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What is the most important information I should know about grapefruit interactions?Grapefruit and grapefruit juice can affect how some bipolar medications are metabolized. Always talk to your physician about your medications and any potential food/drug interactions you should be aware of.

What is the most important information I should know about grapefruit interactions?

Grapefruit and grapefruit juice can affect how some bipolar medications are metabolized. Always talk to your physician about your medications and any potential food/drug interactions you should be aware of.

Grapefruit can interfere with the metabolism of certain drugs, includingbipolar medications.As a result, eating grapefruit or drinking grapefruit juice when taking these medications can inadvertently increase their concentration to potentially toxic levels.

Why Grapefruit Juice Affects Drugs

A number ofpsychotropic drugs, including those used to treat anxiety, depression, and psychosis, are among the agents grapefruit juice may interact with.This is because grapefruit contains furanocoumarins, an organic compound that blocks an enzyme that normally breaks down these medications (the CYP3A4 enzyme).

When this enzyme is blocked, the concentration level of the drug in the blood will be higher than expected. This can make the intended effect and side effects of the drug stronger—even dangerous.

Grapefruit and some of the related citrus canirreversiblyinhibit the CYP3A4 enzyme.So, drugs that it affects should not be taken with grapefruit or any of the related citrus, or alternative medications should be prescribed.

While other citrus fruits like pomelos, limes, and Seville oranges also contain furanocoumarins,they haven’t been studied as closely.

Effects of Mixing Grapefruit With Medications

The degree to which grapefruit can affect certain drugs can vary. For some medications, one small glass of juice can result in what would be equivalent to a double or triple dose.

Grapefruit’s effects on drug metabolism can be long-lasting. This fruit can interact with certain drugs anywhere from several hours to three days after ingestion.

Although it is purely speculative to suggest who the most vulnerable patient would likely be, people over 45 years old are the prime purchasers of grapefruit and receive the most prescriptions for drugs.

Medications Grapefruit Can Affect

Lamictal (lamotrigine) is one bipolar medication that does not appear to interact with grapefruit juice. However, it’s always best to check with your prescribing physician or pharmacist to make sure.

While clinically significant events due to grapefruit/drug interactions have been reported with some medications, more research is needed to better understand the severity and risk associated with such interactions.

Before You Mix Grapefruit With Medications

Drugs that will interact with grapefruit have these defining elements:

Always read the medication’s packet insert to understand which interactions can occur. Typically, you can find this in or around the fifth paragraph, where it would read: “Talk with your doctor before including grapefruit or grapefruit juice in your diet while you are taking this medicine.”

Each year, more drugs are identified as having a possible interaction with grapefruit.However, you may still be able to enjoy grapefruit or grapefruit juice if taken according to your physician’s instructions. Alternatively, you may be able to substitute other citrus fruits or drinks to obtain health benefits.

Speak with your care provider and tell them about any medications, substances, or supplements you are currently taking to avoid any potentially dangerous interactions.

Can You Drink Alcohol While You’re on a Medication?

9 Sources

Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Siwek M, Krupa AJ, Woroń J.Interactions between grapefruit juice and psychotropic medications: an update of the literature and an original case series.Exp Opin Drug Metab Toxicol. 2024;20(5):333-345. doi:10.1080/17425255.2024.2352468

U.S. Food and Drug Administration.Grapefruit juice and some drugs don’t mix.

Chretien MC, Bailey DG, Asher L, et al.Drug administration and grapefruit.BMJ Open. 2020;10:e034086. doi:10.1136/bmjopen-2019-034086

National Cancer Institute.Furanocoumarin.

Lilja JJ, Kivistö KT, Backman JT, Lamberg TS, Neuvonen PJ.Grapefruit juice substantially increases plasma concentrations of buspirone.Clinical Pharmacology and Therapeutics.1998;64(6):655-660. doi:10.1016/S0009-9236(98)90056-X

Ellingrod VL.Grapefruit juice and psychotropics: How to avoid potential interactions.Curr Psychiatry. 2015;14(6):60-66.

Bailey DG, Dresser G, Arnold JM.Grapefruit-medication interactions: forbidden fruit or avoidable consequences?.CMAJ. 2013;185(4):309–316. doi:10.1503/cmaj.120951

Greenblatt DJ, Derendorf H.Grapefruit-medication interactions.CMAJ. 2013;185(6):507. doi:10.1503/cmaj.113-2109

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