Blood pressure-lowering effect of adding grapefruit juice to nifedipine and terazosin in a patient with severe renovascular hypertension.

Grapefruit juice had been fortuitously noted to elevate the concentration of felodipine in a pharmacological study of the effect of ethanol on felodipine. This effect was later confirmed not only for felodipine but also for three other dihydropyridine calcium channel blockers. I herein present what I believe to be the first case report describing a marked blood pressure-lowering effect of grapefruit juice in a person receiving an antihypertensive regimen of a dihydropyridine calcium channel blocker (nifedipine) and terazosin.