Grapefruit and medication interaction

Men of a certain age may recall a time when the neighborhood druggist used a mortar and pestle to formulate medications on the spot. That practice is nearly extinct in the United States, where today's pharmacies dispense complex medications manufactured according to exacting standards. And few pharmacies could function without a computer to keep track of your medications, your allergies, and your billing information. Since you may need a large number of drugs, the computer also checks for drug interactions that could be harmful. It will also warn you whether you should avoid alcohol, and it will note whether you should take your pills with meals or on an empty stomach. It's great progress, but there's another important issue to consider: the interaction between certain foods and medications.

Grapefruit is a case in point. Grapefruit and grapefruit juice are healthful, providing enough vitamin C, potassium, dietary fiber, and other nutrients to earn the American Heart Association's "heart-check" mark. It's also tasty, which is why 21% of all households in the United States buy grapefruit juice and 14% of all American men drink it regularly. That's the good news. The bad news is that grapefruit juice can interact with dozens of medications, sometimes dangerously.

Doctors are not sure which of the hundreds of chemicals in grapefruit are responsible. The leading candidate is furanocoumarin. It is also found in Seville (sour) oranges and tangelos; although these fruits have not been studied in detail, the guidelines for grapefruit should apply to them as well.

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