Update on Grapefruit Juice-Drug Interactions

In February 2012, the Food and Drug Administration (FDA) updated its information about grapefruit juice-drug interactions, including a notice found in new research that grapefruit juice decreases the effectiveness of some drugs. Public Citizen warned readers about the potentially dangerous interactions between grapefruit juice and some prescription and over-the-counter drugs in the February 2004 issue of Worst Pills, Best Pills News. We also warned readers that grapefruit juice-drug interactions cannot be fully avoided by drinking grapefruit juice at a time other than when a medication is taken. The table below lists a total of 82 drugs that can interact with grapefruit juice, resulting in drug levels that are either too high or too low.

Grapefruit juice’s ability to cause potentially toxic blood levels of certain drugs has been known for several decades. Most drug interactions with grapefruit juice result in an increased amount of a certain drug being absorbed into the bloodstream, leading to a higher concentration of the drug in the body and possibly to more adverse drug reactions because of these higher drug levels.

Table 1. Some Drugs That Interact With Grapefruit Juice

* Do Not Use
** Limited Use (offers limited benefits or benefits certain people or conditions)
**** Last-Choice Drug
† Do Not Use Except for Panic Disorder

However, recent research has found that grapefruit juice can also have the opposite effect and can decrease the effectiveness of other drugs. Grapefruit juice does this by blocking natural proteins, called transporters, that are needed for some drugs to be absorbed, resulting in less of these drugs getting into the bloodstream and the body. (Table 1— based in part on an extensive 2010 review that included drugs using the criteria that the medication’s U.S. or U.K. label contained a warning about grapefruit juice — lists some specific drugs that are known to interact with grapefruit juice.)

In its update, the FDA used the popular allergy and hay fever drug fexofenadine (ALLEGRA) as an example of a drug whose effect can be decreased by grapefruit juice. Fexofenadine may also be less effective if taken with orange or apple juice. The drug’s label states, “[D]o not take with fruit juices.”

Other citrus fruits, such as Seville oranges and tangelos, can also result in fruit-drug interactions. If a medication adversely interacts with grapefruit juice, these fruits should also be avoided.

What You Can Do
You should ask your doctor or pharmacist if any of the drugs you are taking interact with grapefruit juice. Also, if you are taking one of the drugs listed in Table 1 and regularly consume grapefruit juice, tell your doctor.

Check your drug’s product label for listed interactions with grapefruit juice.

The FDA consumer update about grapefruit juice interactions can be read in its entirety at www.fda.gov/ForConsumers/ConsumerUpdates/ucm292276.htm.