Consuming grapefruit juice increases your chances of getting side effects from some medications. If you take a medication that could damage your liver, grapefruit juice might increase this risk. If you take prescription drugs or herbal remedies with side effects that include liver damage, talk to your doctor before adding grapefruit juice to your diet.
Liver Enzyme and Drug Metabolizing
The drugs that grapefruit juice can interact negatively with are drugs that are formulated to be metabolized by your liver’s CYP34A enzyme. Grapefruit juice is an inhibitor of the CYP34A liver enzyme. If you consume grapefruit juice with a medication meant to be broken down by your CYP34A enzyme, the grapefruit juice will prevent your medication from being metabolized. If your medication isn’t metabolized before filtering into your bloodstream, it will end up in your bloodstream at a stronger concentration than intended. This increases your chances of developing possible side effects that, with some medications, includes liver damage.
Statins
Statins, prescribed to treat high cholesterol, do not get properly metabolized if taken with grapefruit juice. One of the possible side effects of statins is liver damage. In fact, if you are taking statins, you should routinely get blood tests to make sure your liver is functioning properly, according to the University of Maryland Medical Center. If you take statins with grapefruit juice, your risk of liver damage is heightened, along with your risk of severe muscle damage and kidney failure. Grapefruit juice may also interfere with the metabolism of red yeast rice, a dietary supplement with properties similar to statins.
Birth Control Pills
Grapefruit juice also prevents the metabolizing of birth control pills. Side effects of birth control pills include developing tumors in your liver. Since grapefruit juice can increase the concentration of birth control pills in your bloodstream, combining grapefruit juice and birth control pills increases your risk of liver tumors. It also increases your risk of gallbladder disease, as well as your risk of developing blood clots, which can cause a stroke or a heart attack.
Other Drug Interactions
To maintain the health of your liver and the effectiveness of your CYP34A liver enzyme, as well as to avoid potentially life-threatening side effects, do not combine grapefruit juice with your medication without first consulting your doctor. You may also increase your risk for side effects if you combine grapefruit juice with calcium channel blockers, antidepressants, immunosuppressants, antihistamines, anti-anxiety medications and other psychiatric drugs. Other prescription drugs and over-the-counter remedies may also react adversely with grapefruit juice. For a complete list, consult a medical professional.
References
- The People's Pharmacy; Graedons' Guide to Grapefruit Interactions; 2002
- “The New York Times”; Experts Reveal the Secret Powers of Grapefruit Juice; Nicholas Bakalar; March 21 2006
- The Harvard Medical School Family Health Guide: Grapefruit and Medication: A Cautionary Note; Feb. 2006
- “The Sun”; Killer Grapefruit Alert To Slimmers; Emma Morton; April 3 2009
- “British Journal of Clinical Pharmacology”; Grapefruit Juice – Drug Interactions; David G. Bailey et al; March 26 1998
- University of Maryland Medical Center: Drug Treatments – Statins; Oct. 31 2006
- The American Congress of Obstetricians and Gynecologists: Birth Control Pills
- MedlinePlus: Red Yeast
