Pharmacokinetic projections for isoxicam and piroxicam in old and young subjects.

A single-dose pharmacokinetic study to determine the effect of age on the disposition of isoxicam and piroxicam was carried out on a group of old and a group of young subjects. Although there was no significant difference with either drug in the mean elimination half-time between the group of young and the group of old subjects, there was considerable individual variation. Steady-state levels were calculated to be three times as high in subjects with slow clearance as in those with more rapid clearance. Three weeks would be required with either drug to achieve steady-state drug levels in those subjects with slow drug-clearance.