Some herbal supplements can have dangerous interactions with heart medications.
By Mayo Clinic Staff
Herbal supplements are natural, so they must be safe, right? Not necessarily. Herbal supplements can have strong effects in the body, and some can interact with prescription medications used to treat heart and circulatory problems, such as high blood pressure and heart failure. Some of these interactions can even be dangerous.
At least a quarter of adults who take prescription medications also take dietary supplements, including herbal supplements. That number is even higher among adults older than age 70 — three-quarters report using both prescription medications and dietary supplements.
Yet many herbal supplements interact with medications for cardiovascular disease — which are widely prescribed for older adults. The chances of herbs and drugs interacting are high. Indeed, 8 of the 10 most widely used supplements interact with the blood-thinning medication warfarin (Coumadin). Here are just a few of the herbal supplements that can affect warfarin:
- Dong quai
- Evening primrose oil
- St. John's wort
That's why it's so important to talk with your doctor before taking herbal supplements if you take prescription medications. Your doctor and pharmacist can help you avoid risky interactions.
This table shows popular herbal supplements and interactions with common heart medications. It's not a complete list, however, so be sure to discuss with your doctor the medications and supplements you take.
|Herbal supplement||Medication||Potential effect
- Clopidogrel (Plavix)
- Warfarin (Coumadin)
|Increases risk of bleeding
||Increases risk of bleeding
||Decreases effectiveness of warfarin
- Beta blockers, such as atenolol (Tenormin), nadolol (Corgard) and propranolol (Inderal, Innopran XL)
|Increases blood pressure and heart rate
- Calcium channel blockers, such as diltiazem (Cardizem, Dilacor, others), nifedipine (Procardia) and verapamil (Calan, Covera-HS,Verelan)
- Nitrates, such as nitroglycerin (Nitro-Bid, Nitrostat,others) and isosorbide (Monoket, Isordil)
|Decreases blood pressure
- Digoxin (Lanoxicaps, Lanoxin)
|Increases effects of digoxin
||Decreases levels of warfarin
|St. John's wort
- Calcium channel blockers
- Dabigatran (Pradaxa)
- Rivaroxaban (Xarelto)
- Statins, such as atorvastatin (Lipitor), lovastatin (Mevacor) and simvastatin (Zocor)
|Reduces effectiveness of drugs
If your doctor tells you it's OK to use an herbal supplement combined with a medication, make sure you follow dosing instructions carefully. Watch for any unusual signs or symptoms that you could be having a drug interaction, such as rapid heartbeat, low blood sugar or changes in blood pressure.
Nov. 04, 2011
- Tachjian A, et al. Use of herbal products and potential interactions in patients with cardiovascular diseases. Journal of the American College of Cardiology. 2010;55:515.
- Gardiner P, et al. Factors associated with dietary supplement use among prescription medication users. Archives of Internal Medicine. 2006;166:1968.
- Nahin RL, et al. Concomitant use of prescription drugs and dietary supplements in ambulatory elderly people. Journal of the American Geriatric Society. 2009;57:1197.
- Natural Product/Drug Interaction Checker. Natural Medicine Comprehensive Database. http://naturaldatabase.therapeuticresearch.com/nd/Search.aspx?cs=MAYO&s=ND&pt=9&Product=warfarin. Accessed Sept. 16, 2011.
- Gardiner P, et al. Herbal and dietary supplement-drug interactions in patients with chronic illnesses. American Family Physician. 2008;77:73.
- Vogel JHK, et al. Integrating complementary medicine into cardiovascular medicine: A report of the American College of Cardiology Foundation Task Force on Clinical Expert Consensus Documents. Journal of the American College of Cardiology. 2005;46:184.
- Herbal and nonherbal supplements a danger for warfarin patients. American Heart Association. http://www.theheart.org/article/1079777.do.Accessed Sept. 29, 2011.
- Garlic. Natural Medicines Comprehensive Database. http://www.naturaldatabase.com. Accessed Sept.16, 2011.
- Ginkgo. Natural Medicines Comprehensive Database. http://www.naturaldatabase.com. Accessed Sept.16, 2011.
- Ginseng. Natural Medicines Comprehensive Database. http://www.naturaldatabase.com. Accessed Sept.16, 2011.
- Hawthorn. Natural Medicines Comprehensive Database. http://www.naturaldatabase.com. Accessed Sept.16, 2011.
- Licorice. Natural Medicines Comprehensive Database. http://www.naturaldatabase.com. Accessed Sept.16, 2011.
- St. John's wort. Natural Medicines Comprehensive Database. http://www.naturaldatabase.com. Accessed Sept.16, 2011.