definitions B1

Question 1

define bioavailability

Answer 1

the rate n extent by which a drug reaches systemic circulation in a unchanged form

Question 2

biotransformation

Answer 2

enzyme catalyzed biochemical transformation of drugs within the living organism

Question 2

drug clearance

Answer 2

theoretical volume of plasma from which the drug is completely removed in unit time

Question 3

plasma half life

Answer 3

time required for the plasma concentration of drug to reduce 50% of its original value

Question 4

first order kinetics

Answer 4

constant fraction of the drug present in the body eliminated in unit time

Question 5

zero order kinetics

Answer 5

constant amount of drug is eliminated in unit time

Question 6

receptor

Answer 6

any cellular macromolecule located on /within cell to which a drug can bind n initiate its effect

Question 7

ligand

Answer 7

any molecule that can interact with a receptor

Question 8

affinity

Answer 8

ability of drug to bind to the receptor

Question 9

intrinsic activity

Answer 9

ability of drug to activate n induce a conformational change in the receptor aft occupying the receptor

Question 10

agonist

Answer 10

chemicals that interact with a receptor n initiate a chemical reaction inside cell n produce effect
exp:Ach is agonist at muscarinic receptor in the heart cell
have affinity n intrinsic activity

Question 11

antagonist

Answer 11

drug that binds to receptor but x activate it.blocks effect of an agonist for that receptor

exp;d-tubocurarine antagonist of Ach
have affinity only

Question 12

potency

Answer 12

dose of a drug that is req to prod a defined effect

Question 13

efficacy

Answer 13

dose of a drug that is producing max effect of the drug

Question 14

ED50

Answer 14

the dose of a medication that produces a desired pharmacologic effect in 50% of subjects

Question 15

chemotherapy

Answer 15

the treatment with drugs that have selective toxicity for an invading pathogen without causing harm to the host

Question 16

empirical therapy

Answer 16

use of AMA b4 identification of causative organism n susceptibility test

Question 17

definitive therapy

Answer 17

use of AMA aft identification of causative organism adt availability of AST results

Question 18

steady state concentration

Answer 18

if constant doese of drug is given at constant interveals at its t1/2,plasma con.c of drug increase to its absorption n falls due to elimination in each dosing interval

the amount of drug eliminated= amount of drug administered in the dosing interval

Question 19

apparent volume of distribution

Answer 19

hypothetical vol of body fluid into which a drug is uniformly distributed at a concentration equal to that of plasma ,assuming body to be a single compartment

Question 20

therapeutic index

Answer 20

a measure of drug safety
-higher index,safer drug