Private MD News

Supplements may interfere with prescription drugs

Category: General Wellness

New research published in the International Journal of Clinical Practice reveals that certain herbs and dietary supplements (HDS) may cause harmful side effects in patients who are taking prescription drugs.

The study aggregated research from 54 review articles and 31 original studies, and it found that the most severe problems could be attributed to combinations of certain medications and HDS like St. John's Wort, magnesium, iron and ginkgo.

Co-author of the research, Hsiang-Wen Lin Ph.D., reported that use of HDS has been steadily increasing in the last 20 years, even though many people are unaware of the apparent risks.

"In the USA, for example, it is estimated that more than 50 per cent of patients with chronic diseases or cancer use them and that many patients take them at the same time as prescribed medication," Dr. Lin said. "Despite their widespread use, the potential risks associated with combining HDS with other medications, which include mild-to-severe heart problems, chest pain, abdominal pain and headache, are poorly understood."

According to the research, the medications that had the most negative interactions with HDS included warfarin, aspirin digoxin, ticlopidine and insulin, which is used to treat diabetes and can be diagnosed with a lab test. Many of these interactions changed how the drugs were absorbed, distributed, metabolized and eliminated by the body. Also, of the 152 contraindications, or cases in which the HDS should not be taken due to harmful consequences, 16.4 percent of them involved the gastrointestinal system, 14.5 percent involved the neurological system and 12.5 percent involved the andrenal and genitourinary diseases.

Dr. Lin also reported that herbal supplements were more likely to have negative interactions and contraindications with the medications than vitamins, minerals and amino acids.

Supplement facts
The Mayo Clinic notes that herbal supplements fall under the category of dietary supplements, so manufacturers don't need approval from the FDA to distribute them. Manufacturers can also claim that herbal supplements can help bolster health or help with a certain deficiency if they have research to back up their claims.

The FDA does regulate supplements once they're on the market, and they monitor any safety issues that may come from taking them. If a supplement is deemed unsafe, legal recourse can be taken against the manufacturer and the product may be taken off the market.

According to the Mayo Clinic, the inherent risk of taking herbal supplements comes from their active ingredients and the strong unexpected effects they can have on the body, especially if a patient is already taking a medication.