The effects of age and gender on the pharmacokinetics of tenidap sodium in patients with rheumatoid arthritis and osteoarthritis.

1. This open-label study was conducted to evaluate the effects of age and gender on the pharmacokinetics of tenidap sodium in patients with either rheumatoid arthritis (RA) or osteoarthritis (OA). 2. A total of 145 male and female patients, 80 with RA (aged 22-91 years) and 65 with OA (aged 45-83 years) each received a single dose of 120 mg tenidap sodium. Pharmacokinetic parameters were estimated from individual tenidap plasma concentration-time curves determined up to 120 h post-dose. Tenidap plasma protein binding was determined in the youngest and oldest age groups for both RA and OA patients. 3. In RA patients, age and gender did not significantly affect the disposition of tenidap or the percentage of unbound tenidap in plasma. Only for tmax were statistically significant effects in the analysis of covariance observed and these were attributed to very high tmax values in two female patients. Likewise, in patients with OA, age and gender did not significantly affect the pharmacokinetics of tenidap, although patients with larger body weights had lower Cmax values. 4. Pharmacokinetic parameters were not significantly different between RA and OA patients, except for t1/2, where two outlier RA patients had low values that caused the mean value to be significantly lower in RA (24 h) than in OA (26 h) patients. Pharmacokinetic parameters for pooled values from RA and OA patients were as follows: t1/2 = 25 h, AUC = 538.4 micrograms ml-1 h, Cmax = 21.9 micrograms ml-1, tmax = 3.2 h.(ABSTRACT TRUNCATED AT 250 WORDS)