Skip to content
My WebMD Sign In, Sign Up

Heart Disease Health Center

Font Size

Herbal Remedies May Be Risky With Heart Drugs

Researchers Say Some Supplements Should be Avoided by Patients Taking Heart Drugs
By
WebMD Health News
Reviewed by Louise Chang, MD

Feb. 1, 2010 -- Patients taking heart drugs are at risk for potentially dangerous interactions when they also take herbal supplements such as ginkgo biloba, St. John's wort, and garlic, an analysis shows.

Investigators with the Mayo Clinic identified herbal and alternative products that they say should be avoided by patients with heart disease.

They claim the products could cause problems when taken with drugs commonly prescribed to lower blood pressure, control cholesterol, stabilize heart rhythms, or prevent blood clots.

The research analysis appears in the Feb. 9 issue of the Journal of the American College of Cardiology.

Researcher Arshad Jahangir, MD, tells WebMD that heart patients often fail to tell their doctors about the alternative remedies they take because they don't recognize the potential for harm.

"Many people think that natural is synonymous with safe," he says. "Many of these herbal remedies have been used for centuries, but they may not be safe in the current era when used by patients taking many other medications."

Older Patients Most at Risk

Jahangir says the danger is especially great in elderly heart patients, who are often also taking drugs for other chronic conditions and who may already have an increased risk for bleeding.

Bleeding was one of the most frequently cited interaction risks identified by the Mayo researchers, along with reducing or increasing the potency of the prescribed medications.

Some specific examples they cited included:

  • St. John's wort, which is typically used to treat depression, anxiety, and sleep problems, has been shown in some studies to decrease the effectiveness of the arrhythmia drug digoxin, as well as blood-pressure-lowering medications and cholesterol-regulating statins. 
  • The herbal remedies alfalfa, dong quai, bilberry, fenugreek, garlic, ginger, and ginkgo biloba were all identified by the researchers as increasing bleeding risk when combined with the widely prescribed anti-clotting drug Coumadin (warfarin). Ginseng and green tea were identified as decreasing Coumadin's effects. 
  • The banned herbal product ephedra (ma-huang) has been linked to stroke, heart attack, seizures, and death from cardiac arrhythmia in otherwise healthy adults who used the product to boost energy or lose weight.

Not all interactions identified by the researchers involved herbal or alternative remedies.

Jahangir says taking heart medications with grapefruit juice is a common cause of drug toxicity.

For almost two decades, researchers have known that grapefruit juice can increase dosages of some drugs to toxic levels by inhibiting a key enzyme in the intestine that breaks down medications.

He says patients on cholesterol-lowering statins who take the drugs with grapefruit juice may end up with blood statin levels that are three to four times higher than intended.

"I think it is a good idea for anyone taking medication to avoid grapefruit juice because the effects can last as long as 24 hours," he says.

The Mayo researchers conclude that there is a clear need for increased regulation to protect the public from herbal and alternative supplements that can harm them.

Today on WebMD

x-ray of human heart
A visual guide.
atrial fibrillation
Symptoms and causes.
 
heart rate graph
10 things to never do.
Compressed heart
Article
 
empty football helmet
Article
red wine
Video
 
eating blueberries
Article
Simple Steps to Lower Cholesterol
Slideshow
 
Inside A Heart Attack
SLIDESHOW
Omega 3 Sources
SLIDESHOW
 
Salt Shockers
SLIDESHOW
lowering blood pressure
SLIDESHOW