1 / 26

Pharmacology

Pharmacology. HMROBNS@aol.com Phone Number: (203) 467-0094. Pharmacokinetics & Pharmacodynamics. Injected Drugs. Pharmacokinetics. What the body does to a drug Absorption Distribution Metabolism Excretion. Pharmacodynamics. What the drug does to the body Drug effect on receptors.

lawrence-ferguson
Download Presentation

Pharmacology

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Pharmacology • HMROBNS@aol.com • Phone Number: (203) 467-0094

  2. Pharmacokinetics & Pharmacodynamics Injected Drugs

  3. Pharmacokinetics What the body does to a drug • Absorption • Distribution • Metabolism • Excretion

  4. Pharmacodynamics What the drug does to the body • Drug effect on receptors

  5. Central Compartment: Intravascular fluid and any highly perfused tissues. Highly perfused tissue receive 75% of CO, but only equal 10% of total body mass. Peripheral Compartments: Not actual area but calculated. Two Compartmental Model

  6. Plasma Concentration Curves a graphic plot of the range of plasma concentrations after an injected drug is given. Plots plasma [ ] against time. Alpha Phase distribution phase • This begins immediately after injection and reflects the drugs movement from the central compartment (circulation) to the peripheral (tissue) compartment. Beta Phase elimination phase • Follows the Alpha phase and is a more gradual decline in plasma concentrations.

  7. Plasma Concentration Slide...

  8. Terms • Elimination half time: The time necessary for the plasma concentration to fall 50% during the elimination phase (beta phase) • Context-sensitive half time: Measures half time after an infusion is stopped. • Elimination half-life: the time needed eliminate 50% of the drug from the body. • Effect-site equilibrium: delay between IV administration and desired effect. • Bioavailability- fraction of the administered drug available for absorption

  9. Distribution • Uptake • Volume of Distribution • Degree of Ionization • Protein Binding

  10. Metabolism • A. First order kinetics- Constant fraction broken down in a standard time. Independent of plasma concentrations. • B. Zero order kinetics- Constant amount is metabolized- constant amount each unit of time. example: alcohol

  11. Metabolism: Pathways • Hepatic microsomal enzymes • Non-microsomal enzymes • Oxidative • Reduction • Hydrolysis • Conjugation

  12. Clearance Hepatic clearance: • Perfusion dependent • Capacity dependent Biliary excretion: Renal clearance: • Glomerular filtration • Tubular secretion • Tubular reabsorption

  13. View Dose Response Curves....(See Slide and Handout)

  14. ED 50 Effective Dose in 50% of the population LD 50 Lethal Dose in 50% of the population Therapeutic Index LD 50/ED 50 Dose response Curves

  15. Pharmacodynamics • Receptors • Plasma Levels

  16. Terms • Sensitivity • Tolerance • Tachyphalaxis • Immunity • Agonist/Anatagonist

  17. Any Questions ???????????????????

  18. Pharmacokinetics & Pharmacodynamics Inhaled Anesthetics

  19. Pharmacokinetics • Absorption • Distribution • Metabolism • Elimination

  20. PA=Pa=Pbr • PA: Alveolar partial pressure of the gas • Pa: Arterial blood partial pressure • Pbr: Brain partial pressure

  21. MAC: Minimum Alveolar Concentration The minimum alveolar concentration that will prevent movement to a surgical stimulus in the 50% of the population

  22. Distribution:Solubility Coefficients • Blood: Gas Solubility • Oil: Gas Solubility • Tissue: Blood Solubility

  23. Increases Hyperthermia Increases in CNS catecholamines Hypernatremia Decreases Hypothermia Alpha 2 agonists Pregnancy Alcohol ingestion Lithium Decreases in CNS catecholamines Hyponatremia Factors that Affect MAC

  24. No Change in MAC... • Metabolism • Chronic alcohol abuse • Gender • Length of anesthesia • Hyperkalemia or hypokalemia

  25. Pharmacodynamics Meyer-Overton Theory Protein Receptor Theory GABA Suppression Theory

  26. Lecture Finished Go home........

More Related