A new study has found drinking grapefruit, orange or apple juice while taking certain drugs can wipe out any beneficial effects of the medications.
It is believed to be "a brand new type of food-drug interaction," study leader Dr. David Bailey of the University of Western Ontario told 愛污传媒.
In the study, which was presented at a meeting of the American Chemical Society, researchers gave patients the popular allergy drug Allegra.
The drug was found to work normally in those who took it with water, but it had barely any effect when it was taken with grapefruit juice.
"Only a half to a third of the medication was actually absorbed," said Dr. George Dresser of Victoria Hospital in London, Ont.
There are concerns that the juices could have the same effect in patients taking drugs essential to treating medical conditions like heart disease, cancer and infection.
While earlier studies found the 'Grapefruit Juice Effect' could increase the absorption of certain drugs and lead to overdoses, this new evidence shows it can have the opposite effect on other drugs.
Bailey added that at the moment there is no complete list of which specific drugs will have this type of interaction.
To date, researchers have found the juice can lower the absorption of drugs used to treat cancer and high blood pressure, prevent heart attacks and rejection of transplanted organs, and some antibiotics.
Researchers are urging concerned patients to consult their doctor.
According to Bailey, "The best thing would be to take your medication with water two hours before consuming fruit juices, to prevent or reduce the chance of this drug interaction."
Apple and orange juice contain substances similar to the active ingredient in grapefruit juice, meaning they likely have a similar effect, and Dresser is concerned that the effect may not be limited to juice.
"I think that this is the tip of the iceberg," he said. "I think that there may be many other types of foods that could also possibly cause an interaction."
With a report from CTV medical specialist Avis Favaro and senior producer Elizabeth St. Philip
