Grapefruit Juice Can Interact With Medicines!

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A nutraceutical is a food or part of a food that allegedly provides medicinal or health benefits, including the prevention and treatment of disease. Grapefruit juice has been touted as containing many compounds that can reduce hardening of the arteries (atherosclerosis) and even the risk of cancer. Grapefruit juice can, therefore, be justifiably referred to as a classic nutraceutical. However, for many persons taking certain medications, grapefruit juice might actually better be termed a "nutrapollutical!"

It turns out that grapefruit juice can directly or indirectly interact in important ways with a number of medications. This is especially important since grapefruit juice is consumed by approximately one fifth of Americans for breakfast - a time of the day when medications also are commonly taken.

Grapefruit juice blocks special enzymes in the wall of the small intestine that actually destroys many medications and prevents their absorption into the body. Thus, smaller amounts of the drugs get into the body than are ingested. When the action of this enzyme is blocked, more of the drugs get into the body and the blood levels of these medications increase. This can lead to toxic side effects from the medications.

Amazingly, this remarkable food-drug interaction was discovered completely by accident over a decade ago! Researchers were investigating whether alcohol could interact with felodipine (Plendil) and used a solution of alcohol with grapefruit juice to mask the taste of alcohol for the study. Researchers discovered that blood levels of felodipine were increased several fold more than in previous studies. This increased blood level caused an increase in the effect and side effects of felodipine. Further research revealed that the grapefruit juice itself was actually increasing the amount of the study drug in the body.

Medically Reviewed by a Doctor on 7/3/2014