Effect of Grapefruit Juice on Clarithromycin Pharmacokinetics

To investigate whether grapefruit juice inhibits the metabolism of clarithromycin, 12 healthy subjects were given water or grapefruit juice before and after a clarithromycin dose of 500 mg in a randomized crossover study. Administration of grapefruit juice increased the time to peak concentration of both clarithromycin (82 ± 35 versus 148 ± 83 min; P = 0.02) and 14-hydroxyclarithromycin (84 ± 38 min versus 173 ± 85; P = 0.01) but did not affect other pharmacokinetic parameters.