Drugs that May Decrease the Effects of Warfarin:

By: Joe Hing Kwok Chu

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The following drugs may decrease the effects of warfarin:

1. azathioprine (Imuran),

2. barbiturates,

3. birth control pills ( oral contraceptives) ,

4. carbamazepine (Tegretol),

5. cholestyramine (Questran),

6. Coenzyme Q10 (ubiquinone or ubidecarenone), 

7. estrogens (possible),

8. ethchlorvynol (Placidyl),

9. glutethimide (Doriden),

10. griseofulvin (Gris-PEG),

11. phytonadione (vitamin K),

12. primidone (Mysoline),

13. penicillins (some) ,

14. spironolactone,

15. sucarlfate (Carafate),

16. rifampin (Rifadin),

17. thiazide diuretics.

Note: Coenzyme Q is structurally related to vitamin K (menaquinone); therefore, it possesses pro-coagulant properties.

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