Drug - Drug Interactions - Significant

Front 1

Warfarin (Coumadin) plus ciprofloxacin (Cipro), clarithromycin (Biaxin), erythromycin, metronidazole (Flagyl) or trimethoprimsulfamethoxazole (Bactrim, Septra)

Back 1

Increased effect of warfarin; witin 1 week:

ABX -vitK from gut flora
macrolides 1A2i = inh warfarin (R)
metronidazole 2C9i = inh warfarin (S)
bactrim 2C9i = inh warfarin (S)

Hint 1

Select alternative antibiotic.

Front 2

Warfarin plus acetaminophen

Back 2

+bleeding +INR; any time

Hint 2

Use lowest possible acetaminophen dosage and monitor INR

Front 3

Warfarin plus acetylsalicylic acid (aspirin)

Back 3

+bleeding +INR; any time

Hint 3

Limit aspirin dosage to 100 mg per day and monitor INR.

Front 4

Warfarin plus NSAID

Back 4

Increased bleeding, increased INR; any time

Hint 4

Avoid concomitant use if possible; if coadministration is necessary, use a cyclooxygenase-2 inhibitor and monitor INR.

Front 5

Fluoroquinolone plus divalent/trivalent cations or sucralfate (Carafate)

Back 5

Decreased absorption of fluoroquinolone; any time

Hint 5

Space administration by 2 to 4 hours.

Front 6

Carbamazepine (Tegretol) plus cimetidine (Tagamet), erythromycin, clarithromycin or fluconazole (Diflucan)

Back 6

Increased carbamazepine levels; 1 wk

Hint 6

Monitor carbamazepine levels.

Front 7

Phenytoin (Dilantin) plus cimetidine, erythromycin, clarithromycin or fluconazole

Back 7

Increased phenytoin levels; 1 wk

Hint 7

Monitor phenytoin levels.

Front 8

Phenobarbital plus cimetidine, erythromycin, clarithromycin or fluconazole

Back 8

Increased phenobarbital levels; 1 wk

Hint 8

Monitor phenobarbital levels; Clinical significance has not been established. Monitor

Front 9

Phenytoin plus rifampin (Rifadin)

Back 9

Decreased phenytoin levels; 1 wk

Hint 9

Clinical significance has not been established. Monitor phenytoin levels.

Front 10

Phenobarbital plus rifampin

Back 10

Decreased phenobarbital levels; 1 wk

Hint 10

Monitor phenobarbital levels.

Front 11

Carbamazepine plus rifampin

Back 11

Decreased carbamazepine levels

Hint 11

Clinical significance has not been established. Monitor carbamazepine levels.

Front 12

Lithium plus NSAID or diuretic

Back 12

Increased lithium levels

Hint 12

Decrease lithium dosage by 50% and monitor lithium levels.

Front 13

Oral contraceptive pills plus rifampin

Back 13

Decreased effectiveness of oral contraception

Hint 13

Avoid if possible; if combination is necessary recommend alternative contraception

Front 14

Oral contraceptive pills plus antibiotics

Back 14

Decreased effectiveness of oral contraception

Hint 14

Avoid if possible; if combination is necessary recommend alternative contraception

Front 15

Cisapride (Propulsid) plus erythromycin, clarithromycin, fluconazole, itraconazole (Sporanox), ketoconazole (Nizoral), nefazodone (Serzone), indinavir (Crixivan) or ritonavir (Norvir)

Back 15

Prolongation of QT interval along with arrhythmias secondary to inhibited cisapride metabolism; 1 wk

Hint 15

Avoid, consider if (Reglan) therapy is appropriate for the patient.

Front 16

Cisapride plus class IA or class III antiarrhythmic agents, tricyclic antidepressants or phenothiazine

Back 16

Prolongation of QT interval along with arrhythmias; Any time

Hint 16

Avoid. Consider whether metoclopromide therapy is appropriate for the patient.

Front 17

Sildenafil (Viagra) plus nitrates

Back 17

Dramatic hypotension; soon after taking sildenafil

Hint 17

Absolute contraindication.

Front 18

Sildenafil plus cimetidine, erythromycin, itraconazole or ketoconazole

Back 18

Increased sildenafil levels; any time

Hint 18

Initiate sildenafil at a 25-mg dose.

Front 19

HMG-CoA reductase inhibitor plus niacin, gemfibrozil (Lopid), erythromycin or itraconazole

Back 19

Possible rhabdomyolysis; any time

Hint 19

Avoid if possible. If combination therapy is necessary, monitor the patient for toxicity.

Front 20

Lovastatin (Mevacor) plus warfarin

Back 20

Increased effect of warfarin; any time

Hint 20

Monitor INR.

Front 21

SSRI plus tricyclic antidepressant

Back 21

Increased Tricyclic antidepressant level; any time

Hint 21

Monitor for anticholinergic excess and consider lower dosage of tricyclic antidepressant.

Front 22

SSRI plus selegiline (Eldepryl) or nonselective monoamine oxidase inhibitor

Back 22

Hypertensive Crisis; soon after initiation

Hint 22

Avoid.

Front 23

SSRI plus tramadol (Ultram)

Back 23

Serotonin syndrome

Hint 23

Monitor the patient for signs and symptoms of serotonin syndrome

Front 24

SSRI plus St. John's wort

Back 24

Serotonin syndrome

Hint 24

Avoid

Front 25

SSRI plus naratriptan (Amerge), rizatriptan (Mazalt), sumatriptan (Imitrex) or zolmitriptan (Zomig)

Back 25

Serotonin syndrome

Hint 25

Avoid if possible. If combination therapy is necessary, monitor the patient for signs and symptoms of serotonin syndrome

Front 26

Verapamil plus Lipitor

Back 26

Increased chance of myopathy or rhabdomylosis

Hint 26

Verapamil is a NDHP CCP and a CYP3A4 inhibitor (G-PACMAN)

Front 27

Arthrotec (misoprostol) and pregnancy

Back 27

CI - premature uteral contractions

Hint 27

Misoprostol, a prostaglandin, binds to myometrial cells to cause strong myometrial contractions leading to expulsion of tissue. This agent also causes cervical ripening with softening and dilation of the cervix.

Front 28

Amiodarone and digoxin

Back 28

Must reduce digoxin doses 30-50%

Hint 28

AmAmiodarone is a moderate inhibitor of 2C9, 2D6, and 3A4 and a substrate of 3A4 and 2C8 and a P-gp inhibitor.iodarone increases orally administered digoxin serum concentration by 70%

Front 29

Amiodarone and warfarin

Back 29

Must reduce digoxin doses 30-50%

Hint 29

Amiodarone is a moderate inhibitor of 2C9, 2D6, and 3A4 and a substrate of 3A4 and 2C8 and a P-gp inhibitor.

Front 30

amiodarone and simvastatin

Back 30

If amiodarone and simvastatin must be administered together, do not exceed 20 mg/day simvastatin

Hint 30

Simvastatin and amiodarone, a CYP3A4 inhibitor, should be coadministered with caution due to an increased risk of myopathy, including rhabdomyolysis. If amiodarone and simvastatin must be administered together, do not exceed 20 mg/day simvastatin

Front 31

amiodarone and atorvastatin

Back 31

Monitor for signs and symptoms of myopathy in patients receiving amiodarone concurrently with HMG-CoA reductase inhibitors.

Hint 31

Amiodarone may inhibit hepatic CYP3A4 isoenzymes, and therefore has the potential to increase serum concentrations of atorvastatin, cerivastatin, lovastatin, or simvastatin (CYP3A4 substrates)

Front 32

amiodarone and lovastatin

Back 32

Monitor for signs and symptoms of myopathy in patients receiving amiodarone concurrently with HMG-CoA reductase inhibitors.

Hint 32

Amiodarone may inhibit hepatic CYP3A4 isoenzymes, and therefore has the potential to increase serum concentrations of atorvastatin, cerivastatin, lovastatin, or simvastatin (CYP3A4 substrates)

Front 33

amiodarone and grapefruit

Back 33

Do not use grapefruit juice/products when using amiodarone.

Hint 33

grapefruit is a CYP3A4 inhibitor

Front 34

digoxin with cholestyramine, colestipol OR metoclopramide.

Back 34

decreased digoxin levels