Interactions between herbal medicines and the anticoagulant warfarin

In each 3-treatment cross over clinical trial 2 herbal medicine will be studied. Dosage of the herbal medicines mentioned here are based upon the current information and subject to change in accordence with the latest clinical evidence which will be decided prior to each clinical trial. Variations in pharmacokinetics and pharmacodynamics of warfarin will be compared when single dose of 25 mg warfarin given alone orally (control) and when single dose of 25 mg warfarin given after 2 weeks of pre-treatment with each herbal medicine administered orally (intervention). Herbal medicines intake will be continued for one more week after warfarin administration. In total 10 herbs will be studied in 5 clinical trials. List of the proposed herbs are cranberry (6 X 500mg capsules per day of General Nutrition Corporation (GNC) cranberry juice concentrate capsules), garlic (equivalent to 4 g of fresh garlic), echinacea (4 X 1.27g tablets daily of Medi herb echinacea premium tablets), policosonal (20 mg daily), fish oil (4 g per day), CoEnzyme Q10 (50 mg per day), Soy (3.5 mg per day of phospholipids) , feverfew (100 mg of powdered feverfew daily), Milk thistle (250 mg daily of silymarin) and evening primrose oil (300 mg daily of fixed oil) .