Drug Interactions with Grapefruit Juice
Medically reviewed on Feb 13, 2018 by L. Anderson, PharmD.
Which Drugs Interact with Grapefruit Juice?
While grapefruit is a nutritious and delicious fruit, many patients are concerned about the potential for drug interactions with grapefruit juice. Maybe you've receive a medication prescription container with an affixed warning label that recommends you avoid grapefruit or grapefruit juice while taking the medication.
Why is this important? Grapefruit juice affects how drugs are changed (metabolized) in the body for eventual elimination, and can alter the amount of drug in your blood. Grapefruit juice drug interactions can be researched with the Drugs.com Interaction Checker.
How Does Grapefruit Interact With Drugs?
Drugs or toxins are usually broken down (metabolized) so that they can be eliminated from the body. Grapefruit or grapefruit juice can alter enzymes in the body and affect how drugs are changed in the body before they are eliminated.
Grapefruit juice decreases the activity of the cytochrome P450 3A4 (CYP3A4) enzymes that are responsible for breaking down many drugs and toxins. Grapefruit contains compounds known as furanocoumarins that block the CYP3A4 enzymes. When grapefruit juice is consumed, the enzyme’s ability to break down the drug for elimination is decreased. Blood levels of the drug may rise, resulting in the risk for new or worsened side effects.
Examples of common medications that have a grapefruit juice interaction include felodipine (Plendil) and atorvastatin (Lipitor). If you drink grapefruit juice, always have your pharmacist run a drug interaction check with your medications to rule out an interaction before you combine them.
Will taking my medications at different times from grapefruit juice prevent the interaction?
Taking medications at a different time from when grapefruit juice is consumed will not prevent the interaction. The effects of grapefruit juice on certain medications can last for over 24 hours. So, even if the medicine is taken only once per day, grapefruit and grapefruit juice should still be avoided for the entire treatment period.1 In some cases, patients may be able to drink smaller quantities of grapefruit juice, so patients should follow the directions on the patient information leaflet for each individual drug or ask their health care provider.
What types of juice interact with drugs?
Other kinds of fruit juice, besides grapefruit juice, rarely interfere with medications. For most medications, orange juice, apple juice, or grape juice can be consumed instead of grapefruit juice. Check your prescription label or ask your pharmacist if you can consume juice with your medications.
Does Allegra interact with orange juice?
Fexofenadine (Allegra), a popular non-drowsy antihistamine available over-the-counter (OTC) can interact not only with grapefruit juice, but also with apple and orange juice. However, in the case of fexofenadine, blood levels of the drug go down and the effectiveness of the antihistamine may be reduced. This interaction occurs by a different mechanism than CYP450 3A4, but nonetheless, it is recommended that fexofenadine be taken with water, and not fruit juice.2
Talk to your healthcare provider
When new medications are started it is important to check for potential drug interactions and consult with a health care provider. Warnings labels on prescription bottles should be followed. If an interaction is found to occur, it may be possible that an alternative medication can be prescribed and the interaction can be avoided.
Drugs that can interact with grapefruit
Examples of some of the most common grapefruit or grapefruit juice drug interactions include:
- fentanyl transdermal system
Additional grapefruit juice drug interactions can be researched here.
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- FDA. FDA Consumer Health Articles. Grapefruit Juice and Medicine May Not Mix. January 2014. Accessed at http://www.fda.gov/downloads/ForConsumers/ConsumerUpdates/UCM292839.pdf
- Bailey DG, Malcolm J, Arnold O, et al. Grapefruit juice-drug interactions. Br J Clin Pharmacol 1998;46:101-110.
- Horn J, Hansten P. Fruit Juice Interactions. Pharmacy Times. Published Online Dec 1, 2005