Chap. 5 - pharmacological principles Flashcards
Pharmacology
Study of what drugs do and how they do it
Pharmacokinetics (includes 4 mechanisms)
Study of what the body does to drugs; includes absorption, distribution, metabolism, and excretion
Pharmacodynamics
Study of what drugs do to the body; target sites for drug actions include receptors, ion channels, enzymes, and carrier proteins.
Absorption
Method and rate at which drugs leave the site of administration
Oral meds - where are they typically absorbed and metabolized?
Absorbed in the small intestine
Metabolized in the liver
Distribution
Occurs after the drug leaves the systemic circulation and enters the interstitium and cells
Most psychotropics are lipophilic and protein bound. A patient with low protein (albumin) may become _____ from an increased amount of free drug.
Toxic
Drugs are redistributed in organs according to the _____ and _____ content of the organ.
Fat and protein
Metabolism
Process by which the drug becomes chemically altered in the body.
First-pass metabolism
Process by which the drug is metabolized by P450 enzymes in the intestines and liver before going to the systemic circulation
Elimination
Process by which the drug is removed from the body
Half-life (T1/2)
Time needed to clear 50% of the drug from the plasma
Half-life determines _____ _____
Dosing interval
Steady state
Point at which the amount of drug eliminated between doses is approximately equal to the dose administered
It takes approximately _____ half-lives to achieve a steady state and _____ half-lives to completely eliminate a drug
Five
Five
Drugs are usually administered _____ per half life to achieve steady state
Once
Tegretol, antifungals, rifampin, dilantin, phenobarbital, trileptal, and topamax are common enzyme inducers or inhibitors?
Inducers