Premium
Effect of grapefruit juice on carbamazepine bioavailability in patients with epilepsy
Author(s) -
Garg Santosh K.,
Kumar Naresh,
Bhargava Vinod K.,
Prabhakar Sudesh K.
Publication year - 1998
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1016/s0009-9236(98)90177-1
Subject(s) - carbamazepine , grapefruit juice , bioavailability , crossover study , chemistry , pharmacology , pharmacokinetics , cyp3a4 , epilepsy , high performance liquid chromatography , chromatography , medicine , metabolism , biochemistry , cytochrome p450 , alternative medicine , pathology , psychiatry , placebo
Objectives To examine the effect of grapefruit juice on the bioavaiability of carbamazepine in patients with epilepsy. Methods This was a randomized crossover study consisting of 2 phases. Ten patients with epilepsy who had received therapy with 200 mg carbamazepine 3 times a day for the previous 3 to 4 weeks participated. They were given either grapefruit juice or 300 mL water at 8 AM along with 200 mg carbamazepine. Each treatment was separated by 2 days; subjects continued to receive carbamazepine therapy during the 2‐day period. On both occasions, blood samples were collected at different time intervals between 0 to 8 hours. Carbamazepine levels were estimated by reversed‐phase HPLC technique. Results Compared with water, grapefruit juice significantly increased the steady‐state peak concentration (6.55 versus 9.20 μg/mL), trough concentration (4.51 versus 6.28 μg/mL), and area under the plasma concentration‐time curve (43.99 versus 61.95 μg · h/mL) of carbamazepine. No significant effect was found in the time to reach peak plasma concentration. Conclusion Grapefruit juice increases the bioavailability of carbamazepine by inhibiting CYP3A4 enzymes in gut wall and in the liver. Clinical Pharmacology & Therapeutics (1998) 64 , 286–288; doi: