Take caution when combining grapefruit and prescription drugs, study warns

A new study says grapefruit juice can interact with more than 85 oral medications, with almost 45 of them leading to severe, even deadly, consequences. (Handout photo)

TORONTO - Eating a grapefruit or drinking its juice can be a great way to get vitamin C, but it can also be dangerous when taking certain prescription drugs.

A study says grapefruit juice can interact with more than 85 oral medications, with almost 45 of them leading to severe, even deadly, consequences.

Pharmacologist David Bailey of Western University in London, Ont., says adverse effects can include sudden death, acute kidney or respiratory failure, and gastrointestinal bleeding.

Bailey says medications affected by grapefruit include cholesterol-lowering statins, some heart drugs, and certain anti-psychotic and pain medicines.

Grapefruit contains a chemical that interferes with an enzyme that controls how drugs are absorbed through the intestines, resulting in a potentially toxic dose of medication.

Other citrus fruits that contain the chemical to some degree include limes, pomelos and Seville oranges, which are often used in marmalade.

"Many of the drugs that interact with grapefruit are highly prescribed and are essential for the treatment of important or common medical conditions," says Bailey, lead author of the study in Monday's issue of the Canadian Medical Association Journal.