When grapefruit and medicine don’t mix

You probably already know that if you take certain medications with certain other medications, an unwanted interaction between the two can occur. But you may not be aware that food also can affect the way some medications work, with grapefruit (including grapefruit juice) posing a major concern when it comes to some drugs.

The trouble with grapefruit

Other fruit juices—even those that are citrus-based—appear to be safe to take with medicine, so why is grapefruit such a troublemaker? The problem can be traced to a group of enzymes (proteins that trigger chemical reactions in the body) that are involved in the way the body processes grapefruit. This particular enzyme group, called P-450, also is involved in the way a number of important medicines are processed. Grapefruit interferes with the way a specific enzyme in the P-450 group operates, and this interference causes the blood to absorb more of the drug than it otherwise would. In other words, if you eat a grapefruit or drink its juice while taking a certain medication, the medication will enter your body more quickly. That, in turn, may lead to negative side effects from the drug.

These unwanted interactions can occur up to 3 days after consuming grapefruit. Even a little bit of grapefruit or grapefruit juice may cause an undesirable interaction.

Overcoming “the grapefruit factor”

If you enjoy consuming grapefruit, you may not have to give it up. First, ask your doctor if any of the medications you’re taking are affected by grapefruit intake. Grapefruit doesn’t cause an interaction with every drug. In fact, in many cases it’s just a single brand of a drug that isn’t compatible with the fruit. For example, one brand of a blood pressure or cholesterol drug may be dangerous to take when you have had grapefruit, but your doctor can prescribe another brand that will be safe for you to use.

From American Family Physician