Grapefruit Juice -- and Medication

Before I drink grapefruit juice -- I have to ask my doctor. This is Dr. Steven Andrew Davis, Speaking of Health. The concept is the same but the question has changed. It’s not “doctor, can I drink alcohol while taking this medication?” But, “doctor, can I drink grapefruit juice while on this medicine?” Grapefruit juice can, indeed, affect the metabolism -- the breakdown -- of some drugs enough to affect their effect on the body.

Our understanding of just what’s going between grapefruit juice and medicines has come a long way in the 15 years since it was first described in the medical literature. According to the Medical Letter on Drugs and Therapeutics, grapefruit juice inhibits the activity of an enzyme system which is involved in metabolizing “about half of all drugs currently prescribed.” And the effect can occur even if the drug is taken many hours after the grapefruit juice is drunk. With many of these drugs the action of grapefruit juice on the system increases blood levels of the drugs, leading to possible toxicity. In some studies the blood levels of a mixed bag of drugs, including some used to treat heart and blood vessel disease, allergies, depression, seizures and high cholesterol, were affected, in some way, by grapefruit juice intake of1 to 3 glasses a day for three days in a row.

Clearly, grapefruit and its juice have many health benefits -- and I like Texas Rio Stars the best. But for drugs that require careful control of serum concentrations, it’s best to check with the prescribing doctor to see if grapefruit juice is a “yes” or a “no.” speaking of Health, I’m Dr. Steven Andrew Davis, for CBS News.

Ref: Medical Letter on Drugs and Therapeutics. Vol 46. Jan 5, 2004. Pg. 3-4.

E-Mail drdavis@davishealth.com