J. Lundahl et al., RELATIONSHIP BETWEEN TIME OF INTAKE OF GRAPEFRUIT-JUICE AND ITS EFFECT ON PHARMACOKINETICS AND PHARMACODYNAMICS OF FELODIPINE IN HEALTHY-SUBJECTS, European Journal of Clinical Pharmacology, 49(1-2), 1995, pp. 61-67
In this randomised, cross-over study, in nine healthy males given felo
dipine ER 10 mg PO 200 mi grapefruit juice was found to increase the p
lasma levels of felodipine even when the juice was taken 24 hours befo
re the drug. Grapefruit juice drunk simultaneously with and 1, 4, 10 o
r 24 hours before the drug administration resulted in a 32-99% increas
e in mean C-max values of felodipine, relative to concomitant water an
d felodipine intake. The effect on AUC was also significant when juice
was taken up to 10 h before the drug. The effect of the interaction d
ecreased with increasing time between juice and drug intake. All treat
ments produced a significant decrease in diastolic blood pressure and
an increase in heart rate in comparison with morning basal values. The
change in haemodynamic variables was approximately the same after all
treatment combinations. Headache was reported more frequently after t
reatments including grapefruit juice.