Over the past decade the popularity of coenzyme Q10, a free radical scavenger, has grown as an agent that may prevent damage to the heart when heart tissue is deprived of oxygen.² In this same period there have been a number of cases where interactions between coenzyme Q10 and warfarin (Coumadin, Jantoven) have been reported. Overall, a reduction in INR was seen in these cases. ^3,4 In a review article by Heck et al in July 2000 the authors cautioned that until further information is available, use of coenzyme Q10 and warfarin (Coumadin, Jantoven) in combination should be avoided in order to prevent blood clotting complications.⁴

  An article published in April 2003 by Engelsen et al, reports on a formal study where coenzyme Q10 was given to patients stabilized long-term on warfarin (Coumadin, Jantoven) therapy. The results of this study showed that taking coenzyme Q10 while on warfarin (Coumadin, Jantoven) did not change the warfarin (Coumadin, Jantoven) dosage needed to maintain an acceptable INR in the 2.0-4.0 range. Based on these results, it would appear safe to take coenzyme Q10 once stabilized on warfarin (Coumadin, Jantoven) therapy. ⁵ However because this was a small study, it is probably a good idea to have INR levels checked a week after either starting or stopping coenzyme Q10 to verify that the risk of bleeding or clotting is not being affected by the coenzyme Q10 doses.

  Two years after this was written, I have not seen anyone harmed by this interaction.  I agree that it is probably safe to take Co-Q-10 and warfarin (Coumadin, Jantoven) together.

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