Principles of Pharmacology: Part 1

1. Principles of Pharmacology:Part 1 Lecture 8

2. Definitions Drug Biologically Active Alters cell structure/function chemically Exclude Natural Foods/Water

3. Psychoactive Drugs Alters function of nervous system Consciousness Arousal Emotions Affect Perceptions Information Processing

4. Definitions Pharmacodynamics what the drug does to the body drug action/effect Pharmacokinetics what the body does to the drug metabolism

5. Definitions Drug Action interaction of drug molecule w/ biological tissue Mechanism of action specific drug action morphine binding to opioid receptors Drug effect behavioral effects may know effect but not mechanism

6. Structure-activity relationship NT fits receptor site key & lock Change structure of drug... change its affinity increase or decrease may bind to different receptor Behavior mediated by synaptic activity

7. Drug Classification Several schemes use depends on goals Not easy to classify each drug wide range of properties Psychophramacology: Behavioral & Therapeutic

8. Classification Problems Alcohol effects General nervous system depressant Effects depend on dose Lo dose --->behavioral excitation Hi dose ---> behavioral inhibition What are the effects of alcohol? It depends!

9. Another Example Attention Deficit Hyperactive Disorder hyperkinesis Treatment: Ritalin Classify Ritalin as a sedative? Generic name: Methylphenidate a stimulant

10. No Magic Bullets! Drug delivered into system Effects all cells that have receptors Desired effect = therapeutic effect All other effects = side effects All drugs have multiple effects No magic bullets

11. What are a drug’s effects? It depends Many sources of variability A focus of this course Deciding to use a drug weigh benefits vs. risks there are always risks

12. Drug Names At least 3 names Chemical name describes molecular structure Generic name official legal name Trade name brand name Street name

13. Example: Amphetamine dl-2 amino-1 phenylpropane dl-amphetamine Benzedrine speed, bennies, whites, etc. chemical generic trade street

14. Drug Equivalence Important to know when prescribing Chemical equivalence identical chemical compounds Biological equivalence affect the same systems in same way Clinical equivalence same behavioral effect different molecules affecting different systems

15. Drug Administration & Distribution

16. How To Get From Here To There? Drug Here Target----------------->There Complex Journey

17. Routes of Administration Critical to efficacy Drug into circulatory system Crosses membranes Goes wherever blood takes it Crosses membranes Drug effects throughout body

18. Oral Per Os (PO) by mouth absorption across membrane in GI most common most variable

19. Oral Sublingual under tongue absorbed across mucous membrane salivary glands e.g., nitroglycerin

20. Chewing absorbed across lining of mouth

21. Injection Intravenous (IV) directly into vein rapid onset of fx Fastest

22. Injection Intramuscular (IM) Location important Deltoid - rapid distribution Gluteus maximus - slower Differnence in blood supply

23. Injection Intrapertoneal (IP) into peritoneal cavity of abdomen Can deliver large amounts Not used in humans much Danger of infection

24. Injection Intrathecal under sheath of nerve fibers, spinal cord, or brain Mostly as local anesthesia little importance for psychoactive drugs

25. Injection Intracranial (IC) directly into brain direct access to cells intraventricular - into CSF Effects in brain can differ from peripheral fx

26. Inhalation Smoking Lungs gases or vapors densely lined with capillaries large surface area Fast absorption Similar to IV

27. Intranasal Particles of drug insufflation = sniffed Absorption across mucous membrane of nose Not in lungs! Slower absorption FX not as strong as inhalation

28. Other routes Transdermal patches absorbed thru skin slow continuous release Researching an injection that will also Suppositories - rectal or vaginal absorption incomplete & unpredictable Pellets - Norplant Microcatheter & pump

29. The Future: Part 1 Polymer-to-gel drug + water + biodegradeable polymer 45 C: liquid & injectable 37 C: solidified gel capsule 70% of drug released over 12 days ~

30. The Future: Part 2 Injections without NEEDLES!? only some drugs enter via patch e.g. nicotine, scopolamine VLF - very low frequency sound disrupts lipid layer of skin more room for molecules to enter insulin, interferon gamma, etc works in rats & cadavers ~

31. Choice of route Consider factors Concentration in blood Rapidity of onset Duration of effects Magnitude of effects Amount delivered Patient characteristics