Galen Pharmacology - Chapter 2 with Certified Solutions

Galen Pharmacology - Chapter 2 with Certified Solutions Pharmacokinetics The process of drug movement throughout the body that is necessary to achieve drug action. Pharmacodynamics What the drug does to the body. The drugs response to the body can cause primary (desirable response) or secondary effect (desirable/undesirable) or BOTH. ex. Diphenhydramine=treats the symptoms of allergies (primary effect) but causes CNS depression that causes drowsiness in patient (secondary effect) while driving a car. Four Processes of Pharmacokinetics 1. Absorption 2. Distribution 3. Metabolism 4. Excretion ADME Absorption Movement of the drug into the bloodstream after administration. 1. Passive 2. Active 3. Pinocytosis Diffusion (Passive Transport) Drugs move across the cell membrane from an area of high concentration to lower concentration Facilitated Diffusion (Passive Transport) Depends on a carrier protein to move a drug from an area of high concentration to lower/ Active Transport Requires a carrier (enzyme or protein) to move drug against the concentration gradient. KEY WORK: ENERGY ! Pinocytosis Cells carry a drug across the membrane by engulfing the drug particles in a vesicle Bioavailability The percentage of drug available for activity. First Pass Effect When drugs are metabolized in the liver to an inactive form and are excreted, thus reducing the amount of active drug available to exert a pharmacologic effect Water Soluble (Absorption) Need a carrier (enzyme or protein) to pass membrane Lipid Soluble (Absorption) Can pass rapidly through membrane Distribution Is the movement of the drug from circulation to body tissues. Drug distribution is influenced by the rate of blood flow to the tissues, the drug's affinity to tissues and protein binding Protein Binding (Distribution) The portion of the drug that is bound to protein is inactive Free Drug (Distribution) The portion of the drug that is unbound is active Metabolism Or biotransformation is the process by which the body chemically changes drugs into a from that can be excreted. Half Life The time it takes for the amount of drug to be reduced by half Loading dose Large initial dose is given. This is significantly higher than the maintenance dosing, therapeutic effects can be obtained while steady state is reached. Excretion Elimination of drugs from the body via the kidneys. Can also be excreted through the bile, lungs, saliva, sweat and breast milk. What common test are used to determine renal function? 1. Creatinine Clearance 2. Blood Urea Nitrogen (BUN) Creatinine (Lab Values) Male: 0.6-1.2 mg/dL