 24

25. Routes, characteristics, time to onset & drug loss See Table 3.1 in your textbook Also see Ready Reference #4 for abbreviations 25

26. Routes of Drug Adminstration Enteral: (change the oral term in your notes)  involving or passing through the intestine, either naturally via the mouth and esophagus, or through an artificial opening Parenteral : Taken  into the body or administered in a manner  other  than through the digestive  tract 26

27. 27 Write this onto NB paper

28. 28

29. See Table 3-1 in textbook Enteral 29 Discuss differences in routes on Table 3-1

30. Routes of Drug Administration Discuss differences in effect times 30

31. First pass effect Refers to the metabolism of the drug in the gut (intestinal areas) or in the liver BEFORE it reaches the systemic circulation. Reduces bioavailability of the drug. First Pass Effect 31

32. Some good references on routes of administration http:// www.slideshare.net/jeevanjacob11/routes-of-drug-administration-40525364 http :// pt.slideshare.net/drchandanerd/routes-of-administration-pharmacology/16 32

33. Impact of Support 33 Patient compliance : the degree to which a  patient correctly follows medical advice

34. Prescriptions Prescription ― a signed legal document that must include the following: Write this onto NB paper Patient’s name, address, and age (if significant) Prescriber’s name, address, and identification number Date Name and amount of the drug Dosage Route and directions for using the drug Permission for additional quantities

35. Drug Mechanisms and Receptors Common pharmacologic action requires drug-receptor interaction. Drugs may stimulate receptors directly. Drugs may block receptor site for normal chemicals of the body Drugs that interact with several metabolic pathways or common functions are likely to have greater side effects .

36. Receptors and Drug Action