Is Grapefruit Affecting Your Medications?
Just one glass of grapefruit juice or half of a grapefruit can interfere with the breakdown of several commonly used oral medications. This results in greater levels of the medication in your blood than your doctor intended when writing the prescription. Specifically, "certain compounds in grapefruit juice inhibit the activity of cytochrome P450 3A4 (CYP3A4), which is one of the enzymes that metabolizes medications," explains Maria A. Summa, PharmD, BCPS, Assistant Professor of Clinical Pharmacy and Coordinator of Drug Information Services at the Massachusetts College of Pharmacy and Health Sciences. About 60% of drugs are broken down by CYP3A4.
Higher levels of drugs circulating in the bloodstream can enhance therapeutic effects or increase the risk of toxicity. Some of the many medications affected by grapefruit are listed in the table below. Please be aware that this is not a complete table. Talk to your doctor about the medications you are taking to see if they are affected by grapefruit. Those taken on a regular basis are more likely to be affected than something taken as a one-time dose.
Don't take this information to mean you should avoid grapefruit and its juice; both bring you a healthy dose of vitamins and phytochemicals. Rather, check with your doctor or pharmacist before changing your habits to determine how grapefruit can fit in with your medication regimen.
Type of medication | Brand names of medications |
---|---|
AIDS medications |
Crixivan
Fortovase Invirase Norvir Viracept |
Anti-anxiety medications; sleep aids |
Ambien
BuSpar Halcion Sonata Valium Versed Xanax |
Antibiotics | Erythromycin |
Antihistamines | Allegra |
Asthma medication |
Serevent
Singulair |
Cancer treatments |
Oncovin
Paxene Taxol Vincasar Iressa |
Cholesterol-lowering drugs |
Lipitor
Mevacor Zocor Nolvadex And all other drugs in the statin family |
Heart medications |
Adalat
Cardene Cardioquin Cardizem Coreg Plendil Procardia Nimotop Sular |
Hormones |
Anabolic steroids (testosterone)
Tikosyn Birth control pills |
Pain relievers |
Actiq
Alfenta Codeine Colchicine Dolophine (methadone) Duragesic (fentanyl) |
Post-transplant medications |
Neoral
Prograf Sandimmune |
Steroids |
Glucocorticoids
(Hydrocortisone) |
Miscellaneous drugs |
Dapsone
Dextromethorphan Tegretol Flomax Sporanox |
RESOURCES:
Drug Interactions
http://medicine.iupui.edu
U.S. Food and Drug Administration
http://www.fda.gov
U.S. Pharmacopeia
http://www.usp.org
CANADIAN RESOURCES:
Dietitians of Canada
http://www.dietitians.ca/
Health Canada
http://www.hc-sc.gc.ca/index_e.html
Last reviewed November 2009 by Brian Randall, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
Copyright © 2007 EBSCO Publishing All rights reserved.