Drug Metabolism

Question 1

Give an example of a drug that is chemically activated from an inactive drug to its active substrate

Answer 1

Enalapril to enalaprilat
Codeine to morphine

Question 2

Sites for drug metabolism

Answer 2

Liver, lungs, kidney, skin , GIT

Question 3

Outcome of drug metabolism

Answer 3

Inactivation, active metabolite, active drug

Question 4

What types of enzymes are involved in drug metabolism

Answer 4

Microsomal enzymes
Non microsomal enzymes

Question 5

Another name for phase 1 reactions

Answer 5

Functionalization/ non synthetic

Question 6

List reactions that occur in phase 1

Answer 6

1) oxidative
2) reductive
3) hydro lyric rxns
Others are cyclization and decyclization

Question 7

Another name for phase 2 rxns

Answer 7

Conjugation rxns

Question 8

List the endogenous substances in phase 2 rxns

Answer 8

Glucoronide, sulphate, amino acid , acetate, glycine etc

Question 9

Location of microsomal enzymes

Answer 9

In the smooth endoplasmic reticulum of the liver, lungs, kidneys and intestinal mucosa

Question 10

Location of non microsomal enzymes

Answer 10

Cytoplasm, mitochondria, plasma

Question 11

List the microsomal enzymes

Answer 11

Monooxygenases, Cytochrome P450, UGT, epoxide hydroxylases

Question 12

List non microsomal enzymes

Answer 12

Esterases and amidases

Question 13

Microsomal enzymes are found in what phase

Answer 13

Phase 1 and 2

Question 14

Cytochrome P450 enzymes are cytoplasm bound T or F

Answer 14

F
They are membrane bound, heme containing proteins

Question 15

CYP families contain how many genes, families and sub families

Answer 15

57 genes, 18 families and 44 subfamilies

Question 16

Examples of CYP enzymes

Answer 16

CYP2D6, CYP2C19, CYP296, CYP3A4, CYP3A5

Question 17

Which CYP is involved in significantly higher number of drug metabolism compared to other enzymes

Answer 17

CYP3A4

Question 18

What does modification include

Answer 18

1) induction of drug metabolizing enzymes
2) inhibition of drug metabolizing enzymes

Question 19

Biological factors related to modification

Answer 19

Species/ strain differences (slow or fast acetylators)
Genetics
Disease state
Sex differences (M or F)
Circadian rhythm
Age
Diet
Pregnancy

Question 20

List drugs that inhibit CYP enzymes

Answer 20

CIG POKER
Cimetidine
Isoniazid
Grapefruit
Phenelzine
Omeprazole
Ketoconazole
Erythromycin
Retonavir

Question 21

List drugs that induce CYP enzymes

Answer 21

BRCC
Barbiturates
Rifampicin
Carbamazepine
Cyclophosphamide

Question 22

T or F testosterone is an enzyme inhibitor

Answer 22

F it is an enzyme inducer

Question 23

T or F felodipine is inhibited by grape fruit

Answer 23

T

Question 24

T or F progesterone is an enzyme induced

Answer 24

T

Question 25

Drugs with extensive first pass effect include

Answer 25

Lidocaine, propranolol, nitroglycerin, morphine

Question 26

Other factors that may affect first pass effect

Answer 26

Increased bioavailability in liver disease
Effects of other drugs
Individual variation in oral drug absorption