Drug interactions

Question 1

Drugs subject to chelation excretion

Answer 1

Tetracycline and Quinolone Abx

Question 2

Explain P-glycoplrotein

Answer 2

It rids body of drugs. If its blocked then toxic. If highly expressed, it takes away the effect of drugs.

Clarithromycin -blocks –toxic risk

Pheytoin–highly expresses it.. lowers efficacy of other drugs that might be excreted via P-glyc

Question 3

Common inducers of P-glyc

Answer 3

Rifampin , Phenytoin

Question 4

CYP3A4 inducers

Answer 4

Carbamazepine, Phenobarbital, phenytoin, rifampin

Question 5

PXR . . .explain

Answer 5

Drug A activates PXR nuclear receptor which then turns on CYP3A and metabolizes drug B .

Question 6

Pheytoin induces met of

Answer 6

cyclosporine

Question 7

Carbamazapine induces met of

Answer 7

Warfarin

Question 8

Rifampin induces met of

Answer 8

Estradiol

Question 9

Drug 1 is substrate of Enzyme X

If X is inhibited, by drug 2 . . .

Answer 9

Accumulation of drug 1

Question 10

Codein to morphine

Answer 10

codeine is a prodrug metabolized by CYP2D6

this enzyme can be inhibited by fluoxetine leads to inactive and diminished analgesic effect

Question 11

Timolol to inactiva metabolites

Answer 11

Timolol is active so if fluoxetine inhibits its break down can lead to toxicity

Question 12

CYP3A4 inhibitors

Answer 12

Clarithromycin
Grapefruit juice
ritonavir
ketoconazole

Mysons are grateful to navigate the Azores

Question 13

Grapfruit juice mainly inhibits

Answer 13

intestinal at low levels of consumption

Question 14

Example of beneficial drug interaction

Answer 14

Ritonavir inhibits CYP3A4