Grapefruitjuice and Drug Absorbtion

[Guest guest]

Is this the same ingredient in grapefruit juice that enhances the effect

of Gleevec? Good news for grapefruit juice lovers.

Zavie

WASHINGTON (Reuters) - U.S. researchers said they have

identified the compound in grapefruit juice that

affects how some drugs are absorbed in the body and

said on Tuesday it might be used to help lower dosages

for some patients

Grapefruit juice is known for its effects on drug

metabolism and is avoided by some patients while other

deliberately take their drugs with the juice.

The reason is an intestinal enzyme called CYP3A, which

partially destroys drugs as they are absorbed.

Grapefruit juice, like no other fruit juice,

interferes with CYP3A, so the body ends up absorbing

more of the drug.

Dr. Watkins of the University of North Carolina

at Chapel Hill and colleagues say they have identified

the substance in grapefruit juice that is responsible

-- furanocoumarin.

" It should now be possible to market the

furanocoumarin-free grapefruit juice to patients who

would otherwise need to avoid grapefruit, " Watkins

said in a statement.

" In addition, it should be possible to screen new

foods for the potential for drug interactions by

determining whether they contain furanocoumarins, "

Watkins said.

" Finally, it may be possible to add furanocoumarins to

formulations of certain drugs that tend to be poorly

or erratically absorbed to improve their oral

delivery. "

To test the theory that furanocoumarin was the

responsible compound, Watkins and colleagues filtered

it out grapefruit juice, which they discovered was

then less bitter but otherwise unaltered.

Then they tested 18 men and women taking various drugs

on a regular basis including aspirin and birth control

pills.

Each fasted in the hospital and got a single dose of

the blood pressure drug felopidine, sold under the

brand name Plendil, along with either normal

grapefruit juice, furanocoumarin-free juice or orange

juice.

They then ate and drank normally and blood was taken

regularly all day.

In each volunteer, the normal grapefruit juice made

between 6 percent to 230 percent more Plendil

available in the blood, the researchers reported in

the American Journal of Clinical Nutrition. The

furanocoumarin-free grapefruit juice and orange juice

had no such effect, they reported.