Common drug interactions/reactions

Question 1

Induction of P-450 enzymes

Answer 1

Drugs: Barbiturates, St.John’s wort, Phenytoin, Rifampin, Griseofulvin, Carbamazepine.

Question 2

Inhibition of P-450 enzymes

Answer 2

Drugs: Quinidine, cimetidine, ketoconazole, INH (Isoniazid), grapefruit, erythromycin, sulfonamides.

Question 3

Metabolism by P-450 enzymes

Answer 3

Drugs: -Sedatives: Barbiturates, benzodiazepines.
- Cardiac: Metoprolol, propranolol, nifedipine, warfarin, quinidine.
- Anticonvulsants: phenytoin, carbamazepine.
- Other: Theophylline, amide anesthetics.

Question 4

Increased risk of digoxin toxicity

Answer 4

Drugs: quinidine, cimetidine, amiodarone, CCBs

Question 5

Competition for albumin-binding sites

Answer 5

Drugs: Warfarin, ASA (acetylsalicylic acid, Aspirin), phenytoin.

Question 6

Blood dyscrasias

Answer 6

Drugs: Ibuprofen, quinidine, methyldopa, chemotherapeutic agents.

Question 7

Hemolysis in G6PD( glucose 6 phosphate dehydrogenase) deficient pts

Answer 7

Drugs: Sulfonamides, INH (Isoniazid), ASA, Ibuprofen, nitrofurantoin, primaquine, pyrimethamine, chloramphenicol, dapsone.

Question 8

Gynecomastia

Answer 8

Drugs: Spironolactone, Digitalis, Cimetidine, chronic alcohol use, Ketoconazole.

Question 9

Stevens-Johnson syndrome

Answer 9

Drugs: Lamotrigine, sulfonamides, penicillin.

Question 10

Photosensitivity

Answer 10

Drugs: tetracycline, amiodarone, sulfonamides.

Question 11

Drug-induced SLE

Answer 11

Drugs: Procainamide, hydralazine, INH, penicillamine, chlorpromazine, methyldopa, quinidine.