Grapefruit contains a substance that blocks the liver’s capacity to metabolize certain drugs. This means that grapefruit essential stops the liver from doing its job of breaking down certain chemicals, and as a result, the blood levels of some drugs are higher and the drugs stay in the system longer. Keep in mind that while most food-drug interactions can be avoided simply by taking the substances several hours apart, grapefruit may inhibit detoxification of these substances for up to 72 hours. So if you have a glass of grapefruit juice on Monday, your body’s ability to metabolize your drug may be compromised until Thursday!
Here are some drugs that interact with grapefruit juice. Check with your doctor or pharmacist if you’re concerned about any of your medications.
| Condition | Medications |
| Anxiety / Insomnia | Xanax, Buspar, Versed, Halcion, Valium, Versed, Sonata, Desyrel |
| Depression | Luvox, Zoloft, Serzone, Anatranil |
| Bipolar disorder | Seroquel |
| Schizophrenia | Seroquel |
| Allergies | Allegra, Claritin |
| Abnormal heart rhythm | Cordarone, quinidine, Pacerone |
| Heart disease/stroke/blood clots | Coumadin |
| Epilepsy | Tegretol |
| Cancer | Cyclophosphamide, etoposide, ifosfamide, tamoxifen, vinblastine, vincristine |
| Cough | Dextromethorphan (found in many over-the-counter cold medicines) |
| HIV | Agenerase, Crixivan, Viracept, Norvir, Fortovase |
| Prostate enlargement | Proscar |
| Heart disease/High blood pressure | Coreg, Cardizem, Plendil, Cardene, Adalat, Procardia, Nimotop, Sular, Covera, Calan, Verelan, Dynacirc |
| Erectile dysfunction | Viagra, Cialis |
| Asthma/Emphysema | Theophylline |
| High cholesterol | Lipitor, Lescol, Mevacor, Zocor |
| Pain | Alfenta, Duragesic, Actiq, Sufenta |
| Infection | Biaxin, Sporanox, erythromycin, troleandomycin |
| Immunosuppressants | Neoral, Sandimmune (cyclosporine), Rapamune, Prograf |
| Contraceptives | Ethinyl estradiol (primary ingredient in oral contraceptives) |
| Steroids | Methylprednisone (Medrol) |
References
- Kane, G et al. Drug-grapefruit juice interactions. Mayo Clin Proc 2000 Sep;75(9):933-42.
- Turner E et al. Using medications safely: Interactions between grapefruit juice and prescription drugs. University of Florida Extension, Institute of Food and Agricultural Science, Feb 2002.
- Wolfe S. Grapefruit juice and drug interactions. Worst Pills, Best Pills News, June 2002.
