Interaction of citrus juices with felodipine and nifedipine 
 Six men with borderline hypertension took felodipine 5 mg with water, grapefruit juice, or orange juice.
 The mean felodipine bioavailability with grapefruit juice was 284 (range 164-469)% of that with water.
 The dehydrofelodipine/felodipine AUC ratio was lower, diastolic blood pressure lower, and heart rate higher with grapefruit juice than with water.
 Vasodilatation-related side-effects were more frequent.
 Orange juice had no such effects.
 Six healthy men took nifedipine 10 mg with water or grapefruit juice; the bioavailability with grapefruit juice was 134 (108-169)% of that with water.
