Vit E interactions

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Dear all, Here is about Vitamin E. Anupama. Vitamin E : Safety and Interactions Safety Allergies Skin reactions such as contact dermatitis and eczema have been reported with topical vitamin E preparations, such as ointments

or vitamin E containing-deodorants. Individuals with known or suspected hypersensitivity to vitamin E should avoid these products. Side Effects and Warnings Long-term (chronic) use: Recent evidence suggests that regular use of high-dose vitamin E supplements (400 IU/day or greater) may increase the risk of death (from "all causes") by a small amount. These conclusions have been criticized by some experts because they are based on re-calculations (meta-analyses) of the results of prior smaller studies which were of mixed quality, with variable results, and often in patients with chronic illnesses. Nonetheless, this is the best available scientific evidence currently, and therefore chronic use of vitamin E should be used cautiously, and high-dose vitamin E should be avoided. Acute overdose of vitamin E is very uncommon. Short-term use: For short periods of time, vitamin E

supplementation is generally considered safe at doses up to the recommended tolerable upper intake level (UL) of 1000mg per day (equivalent to 1100 IU of synthetic vitamin E or 1500 IU of natural vitamin E). However, vitamin E is possibly unsafe when used orally at doses exceeding the tolerable upper intake level. The recommended daily allowance (RDA) obtained through food consumption is considered to be safe and beneficial. Hematologic: High doses of vitamin E (greater than 400 IU/day) might increase the risk of bleeding, due to inhibition of platelet aggregation and antagonism of vitamin K-dependent clotting factors (particularly in patients with vitamin K deficiency). In studies of vitamin E, a small increase in rate of hemorrhagic (bleeding) stroke and gum bleeding has been observed, particularly which used in humans with aspirin. Increased risk of bleeding when used with warfarin (Coumadin) has been noted in animal studies. However, other studies have not

observed a greater incidence of bleeding. Bleeding has been observed in patients given high repeated doses of intravenous all-rac-alpha-tocopherol (synthetic vitamin E). Caution is advised in patients with bleeding disorders or taking drugs that may increase the risk of bleeding. Dosing adjustments may be necessary. Neurologic: In rare cases, vitamin E supplementation has been associated with dizziness, fatigue, headache, weakness, or blurred vision (particularly when used in high doses, such as 800 IU/day). Gastrointestinal: In rare cases, vitamin E supplementation has been associated with abdominal pain, diarrhea, nausea, diarrhea or flu-like symptoms (particularly when taken at high doses, such as greater than 2000 IU/day). The risk of necrotizing enterocolitis may be increased with large doses of vitamin E. Genitourinary: In rare cases, vitamin E supplementation has been associated with gonadal dysfunction and diminished kidney

function. Dermatologic: Skin reactions such as contact dermatitis and eczema have been reported with topical vitamin E preparations, such as ointments or vitamin E containing-deodorants. Ocular:Oral vitamin E should be avoided in patients with retinitis pigmentosa, as is does not appear to slow visual decline, and may be associated with more rapid loss of visual acuity, although the validity of this finding has been questioned. Pregnancy and Breastfeeding Many prenatal vitamins contain small amounts of vitamin E, for example, 18 IU. Natural forms of vitamin E may be preferable to synthetic forms. Interactions Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or

traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Interactions with Drugs Anticoagulant/antiplatelet drugs: The amount of bleeding risk associated with vitamin E remains an area of controversy, and caution is warranted in patients with a history of bleeding disorders or taking blood-thinning drugs such as aspirin, anticoagulants such as warfarin (Coumadin) or heparin, anti-platelet drugs such as clopidogrel (Plavix), and non-steroidal anti-inflammatory drugs such as ibuprofen (Motrin, Advil) or naproxen (Naprosyn, Aleve). High doses of oral or injected vitamin E may increase the risk of bleeding including hemorrhagic stroke, particularly when used in combination with aspirin. High doses increase the body's vitamin K requirement and may cause clotting abnormalities in

patients with vitamin K deficiency. In animals, vitamin E has been found to prolong prothrombin time (PT) by inhibiting vitamin K-dependent carboxylase (which may only occur in the setting of vitamin K deficiency), and is corrected by administering vitamin K. An interaction with the blood-thinner warfarin with theoretical increased bleeding risk has also been suggested in animal studies, although limited human research has suggested a lack of increased bleeding risk when combined with warfarin. Vitamin E at high doses appears to inhibit platelet aggregation and reduce platelet thromboxane production. Chemotherapy drugs: Concern has been raised that antioxidants may interfere with some chemotherapy agents (such as alkylating agents, anthracyclines, or platinums), which themselves can depend on oxidative damage to tumor cells for their anti-cancer effects. Studies of the effects of antioxidants on cancer therapies have yielded mixed results, with some reporting

interference, others noting benefits, and most suggesting no significant interaction. However, until additional scientific evidence is available, high-dose antioxidants should be avoided during chemotherapy administration, unless otherwise decided in discussion with the treating oncologist. Cholestyramine (Questran): Cholestyramine can reduce dietary vitamin E absorption and blood levels of vitamin E. Colestipol (Colestid): Colestipol can reduce dietary vitamin E absorption and blood levels of vitamin E. Cyclosporine: Vitamin E use with cyclosporine appears to increase the area under the blood concentration-time curve of cyclosporine. A water-soluble form of vitamin E, tocopheryl succinate polyethylene glycol, may improve absorption of cyclosporine (observed after liver transplantation). Gemfibrozil (Lopid): Gemfibrozil may decrease serum levels of both alpha- and gamma-tocopherol, although clinical significance is not

clear. Isoniazid (INH, Lanizid, Nydrazid): May reduce dietary vitamin E absorption. Olestra ("Olean" fat substitute): May reduce dietary vitamin E absorption. Orlistat (Xenical): May reduce dietary vitamin E absorption. Seizure medications: Anticonvulsant drugs such as Phenobarbital, phenytoin, or carbamazepine may decrease blood levels of vitamin E. Sucralfate (Carafate): May reduce dietary vitamin E absorption. Interactions with Herbs and Dietary Supplements Vitamin A: Vitamin E is involved in the absorption, storage, and utilization of Vitamin A in the body, and contributes to avoiding toxicity with Vitamin A intake. Large doses of Vitamin E may deplete Vitamin A stores. Mineral oil: May reduce dietary vitamin E absorption. Anticoagulant/antiplatelet agents: High doses of oral or injected vitamin E may increase the risk of bleeding including

hemorrhagic stroke (bleeding into the brain) and caution is warranted in patients with a history of bleeding disorders or taking herbs/supplements that may also increase the risk of bleeding. For example, multiple cases of bleeding have been reported with the use of Ginkgo biloba , and fewer cases with garlic or saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases. Some examples include: alfalfa, American ginseng, angelica, anise, Arnica montana , asafetida, aspen bark, bilberry, birch, black cohosh, bladderwrack, bogbean, boldo, borage seed oil, bromelain, capsicum, cat's claw, celery, chamomile, chaparral, clove, coleus, cordyceps, dandelion, danshen, devil's claw, dong quai, EPA (eicosapentaenoic acid, found in fish oils), evening primrose oil, fenugreek, feverfew, fish oil, flaxseed/flax powder (not a concern with flaxseed oil), ginger, grapefruit juice, grapeseed, green tea, guggul,

gymnestra, horse chestnut, horseradish, licorice root, lovage root, male fern, meadowsweet, melatonin, nordihydroguairetic acid (NDGA), omega-3 fatty acids, onion, papain, panax ginseng, parsley, passionflower, poplar, prickly Ash, propolis, quassia, red clover, reishi, Siberian ginseng, sweet clover, rue, sweet birch, sweet clover, turmeric , vitamin E, white willow, wild carrot, wild lettuce, willow, wintergreen, and yucca. In animals, vitamin E has been found to prolong prothrombin time (PT) by inhibiting vitamin K-dependent carboxylase (which may only occur in the setting of vitamin K deficiency). Vitamin E at high doses also appears to reduce platelet aggregation and thromboxane production. Omega-6 fatty acids: Increased intake of omega-6 fatty acids may increase vitamin E requirements, particularly at high doses. Vitamin K: High doses of vitamin E appear to increase the body's vitamin K requirement and may cause clotting abnormalities in

patients with vitamin K deficiency. In animals, vitamin E has been found to prolong prothrombin time (PT) by inhibiting vitamin K-dependent carboxylase, which is corrected by administering vitamin K. Zinc: Blood levels of vitamin E may be decreased with zinc deficiency. Interactions with Foods: Fish oils: Dietary fish oils can reduce vitamin E levels. The mechanism is not clear, but may result from reduced vitamin E absorption or increased vitamin E utilization by tissues. High-fat foods: Absorption of vitamin E may increase with fatty meals. Synthetic vitamin E (all-rac-alpha-tocopherol) should be taken with food for best absorption. Olestra ("Olean" fat substitute): May reduce dietary vitamin E absorption. Interactions with Lab Tests: Prothrombin time (PT)/International Normalized Ratio (INR): High-dose vitamin E (greater than 400 IU/day) appears to increase PT/INR in

patients with vitamin K deficiency, and inhibit platelet aggregation.

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