The hidden risks of mixing medications and dietary supplements

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When you take prescription or over-the-counter (OTC) medications, adding a vitamin, mineral, or other dietary supplements can potentially have dangerous effects.

Robert Mozersky, a medical officer at the Food and Drug Administration (FDA), warns that some dietary supplements may increase or decrease the effect of medications, affecting their potency and possibly leading to dangerous and even life-threatening situations.

Examples of Harmful Interactions

Drugs for conditions such as HIV/AIDS, heart disease, depression, organ transplants, and birth control can become less effective when taken with St. John’s Wort, an herbal supplement.

Furthermore, combining blood thinners like warfarin with herbal supplements such as ginkgo biloba, aspirin, and vitamin E could increase the potential for internal bleeding or stroke.

Prevalence of Supplement Usage

According to the 2005-2008 National Health and Nutrition Examination Study (NHANES) by the Centers for Disease Control and Prevention (CDC), approximately 34% of participants, representing some 72 million people in the U.S., were taking dietary supplements along with prescription medication.

Misconceptions about “Natural” Products

Consumers often perceive natural products like herbal supplements or fish oil as harmless. However, Mozersky emphasizes that “natural” doesn’t always equate to safety.

These substances can interact adversely with medications or be dangerous for individuals with certain medical conditions.

Special Considerations for Children, Surgery, and Pregnancy

Children metabolize substances at different rates, which can lead to adverse effects when taking supplements along with medications.

In case of a planned surgery, some supplements can interact harmfully with necessary medications, affecting heart rate, blood pressure, or bleeding risk.

Pregnant and breastfeeding individuals should consult their healthcare professionals before taking any dietary supplements.


Before starting any dietary supplement or medication—OTC or prescription—it’s crucial to discuss it with your healthcare professional.

Always bring a list of all medications and supplements you’re currently taking, along with their dosages, to every medical appointment.

If you plan to add a new dietary supplement to your routine, inform your healthcare professional, particularly if your health status has changed recently.

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