Fruit juices harmful for patients taking drugs

Toronto, Aug 21 : Drinking juices while taking prescription drugs is not advisable for patients, according to a Canadian study.

The study, which was carried out by David Bailey of the University of Western Ontario near here, says that drinking fruit juice while taking certain drugs decreases their absorption and potentially wipes out their beneficial effects.

Bailey, who is professor of clinical pharmacology at the university and leader of the study, said Wednesday that common fruit juice like grapefruit, apple and orange can have adverse effects on certain drugs, including those prescribed for fighting life-threatening conditions such as heart disease, cancer, organ-transplant rejection, and infection.

'This is just the tip of the iceberg. I'm sure we'll find more and more drugs that are affected this way," he said.

During their study, Bailey and his team found that only half of Fexofenadine, used to fight allergies, was absorbed when taken with grapefruit juice compared to when it was taken with water alone.

"We discovered that grapefruit and these other fruit juices substantially decrease the oral absorption of certain drugs undergoing intestinal uptake transport.

"The concern is loss of benefit of medications essential for the treatment of serious medical conditions," said Bailey.

Losing half of the amount of drugs taken into the body can be critical for the performance certain drugs, said Bailey.

The team found that grapefruit juice blocked a key drug transporter that shuttles drugs from the small intestine to the bloodstream, reducing drug absorption and neutralising their potential benefits.

During their research, the team also found that drugs whose levels are boosted in the presence of grapefruit juice appear to block an important drug metabolizing enzyme.

A veteran researcher, Bailey had announced 20 years ago that grapefruit juice can lead to dramatically dangerous concentrations of the high-blood-pressure drug Felodipine in the blood.

Since then, he and fellow researchers have identified nearly 50 drugs which cause what they call the "grapefruit juice effect."

These drugs include certain antibiotics, high blood pressure drugs, beta blockers and anti-cancer agents.

The study was presented Tuesday at the 236th National Meeting of the American Chemical Society in Philadelphia.