Fibrate drugs are known to raise homocysteine levels in the blood. High levels of homocycsteine have been associated with increased risk of heart disease, although a direct connection has not been proven.

In a double-blind, placebo controlled trial of 29 men taking fenofibrate, use of the B-vitamins folate (650mcg), vitamin B12 (50mcg) and vitamin B6 (50mg) once daily for 6 weeks restored homocysteine levels to nearly normal values.1

Fibrate drugs are known to increase the "blood thinning" effects of drugs in the warfarin (Coumadin) family. Certain herbs, such as garlic, danshen, devil’s claw, dong quai, papaya, PC-SPES and red clover, may thin the blood in a manner somewhat similar to warfarin. Although no such interactions have yet been reported, it is at least theoretically possible that combined use of these herbs and fibrate drugs could pose a risk of bleeding problems.