Grapefruit Juice Can Block Calcium Chanel Blockers
Tuesday October 3, 2006
1 in 5 people drink grapefruit juice everyday. Grapefruit juice can interfere with many common medicines. This problem is often not mentioned by doctors. If you are taking calcium blockers to control high blood pressure, you should be wary of grapefruit juice. A recent article on MedicineNet reported that grapefruit juice can block the effects of many common medicines including calcium channel blockers.


Comments
Grapefruit juice does not block the effect of calcium channel blockers – it increases the effect! Components of the juice can block the metabolism (break down) of some calcium channel blockers which leaves more active drug and increases the effect of the calcium channel blocker.
See the article quoted:
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.