PHARM BASICS Flashcards
Time it takes for amount of drug to fall to half of its value, constant in first order kinetics (majority of drugs)
Half-life (T1/2)
Relates the amount of drug in the body to the plasma concentration
Volume of distribution (VD)
Plasma concentration of a drug at a given time
Cp
The ratio of the rate of elimination of a drug to its plasma concentration
Clearance (CL)
The elimination of drug that occurs before it reaches the systemic circulation
First pass effect
The fraction of unchanged drug that reaches systemic circulation after administration
Bioavailability (F)
When the rate of drug input equals the rate of drug elimination
Steady state
Different steps of Phase I
Oxidation, reduction, hydrolysis
Barbiturates, phenytoin, carbamazepine, and rifampin all do this
Induce CYP450
Cimetidine, ketoconazole, isoniazid, and grapefruit all do this
Inhibit CYP450
Name 3 Phase II conjugation reactions
Glucuronidation, acetylation, glutathione conjugation, glycine conjugation, sulfation, methylation, water conjugation
Constant percentage of drug metabolized per unit time
First order kinetics
Constant amount of drug metabolized per unit time
Zero order kinetics
Target plasma concentration times (volume of distribution divided by bioavailability)
Loading dose (Cp*(Vd/F))
Concentration in the plasma times (clearance divided by bioavailability)
Maintenance dose (Cp*(CL/F))
Strength of interaction between drug and its receptor
Affinity
Selectivity of a drug for its receptor
Specificity
Amount of drug necessary to elicit a biologic effect compared with another drug
Potency
Ability of drug to produce the maximal biologic effect
Efficacy
Ability of a drug to produce maximal response after binding to the receptor
Full agonist
Ability to produce less than maximal response after binding to the receptor
Partial agonist
Ability to bind reversibly to the same site as the drug and without activating the effector system
Competitive antagonist