Pharmacokinetic observations on piroxicam in young adult, middle-aged and elderly patients.

Nineteen out of 21 patients with painful conditions of the locomotor system aged between 27 and 94 years completed a study in which they received 20 mg piroxicam daily for 14 days. Plasma piroxicam concentrations were estimated by high performance liquid chromatography. Pharmacokinetic analysis of the data showed the half-life and systemic clearance of piroxicam to be unaffected by age. The apparent volume of distribution in older patients was higher than that of younger subjects. Multiple regression analysis showed that creatinine clearance and plasma albumin concentration had insignificant effects on the systemic piroxicam clearance. Although improvement in joint pain and stiffness occurred during the 2 week study period, this could not be correlated with plasma piroxicam concentration.