Beware of Mixing Medications and Supplements

Talk with your doctor before taking herbals or dietary supplements

Dietary supplements include vitamins and minerals, as well as herbal mixes, amino acid/protein preparations and enzymes. According to the Office of Dietary Supplements in the National Institutes of Health (NIH), more than 50 percent of Americans regularly take at least one supplement on a daily basis.

A special report in The New England Journal of Medicine found that the estimated number of supplement products on the market exploded from 4,000 in 1994 to more than 55,000 in 2012.

For patients who are taking prescription heart medications for high blood pressure, high cholesterol or other cardiovascular conditions, adding dietary supplements to their regimen can be risky.

“Certain dietary supplements can reduce the amount of heart medicine that gets absorbed, meaning that you are not getting the adequate amount of your prescribed medication,” explains Eli Gelfand, MD, Section Chief of General Cardiology in the CardioVascular Institute at Beth Israel Deaconess Medical Center. “In other cases, herbs or supplements can increase the action of heart medication — and that, too, can be risky.”

In certain situations, combining medications and supplements can even be life-threatening.

“The herbal supplement gingko biloba, some garlic, green tea and grape seed supplements can interfere with blood clotting,” says Gelfand. “If you are taking a prescription blood thinner such as warfarin, clopidogrel or others, using any of these supplements can lead to internal bleeding or stroke.”

Natural Does Not Necessarily Mean Safe

Prescription medications undergo rigorous testing and are subject to careful oversight by the U.S. Food and Drug Administration (FDA) to ensure their safety and effectiveness and to determine the proper dosage for each individual. But dietary supplements are not typically subject to this same scrutiny.

Eli Gelfand, MD“

"Herbs and other supplements are not standardized dosage drugs and are not regulated as tightly as prescription medications,” explains Gelfand (right). “And while supplement labels often include the word ‘natural,’ there’s no guarantee that they are safe or advisable for everyone to use.”

According to the American College of Cardiology, herbal agents are regulated by the FDA under a category of dietary supplement, which does not need to be approved as safe or effective for a given disease or condition prior to coming on the market. The report adds that the FDA mainly monitors the safety of these supplements by reviewing reports of serious adverse events. In other words, supplements may be labeled unsafe only after they have already caused harm.

A new research review published in March 2017 in the Journal of the American College of Cardiology examined 10 herbal supplements that are often advertised as being beneficial for cardiovascular health:

  • Asian ginseng
  • astragalus
  • flaxseed oil
  • garlic gingko
  • grapeseed
  • green tea
  • hawthorn
  • milk thistle
  • soy

The reviewers concluded that there is no evidence to support the use of any of these supplements as being beneficial for heart health. Of greater concern, they reported that five of these may actually be detrimental to heart health. Green tea, garlic, ginkgo, ginseng and hawthorn actually have the potential to reduce the effectiveness of prescription heart medications or to increase side effects.

In addition, numerous supplements marketed for weight loss or energy enhancement can lead to troubling cardiovascular side effects. In the NEJM report, the authors found that weight loss and energy supplements accounted for a substantial number of emergency room visits for various cardiac symptoms, including palpitations, chest pain and tachycardia.

Always Talk with Your Doctor

medication capsules containing green leaves

The best way to prevent dangerous drug interactions is to talk with your doctor — before you begin using any dietary supplement.

“When patients are asked what other medications they are taking, they may not think to mention vitamins or herbal supplements,” says Dr. Gelfand.

He recommends that patients go through all of their medications and supplements and make a list to bring to the doctor’s office before a check-up or other appointment. Include the dosages and how often you are using supplements. Some patients find it easiest to put all their medications — prescription and non-prescription — along with any dietary supplements into a bag to bring to the appointment.

In addition, says Dr. Gelfand, “If you’re thinking of taking a supplement, contact your clinician first. And never substitute any supplement for your prescription medication. The consequences could be dangerous.”

Above content provided by the CardioVascular Institute at Beth Israel Deaconess Medical Center. For advice about your medical care, consult your doctor.

May 2017


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