Furanocoumarins In Grapefruit Interact Dangerously With Some Medications

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Furanocoumarins In Grapefruit Interact Dangerously With Some

Medications

http://www.medicalnewstoday.com/healthnews.php?newsid=43420

According to new research, it is not the flavonoids in grapefruit

that interact dangerously with some drugs, it is the furanocoumarins.

Some medications, such as those for cholesterol and hypertension, are

affected by furanocoumarins so that they enter the bloodstream too

quickly.

You can read about this study in the American Journal of Clinical

Nutrition.

There is an enzyme in our intestine which destroys a quantity of some

drugs, thus slowing down the amount entering the bloodstream.

Furanocoumarins inhibit the enzyme, thus more of the drug enters the

bloodstream.

Patients on some medications have to avoid grapefruit juice. Others

take grapefruit juice in order to get more of the drug into their

system. It depends which drug the patient is on.

Researchers at the University of North Carolina at Chapel Hill, USA,

proved that furanocoumarins were the culprits, not flavonoids. They

did this by giving volunteers two types of grapefruit juice. One had

furanocoumarins in it, while the other didn't - it had been taken

out.

The volunteers were divided into three groups. They were all given 10

milligrams of Felodipine, a hypertension drug. One group consumed

fresh orange juice, another had normal fresh grapefruit juice, and

the third group had grapefruit juice with the furanocoumarins

removed.

After a series of blood tests the researchers found that the

absorption rate of the drug into the bloodstream had been altered by

the regular grapefruit juice group only - the group that was given

grapefruit juice with the furanocoumarins left in.

Dr. Watkins, one of the researchers, said that this study gives

clear evidence that furanocoumarins interacted with the drug in a way

that accelerated the rate at which it entered the bloodstream. When

they got rid of the furanocoumarins from the grapefruit juice, the

interaction was not present.

Perhaps, for patients on such medications who wish to continue

drinking grapefruit juice, makers should consider making this juice

with the furanocoumarins removed, said the researchers. They added

that it would be plausible to screen foods for the presence of

furanocoumarins.

Furanocoumarins could also be useful in helping some drugs to enter

the bloodstream more easily - some orally administered drugs.

See the abstract in the American Journal of Clinical Nutrition A

furanocoumarin-free grapefruit juice establishes furanocoumarins as

the mediators of the grapefruit juice-felodipine interaction