Grapefruit juice interacts with many prescription drugs, which can cause potentially serious side effects or make some lifesaving drugs less effective.
This interaction is listed on a medication’s“drug-food interaction” label (search). But many people overlook those labels.
That’s what happened to Lucas King, a 59-year-old retired government auditor. King’s story appeared recently in the American Journal of Nursing. It’s a cautionary tale shared by Amy Karch, MS, RN, an assistant professor of clinical nursing at University of Rochester in New York.
At first, King’s health problems had nothing to do with grapefruit juice. Instead, he was facing a high risk of heart disease, like millions of Americans.
King was obese, inactive, and had a family history of heart disease. His LDL “bad” cholesterol level was way too high: 225 mg/dL, even after a month of dieting and exercising.
King’s doctor prescribed Lipitor, along with continued diet and exercise. King obeyed. His Lipitor dose was gradually increased to a high dose of 60 milligrams a day. After four months, he’d brought his LDL cholesterol down to 104. He’d also lost 36 pounds.
Later, King headed to his winter home in Florida. With a grapefruit tree on his patio, he drank two to three daily glasses of fresh grapefruit juice.
But just two months after getting the good news about his cholesterol, King was in a Florida emergency room. His symptoms: muscle pain that had started suddenly, fatigue, and high fever.
King was diagnosed with rhabdomyolysis (search), a severe muscle reaction that can cause death.
Cholesterol-lowering statin drugs (search) such as Lipitor can cause rhabdomyolysis. The possible risk is noted on the drug’s warning labels. In fact, the teaching sheet given to King may have saved his life. The sheet listed signs and symptoms of the condition, advising patients to take them seriously and seek immediate medical attention.
Lipitor was stopped and King was monitored for kidney problems, which rhabdomyolysis can trigger. He said he’d taken the prescribed doses and wasn’t taking any over-the-counter or alternative medicines.
When a nurse asked King if he’d made any changes in diet or exercise, he told her about his grapefruit juice consumption. The nurse looked up Lipitor and found that grapefruit juice slows activity of the liver enzyme that metabolizes Lipitor. This led to high drug levels in King’s body, raising the risk of rhabdomyloysis.
Most Drugs Safe
The Florida Department of Citrus (FDOC) acknowledges that grapefruit juice interacts with some cholesterol-lowering drugs.
The FDOC says grapefruit juice doesn’t interact with most prescription drugs. The FDOC also notes that patients can usually take other drugs in the same drug class that don’t interact with grapefruit juice.
That’s what King did. He was switched to another cholesterol-lowering drug, Pravachol, that doesn’t interact with grapefruit juice.
Drugs That Interact With Grapefruit Juice
Here are some drugs that interact with grapefruit juice. Check with your doctor or pharmacist if you’re concerned about any of your medications:
Xanax, Buspar, Versed, Halcion, Luvox, Zoloft, Allegra, Cordarone, quinidine, Coumadin, Tegretol, Cyclophosphamide, etoposide, ifosfamide, tamoxifen, vinblastine, vincristine, Dextromethorphan (found in many over-the-counter cold medicines), Agenerase, Crixivan, Viracept, Norvir, Fortovase, Proscar, Coreg, Cardizem, Plendil, Cardene, Adalat, Procardia, Nimotop, Sular, Covera, Calan, Verelan, Viagra, Cialis, Theophylline, high cholesterol, Lipitor, Lescol, Mevacor, Zocor, Alfenta, Duragesic, Actiq, Sufenta, Biaxin, Sporanox, erythromycin, troleandomycin.
Patients should check with their doctors about specific interactions between grapefruit juice and medication.
SOURCES: Karch, A. American Journal of Nursing, December 2004. WebMD Medical Reference from Healthwise: “Statins for High Cholesterol.” WebMD Medical Reference from Healthwise: “Selective Serotonin Reuptake Inhibitors.” News release, University of Rochester Medical Center. News release, Florida Department of Citrus.