Ibuprofen: plasma concentrations in man.
The plasma levels of ibuprofen were measured in five healthy subjects who took 600 mg tablets of ibuprofen twice daily, three times daily and four times daily in a crossover study. Peak plasma levels were obtained 1 hour after the first dose in all but one subject (slow absorber), the mean peak value being 51.3 micrograms X ml-1 (range 39.4-63.7 micrograms X ml-1). After the repeated dose regimens of two, three or four times daily of ibuprofen, the peak levels achieved were in a similar range to those seen after the first dose: Twice daily 39.4-66.4 micrograms X ml-1; Three times daily 43.6-63.3 micrograms X ml-1; Four times daily 44.1-58.4 micrograms X ml-1. There was no evidence of accumulation of the drug and no side-effects occurred during the trial.