Drug metabolism/ pharmacokinetics

Question 1

Drug metabolism

Answer 1

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

Question 2

Important sites of drug metabolism

Answer 2

LIVER
lining of the gut
kidneys
lungs

Question 3

Drug specificity is determined by the

Answer 3

isoform of cytochrome p450

Question 4

Cytochrome p450

Answer 4

most important super family of metabolising enzymes

Question 5

Phase 1 metabolism

Answer 5

hydrolysis, oxidation, reduction

increases the polarity of the compound and provides an active site for phase 2 metabolism

Question 6

3 most important p450 enzyme families

Answer 6

CYP1 — CYP1A2
CYP2 — CYP2D6
CYP3 — CYP3A4

Question 7

CYP3A4

Answer 7

Major constitutive enzyme in the LIVER

also found in the GUT- responsible for the pre-systemic metabolism of several drugs

DIAZEPAM/ METHEDONE

Question 8

CYP2D6

Answer 8

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

reduced or absent in 5-10% of the population

(so those people wont feel the effects of codeine)

Question 9

CYP1A2

Answer 9

induced by smoking and is important in the metabolism of theophylline

Question 10

Phase 2 drug metabolism

Answer 10

involves conjugation

conjugation increases the water solubility and enhances excretion of the metabolised compound

conjugation usually results in INACTIVATION

Question 11

Phase 2 metabolism - a molecule endogenous to the body donates a portion of itself to the foreign molecule

Answer 11

D+ENDO X –> DX+ ENDO

Question 12

the most common enzyme inducers include…

Answer 12

smoking and alcohol

process can take weeks

Question 13

Many commonly used drugs, herbal medicines and foodstuffs may inhibit…

Answer 13

drug metabolising enzymes

Question 14

CYP2D6 polymorphisms

Answer 14

70 nucleotide polymorphisms are known

Question 15

CYP2C9 (different one)

Answer 15

metabolizes 16 commonly used drugs

Warfarin and phenytoin

two allelic variants are known - does adjustments are required for drugs in individuals who have the mutant enzymes

Question 16

Drug metabolising enzymes are often deficient or reduced in

Answer 16

the fetus or premature infant

Question 17

by puberty the rate of drug metabolism is greater than

Answer 17

adults