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Katherine Zeratsky, R.D., L.D.
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Katherine Zeratsky, R.D., L.D.
Katherine Zeratsky, R.D., L.D.
As a specialty editor for the Food & Nutrition Center, Katherine Zeratsky helps you sort through the facts and figures, the fads and the hype to learn more about nutrition and diet.
A Marinette, Wis., native, she is certified in dietetics by the state of Minnesota and the American Dietetic Association. She has been with Mayo Clinic since 1999.
She is active in nutrition-related curriculum and course development in pediatrics at Mayo Clinic Rochester and nutrition education related to the physiology and recommended intakes for premature infants.
Other areas of interest include breast milk and formula safety, neonatal feeding, and nutrition for breast-feeding mothers.
She graduated from the University of Wisconsin-Madison, served a dietetic internship at the University of Iowa Hospitals and Clinics, and worked as a registered dietitian and health risk counselor at ThedaCare of Appleton, Wis., before joining the Mayo Clinic staff.
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Question
Grapefruit juice: Can it cause drug interactions?
I like to drink grapefruit juice. Could the juice interfere with my medications?
Answer
from Katherine Zeratsky, R.D., L.D.
Grapefruit juice provides many nutrients, including vitamin C, potassium and lycopene. But chemicals in grapefruit juice and grapefruit pulp interfere with the enzymes that break down (metabolize) various drugs in the digestive system — including certain calcium channel blockers and cholesterol-lowering drugs. The result can be excessively high levels of these drugs in the blood and an increased risk of potentially serious side effects. Pomelos and Seville oranges, a type of bitter orange often used to make marmalade and compotes, may have a similar effect.
Here's a sampling of drugs known to have potentially serious interactions with grapefruit products:
| Drug name | Type of drug |
|---|---|
| Amiodarone (Cordarone) | A drug used to treat and prevent abnormal heart rhythms (arrhythmias) |
| Buspirone (BuSpar), sertraline (Zoloft) | Antidepressants |
| Carbamazepine (Carbatrol, Tegretol) | An anti-seizure medication |
| Cyclosporine (Neoral, Sandimmune), tacrolimus (Prograf) | Immunosuppressant drugs |
| Felodipine (Plendil), nifedipine (Procardia), nimodipine (Nimotop), nisoldipine (Sular) | Calcium channel blockers used to treat high blood pressure |
| Saquinavir | An HIV medication |
| Simvastatin (Zocor), lovastatin (Mevacor), atorvastatin (Lipitor) | Statins used to treat high cholesterol |
If you're concerned about the effect grapefruit juice may have on your medications, talk to your doctor or pharmacist. In some cases, it may be important to avoid grapefruit and grapefruit products, as well as pomelos, Seville oranges and products made with these fruits. Waiting to take these medications — even up to 24 hours — after you drink grapefruit juice won't prevent an interaction. In other cases, it may be possible to switch to an alternative medication that won't interact with these fruits.
Next questionAntibiotics and alcohol: Should I avoid mixing them?
- Kiani J, et al. Medicinal importance of grapefruit juice and its interaction with various drugs. Nutrition Journal. 2007;6:33.
- Sica D. Interaction of grapefruit juice and calcium channel blockers. American Journal of Hypertension. 2006;19:768.
- Guo LQ, et al. Role of furanocoumarin derivatives on grapefruit juice-mediated inhibition of human CYP3A activity. Drug Metabolism and Disposition. 2000;28:766.
- Widmer W. One tangerine/grapefruit hybrid (tangelo) contains trace amounts of furanocoumarins at a level too low to be associated with grapefruit/drug interactions. Journal of Food Science. 2005;70:c419.
