Drinking grapefruit juice while you're on medication can cause you to overdose, new research has found.

A warning about the relationship between grapefruit and a growing list of popular drugs has been upgraded since research published in the Canadian Medical Association Journal highlighted the serious repercussions.

Because grapefruit contains a chemical that destroys an enzyme in the body that normally breaks down substances like drugs, the meds are made more potent, New Scientist reported.

Drugs can then continue to circulate the body, sometimes triggering an overdose.


David Bailey of the University of Western Ontario conducted the study, which reviewed literature and prescription information of various drugs.

Bailey found that of the 85 drugs known to interact badly with grapefruit, 43 of these can result in serious adverse effects.

The number has increased by 24 per cent since 2008 because of the increasing number of new drugs on the market.

Drinking as little as one glass of juice is enough to spark problems and it can last up to 24 hours, said ABC News chief medical editor Dr Richard Besser.

Drugs affected by the fruit include those taken to treat cancer, sleeping conditions, heart problems, as well as antibiotics and seizure medications, he said.

The most serious known effect is a condition known as torsade de pointes, where the mixing of anti-cancer drugs and grapefruit can result in cardiac arrest and death.

- www.nzherald.co.nz