Vitamins, the organic substances essential to life, influence biological activity within the body. Although you can buy vitamins over-the-counter, you should take them under the supervision of your health care provider, especially if you take any prescription medications. Some vitamins may interfere or enhance the effects of medications. Plavix, for example, is a prescription medication that affects blood clotting and taking vitamin K, a vitamin necessary for blood to clot, may affect the biological activity of Plavix.
Plavix is the brand name of the generic medication clopidogrel. Clopidogrel hydrogen sulfate, the active ingredient, affects the ability of platelets to clump together and form a blood clot. Platelets, the smallest type of blood cell, represent only fragments of cells. Platelets contain surface receptors for proteins that allow them to stick to breaks in blood vessels and to each other, making platelets vital for controlling bleeding. Adenosine diphosphate – ADP, a protein, binds to a receptor on the surface of platelets, makes them sticky and allows platelets to clump together. Plavix inhibits the binding of ADP to platelets and prevents the formation of clots.
Doctors prescribe Plavix to patients at risk for a stroke or heart attack to help prevent these life-threatening conditions. Usually, the lining of blood vessels is smooth, allowing blood to flow freely. During the process of atherosclerosis, a process in which cholesterol, fat, minerals and cellular waste build up along the walls of blood vessels, plaque forms. When plaques rupture, the platelets recognize this as an area of damage and rush to cover the plaque with a blood clot to prevent bleeding. Formation of blood clots within the blood vessels can be dangerous because when the clot breaks away it can travel to the heart and cause a heart attack or to the brain and cause a stroke.
Vitamin K also affects the ability of your blood to clot. Vitamin K activates specialized proteins known as clotting factors. These clotting factors function in a series of events, known as the coagulation cascade, that allows blood to clot to stop bleeding. A vitamin K deficiency increases your risk of excessive bleeding while too much vitamin K can cause uncontrolled clotting. Adult men should intake 120 mcg of vitamin K per day while women need only 90 mcg per day, as indicated by the Institute of Medicine. Most people meet their vitamin K intake through eating a healthy diet that includes leafy green vegetables and vegetable oils such as canola oil, soybean oil and olive oil.
Medications classified as anticoagulants, such as warfarin, act directly on vitamin K within the body to prevent the formation of blood clots. Although Plavix, classified as an antiplatelet medication, does not directly interact with vitamin K to prevent the formation of blood clots, you should avoid large fluctuations in vitamin K intake while taking any medication to treat clotting disorders. The University of Illinois College of Medicine stresses the importance of notifying your doctor of all vitamins and herbal supplements you take before starting any anti-clotting medication to reduce the chance of adverse reactions and ensure the medication can provide maximum benefits.
- Linus Pauling Institute: Vitamin K; Victoria Drake; May 2008
- “Journal of the National Medical Association”; Antiplatelet Therapy in Populations at High Risk for Atherthrombosis; Faxon et. al.; May 2006
- University of Illinois College of Medicine: Medications Used to Treat Clotting Disorders
- Institute of Medicine: Dietary Reference Intakes; 2004