module 1 pharmacokinetics

Question 1

3 parameters of pharmacokinetics

Answer 1

clearance
volume of distribution: space in body available to contain drug
bioavailability: fraction of drug absorbed

Question 2

fundamental hypothesis of pharmacokinetics

Answer 2

pharmacologic or toxic response to a drug is related to the accessible concentration of the drug

Question 3

clearance

Answer 3

body’s ability to eliminate drug
CL= (metabolism + excretion)/drug plasma
- clearance mechanisms: metabolism, excretion

Question 4

first-order kinetics

Answer 4

inc. in plasma concentration = matched increase in clearance

Question 5

zero-order kinetics

Answer 5

increase in plasma concentration with no inc. in clearance

- saturation; enzymes are saturated

Question 6

half-life

Answer 6

time it takes for the plasma concentration to be reduced by 50%
- determines frequency of drug administration

Question 7

factors affecting half life

Answer 7

changes in Vd: age, obesity

changes in clearance

Question 8

therapeutic dosing

Answer 8

maintain Cmax below toxic levels
maintain Cmin above min. effective level
maintain Css within therapeutic window

Question 9

steady state concentration

Answer 9

peaks are constant with dosage

- takes 5 half-lives

Question 10

interpatient variability

Answer 10

due to drug-drug interactions
drug-food interactions
sex
age
renal/hepatic function 
pregnancy
genetic differences

Question 11

inter-individual response

Answer 11

reproducible

Question 12

pharmacogenetics

Answer 12

study of variability of drug response due to genetic factors

Question 13

pharmacogenomics

Answer 13

development of drugs based upon knowledge of genetic determinants that influence drug response

Question 14

single nucleotide polymorphism (SNP)

Answer 14

variation in DNA sequence consisting of a single nucleotide (ACTG) differs between individuals or paired chromosomes in an individual

Question 15

pharmacokinetics and genetic variations

Answer 15

genetic variant that alters drug metabolism, increasing or decreasing plasma concentration

Question 16

pharmacodynamics and genetic variations

Answer 16

genetic variant that reduced drug/receptor binding

Question 17

idiosyncratic reactions

Answer 17

likelihood of hypersensitivity reaction

• adverse drug reactions not known to be caused by differences in either drug metabolism or drug targets
• result from interaction between drug and some unique aspect of individual physiology

Question 18

polymorphisms affecting drug metabolism

Answer 18

ultrarapid metabolizers
extensive metabolizers (normal)
poor metabolizers

Question 19

pharmacodynamics and genetic variations

Answer 19

affect drug at therapeutic target and off-target sites

-therapeutic response differs despite appropriate drug concentrations

Question 20

poor metabolizer and drug effect

Answer 20

leads to over exposure

efficacy + dose related adverse event

Question 21

appropriate exposure/metabolizer

Answer 21

efficacy + no adverse event

Question 22

ultra- metabolizer/ under exposure

Answer 22

no efficacy + no adverse event

Question 23

genetic variability in drug target: non-responders

Answer 23

no response + no adverse event
OR
no response + target-related or off-target adverse event

Question 24

genetic variability in drug target: responders

Answer 24

response + no adverse event
OR
Response + target related or off-target adverse event