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  • Grapefruit Juice Drug Interactions | Medications, Effects, & Dangers

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    Grapefruit Juice Drug Interactions | Medications, Effects, & Dangers

    Grapefruit is a citrus fruit that contains important nutrients such as vitamin C, thiamine, and potassium. 

    However, you should not drink grapefruit juice while taking certain medications. That’s because the juice contains substances that interact negatively with many prescription and over-the-counter drugs

    How Does Grapefruit Juice Affect Medications? 

    According to the U.S. Food and Drug Administration (FDA), there are two ways that grapefruit juice can interact negatively with medications.

    CYP3A4

    The first and most common way involves an enzyme called cytochrome P450 3A4, or CYP3A4. This enzyme helps metabolize (break down) drugs in your small intestine. 

    Grapefruit juice contains compounds called furanocoumarins, which block CYP3A4. When this enzyme is blocked, your body cannot properly metabolize certain drugs.

    As a result, the drugs will enter your blood in excess concentrations. This can cause a host of adverse effects. The specific effects depend on the drug, your body, and how much grapefruit juice you drank.

    Drug Transporters

    The second way involves proteins called drug transporters, which help your body absorb certain medications. Grapefruit juice can block these proteins and prevent your body from properly absorbing a drug. That means the drug may be less effective. 

    What Medications Interact With Grapefruit Juice?

    The most common classes of drugs that have potential interactions with grapefruit juice include:

    Antihistamines

    Antihistamines treat allergy symptoms. Some antihistamines, including fexofenadine (Allegra), may not work as effectively when mixed with grapefruit juice. 

    Beta Blockers

    Beta blockers treat cardiovascular problems such as high blood pressure, abnormal heart rhythms, and angina. They include acebutolol (Sectral), celiprolol (Celicard), nadolol (Corgard), and talinolol. If you drink grapefruit juice while taking these drugs, they may be less effective. 

    Calcium Channel Blockers

    Like beta blockers, calcium channel blockers treat cardiovascular problems. 

    Some of the most popular calcium channel blockers are nifedipine (Adalat, Procardia), nisoldipine (Sular), and felodipine (Plendil). When you drink grapefruit juice while taking these drugs, you may experience dangerous decreases in blood pressure and heart rate. 

    Other calcium channel blockers have little to no interactions with grapefruit juice. They include:

    • amlodipine (Norvasc)
    • diltiazem (Cardizem)
    • verapamil (Calan, Isoptin) 

    Statins

    Statins treat high cholesterol. They include atorvastatin (Lipitor), lovastatin (Mevacor), and simvastatin (Zocor). If you drink grapefruit juice while using these drugs, you may experience liver and muscle damage that could lead to kidney failure. 

    Some statins seem to be immune to the effects of grapefruit juice, including:

    • Fluvastatin (Lescol)
    • Pravastatin (Pravachol)
    • Rosuvastatin (Crestor)

    Immunosuppressants

    Immunosuppressants prevent your body from rejecting transplanted organs. They include:

    • cyclosporine (Neoral, Sandimmune)
    • sirolimus (Rapamune)
    • tacrolimus (Prograf)

    When you drink grapefruit juice while taking immunosuppressants, you may face a higher risk of infection. You might also experience other side effects, including nausea, loss of appetite, and hand trembling.

    Benzodiazepines

    Benzodiazepines help treat anxiety, insomnia, and seizures. You may experience extreme sedation and dizziness if you drink grapefruit juice while taking certain benzodiazepines, including:

    Other benzodiazepines, such as clonazepam (Klonopin) and flurazepam (Dalmane), have little to interactions with grapefruit juice.

    Other Psychiatric Medications

    Besides benzodiazepines, other psychiatric medications that can interact negatively with grapefruit juice include:

    • buspirone (BuSpar), an anti-anxiety medication
    • carbamazepine (Tegretol), an anticonvulsant that can help treat bipolar disorder
    • sertraline (Zoloft), an antidepressant

    Mixing grapefruit juice with these medications can increase your risk of side effects like nausea, vomiting, headache, dizziness, drowsiness, and diarrhea. 

    Other Drugs

    Certain drugs from other classes can also have negative interactions with grapefruit juice. 

    For example, if you drink the juice while taking the blood thinner warfarin (Coumadin, Jantoven), you may bleed more easily. 

    In addition, drinking grapefruit juice while taking the erectile dysfunction medication sildenafil (Viagra) can lead to headaches, flushing, and low blood pressure. 

    Other medications that have a higher risk of side effects when mixed with grapefruit juice include:

    • amiodarone (Cordarone, Pacerone), an antiarrhythmic that treats abnormal heart rhythms 
    • budesonide (Entocort EC and Uceris), a corticosteroid that treats Crohn’s disease and ulcerative colitis
    • saquinavir (Fortovae, Invirase), a protease inhibitor that helps prevent AIDS in people infected with HIV 

    How To Avoid Grapefruit Juice Interactions

    If you regularly drink grapefruit juice and need to start taking a drug that interacts with it, talk to your doctor. They can tell you how much grapefruit juice (if any) is safe to consume while taking the drug. 

    They can also tell you if you should avoid other fruit juices. Some of the drugs listed above also interact negatively with seville orange juice, pomelo juice, and tangelo juice. 

    Your doctor may also recommend that you stop using the drug. If you feel unable to stop using it, you may have a drug addiction. Like other diseases, addiction requires professional treatment. 

    To learn about drug addiction treatment options, please reach out to an Ark Behavioral Health specialist. Our board-certified healthcare providers offer medical detox, mental health counseling, and other evidence-based treatments to help you stay drug-free.

    Written by Ark Behavioral Health Editorial Team
    ©2024 Ark National Holdings, LLC. | All Rights Reserved.
    This page does not provide medical advice.
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