By: Joe Hing Kwok Chu   

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The following drugs may increase the effects of warfarin:

1. acetaminophen (high dose),

2. allopurinol (Zyloprim), 

3. amiodarone (Cordarone),

4. androgens,

5. aspirin and other NSAIDs,

6. azithromycin (Zithromax),

7. bismuth subslicylate (Pepto-Bismol),

8. carbamazepine (Tegretol),

9. cephalosporins, chloral hydrate (Noctec),

10. chloramphenicol (Chloromycetin),

11. cimetidine (Tagamet), ciprofloxacin and other quinolone antibiotics,

12. cisapride (Propulsid),

13. clarithromycin (Biaxin),

14. clofibrate (Atromid-S),

15. cotrimoxazole (Bactrim),

16. dexrothyoxine, dirithromcyin and other macrolide antibiotics,

17. disopyramide (Norpace),

18. diulfiram (Antabuse),

19. erythromycin, felbamate (Felbatol),

20. fluconazole (Diflucan), fluoxetine (Prozac),

21. fluvoxamine (Luvox),

22. gemfibrozil (Lopid), gucagon,

23. HMG CoA-reductase inhibitors,

24. influenza vaccine, isoniazid (INH),

25. itraconazole (Sporanox),

26. ketoconazole (Nizoral),

27. mesna (Mesnex),

28. metronidazole (flagyl),

29. miconazole (Nonistat),

30. nonsteroidal anti-inflammatory drugs,

31. omeprazole (Prilosec),

32. pravastatin (Pravachol),

33. propranolol (Inderal),

34. quindidine (Quinaglute),

35. ranitidine (Zantac),

36. ritonavir (Norvir)  and perhaps other protease inhibitors, salicylates (aspirin),

37. sertraline (Zoloft),

38. simvastatin (Zocor),

39. simvastatin (Zocor),

40. streptokinase,

41. sulfinpyrazone (Anturane),

42. sulfonamide,

43. tamoxifen (Nolvadex),

44. tetracyclines,

45. thyroid hormones,

46. tricyclic antidepressants,

47. vancomcycin (Vancoled),

48. vitamin E

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