Be Careful When You Mix Your Drugs with Dietary Supplements

According to the Office of Dietary Supplements in the National Institutes of Health, 50 percent or more of adults in the U.S. use dietary supplements on a regular basis.

Dietary supplements include vitamins, minerals, amino acids, herbs or botanicals, and other substances that are used to supplement your diet. Some commonly used medications – both prescription drugs and over-the-counter (OTC) medications – can interact with dietary supplements, which can cause unwanted side effects or decrease the effect of your medication.

Some examples of drug interactions with dietary supplements include:

St. John's Wort: Taking this herb can interfere with enzymes in your liver, which can lower the concentration of some medications in your blood. St. John's Wort can reduce the blood level of medications such as the heart medication Lanoxin (digoxin), and the erectile dysfunction drug Viagra (sildenafil).

Vitamin E: Taking vitamin E with a blood-thinning medication such as Coumadin (warfarin) may increase your risk of bleeding.

Ginseng: This herb can enhance the bleeding effects of heparin, aspirin, and nonsteroidal anti-inflammatory drugs (NSAIDs) such as Advil (ibuprofen) and Naprosyn (naproxen).

Ginkgo Biloba: High doses of this herb can reduce the effectiveness of some medications used to control seizures – such as Tegretol (carbamazepine) and Depakote (valproic acid).

These are only a few examples of the possible interactions between medications and dietary supplements. If you take any prescription or OTC medications, talk to your pharmacist if you are using or plan to use a dietary supplement.

What do you think? Leave a comment below or in the Medication Forum.

To ask me a question about medication, email me at drugs.guide@about.com.

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