Many people are unknowingly placing themselves in harms way by consuming grapefruit juice along with their medications. Grapefruit contains a substance that blocks the liver’s ability 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!

This can have serious complications, both acutely and over time. 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)


  1. Kane, G  et al. Drug-grapefruit juice interactions. Mayo Clin Proc 2000 Sep;75(9):933-42.
  2. 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.
  3. Wolfe S. Grapefruit juice and drug interactions. Worst Pills, Best Pills News, June 2002.