metabolism pharmacokinetics

Question 1

what is drug metabolism

Answer 1

biochemical modification of pharmaceutical substances by living organisms usually through specialized enzymatic activity

Question 2

do water soluble and lipid soluble substances undergo excretion?

Answer 2

no only water soluble substances do as lipid soluble substances are passively reabsorbed from renal or extra renal excretory sites into the blood

Question 3

are drugs metabolised before or after excretion

Answer 3

before

Question 4

where are main sites for metabolism

Answer 4

liver, lining of the gut

Question 5

whats the purpose of metabolism?

Answer 5

increase water solubility and so aid excretion

or to deactivate compounds

Question 6

whats a prodrug

Answer 6

compound that is metabolised into a pharmacologically active drug

Question 7

what are the effects of metabolism

Answer 7

Loss of pharmacological activity.
Decrease in activity, with metabolites that show some activity.
Increase in activity, more active metabolites.
Activation of a prodrug.
Production of toxic metabolites

Question 8

what are phase 1 reactions of metabolism

Answer 8

oxidation, reduction, hydrolysis

Question 9

which cytochrome is the most important super family of metabolising enzymes

Answer 9

P-450

Question 10

what is drug specifity determined by?

Answer 10

isoform of the cytochrome P-450

Question 11

what is the major constitutive enzyme in human liver and contributes to the metabolism of a wide range of drugs?

Answer 11

CYP3A4

Question 12

what is CYP2D6 responsible for?

Answer 12

metabolism of some antidepressants, antipsychotics and the conversion of codeine to morphine

Question 13

which enzyme is induced by smoking?

Answer 13

CYP1A2

Question 14

what does phase 2 metabolism involve?

Answer 14

conjugation

Question 15

what does conjugation increase

Answer 15

water solubillity and enhances excretion of the metabolised compound

Question 16

does conjugation usually end up in inactivation or activation

Answer 16

inactivation

Question 17

what are factors that affect metabolism

Answer 17

other drugs
genetics
hepatic blood flow
liver disease
age
sex
ethnicity 
preggers

Question 18

what are the most common enzyme inducers

Answer 18

smoking and alcohol

Question 19

why is there a wide variability in response to drugs between individuals

Answer 19

patients dont take their meds

Question 20

can lac kof activity of an enzyme result in increased drug toxicity ?

Answer 20

yes

Question 21

what are 4 phenotype subpopulations of metabolises?

Answer 21

Poor metabolizers (PM)
Intermediate metabolizers (IM)
Extensive metabolizers (EM)
Ultrarapid metabolizers (UM)

Question 22

can children metabolise quickly

Answer 22

yes

Question 23

what are the 4 pharmocokinetic areas?

Answer 23

absorption, distribution, metabolism, elimination

Question 24

why are the 4 pharmocokinetic areas important?

Answer 24

Determining how to get the drug to its site of action.
Determining dose and frequency.
Making sure the drug is present in an effective dose.
Predicting and avoiding toxicity.
Making changes based on other drugs, illness or physiological factors