Drug Interactions

Question 1

Fluoxetine, Paroxitine, Quinidine +

Tamoxifen or Codeine

Answer 1

Decreases effectiveness of Tamoxifen or Codeine

Question 2

Digoxen +

Quinidine, Amoidarone or Verapamil

Answer 2

Increases Digoxen levels by 25-100%, risk of Bradycardia

Question 3

Grapefruit Juice +

Lovastatin, Atorvastatin, or Nifedipine

Answer 3

Increases Lovastatin, Atorvastatin, or Nifedipine absorption and effects

Question 4

Itraconazole or Gemfibrozil +

Simvastatin or Lovastatin

Answer 4

Reduced metabolism of the statins- increased myopathy

Question 5

Cholestyramine or Colestipol +

Pravastatin or Fluvastatin

Answer 5

Reduced absorption of the statins

Question 6

Propranolol +

Diltiazem or Verapamil

Answer 6

Additive Bradycardia

Question 7

Cyclosporine +

Rifampin or St. Johns Wort

Answer 7

Decreases Cyclosporine levels

Question 8

Cyclosporine +

Erythromycin, Ketoconazole, or Diltiazem

Answer 8

Increases Cyclosporine levels

Question 9

Theophylline +

Erythromycin or Ciprofloxacin

Answer 9

Increases theophylline conc. ; decreases erythromycin conc.

Question 10

Albuterol +

Propranolol

Answer 10

Decreases broncodilation (antagonists)

Question 11

Sildenafil +

Nitroglycerin or Isosorbide dinitrate

Answer 11

Additive hypotension

Question 12

Ciprofloxacin +

Mg, Fe, Ca, Zn(all 2+), Al 3+

Answer 12

decreases bioavailability of ciprofloxacin

Question 13

Caffeine +

Ciprofloxacin

Answer 13

Increased caffeine levels and effects

Question 14

Oral contraceptives +

Antibiotics ( many)

Answer 14

decreases efficacy of oral contraceptives

Question 15

Methotrexate +

Cotrimoxazole (Bactrim), NSAIDS or ASA

Answer 15

Increases Methotrexate Conc.

Question 16

Oral contraceptives +

smoking

Answer 16

Increases CV risk (MI, stroke, thromboembolism) in patients > 35 y/o

Question 17

Warfarin +

Rifampin

Answer 17

Decreases effectiveness of Warfarin

Question 18

Warfarin +

Miconazole vaginal cream

Answer 18

Increased anticoagulation

Question 19

Warfarin +

Cimetidine, cotrimoxazole, oxandrolone or amoidarone

Answer 19

Increases risk of bleeding

Question 20

Warfarin +

aspirin or NSAIDS

Answer 20

Increases risk of bleeding

Question 21

Furosemide +

NSAIDS

Answer 21

Decreases diuretic effects

Question 22

Rifampin or St. Johns Wort +

Nelfinavir, Indinavir or Ritonavir

Answer 22

Decreased protease inhibitor levels, probably decreased efficacy and increased chance of resistance

Question 23

Clonidine +

Tricyclic antidepressants

Answer 23

inhibits antihypertensive response to clonidine

Question 24

Imipramine +

Epinephrine

Answer 24

Excessive increase in blood pressure

Question 25

Allopurinol +

Azathioprine or 6-mercaptopurine

Answer 25

Increases toxicity of azathioprine (6-Mercaptopurine) (ups bioavailability)

Question 26

MAO inhibitors +

SSRIs (Fluoxetine)

Answer 26

Serotonin syndrome

Question 27

MAO inhibitors +

Pseudoephedrine

Answer 27

Severe hypertension

Question 28

Potassium +

Ace inhibitors (captopril) or spironolactone

Answer 28

increases potassium levels

Question 29

Thyroid hormone +

Ca (2+) or Raloxifene

Answer 29

reduced absorption of thyroid hormone

Question 30

Litium +

Sodium chloride

Answer 30

lithium levels change inversely proportionally to sodium levels