CAM InteractionsGarlicGinkgoGinsengSaw PalmettoVitamins

Risk of drug interactions with dietary supplements

Researchers in the US reviewed the incidence and severity of potential interactions between prescription medicine and dietary supplements.

First, the details.

  • A survey was conducted on dietary supplement use among 458 patients taking prescription medications.
  • The patients listed their dietary supplements, which was compared to their prescription medication list.
  • Potential interactions were identified.

And, the results.

  • 197 patients (43%) were taking at least 1 dietary supplement with prescription medication(s).
  • The most common products:
    • Vitamins and minerals
    • Garlic
    • Ginkgo biloba
    • Saw palmetto
    • Ginseng
  • Among these, 89 (45%) had a potential for drug–dietary supplement interactions of any significance.
  • Most of these interactions (94%) were not serious.

The bottom line?

The authors concluded, “Although the use of dietary supplements appears to be very common among patients who also take prescription medications, most potential drug–dietary supplement interactions found were not serious.”

“However,” they point out, “literature support [pro and con] was sparse at best.”

Error on the side of caution. Is the perceived benefit from the supplement (or prescription drug) sufficient to warrant its use with other ongoing therapy?

9/12/11 20”01 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.