Possible Harmful Interaction
Policosanol, derived from sugarcane, is used to reduce cholesterol levels. It also interferes with platelet clumping, creating a risk of interactions with blood-thinning drugs.
For example, a 30-day, double-blind, placebo-controlled trial of 27 individuals with high cholesterol levels found that policosanol at 10 mg daily markedly reduced the ability of blood platelets to clump together.
Another double-blind, placebo-controlled study of 37 healthy volunteers found evidence that the blood-thinning effect of policosanol increased as the dose was increased—the larger the policosanol dose, the greater the effect.
Yet another double-blind, placebo-controlled study of 43 healthy volunteers compared the effects of policosanol (20 mg daily), the blood-thinner aspirin (100 mg daily), and policosanol and aspirin combined at these same doses.
The results again showed that policosanol substantially reduced the ability of blood platelets to stick together, and that the combined therapy exhibited additive effects.
Based on these findings, you should not combine warfarin and policosanol except under medical supervision.