Abstract

1. In a single-blind, placebo controlled study the influence of tenoxicam on responses of glucose, insulin and C-peptide to oral doses of glucose and glibenclamide was examined in 16 healthy male volunteers. 2. The subjects received once daily doses of 2.5 mg glibenclamide for 12 days. From day 5 through 12 eight subjects received concomitantly 20 mg tenoxicam once daily and the remaining eight subjects received placebo. 3. On days 1, 4, 5 and 12 glibenclamide was taken with 75 g glucose and blood glucose, serum insulin and C-peptide were measured over 5 h. Plasma levels of glibenclamide and tenoxicam (where appropriate) were followed over 10 h. 4. Characteristic parameters of blood glucose and insulin and C-peptide responses did not change significantly with time (day) and there was no difference between both treatment groups. 5. Baseline insulin increased from 11.7 mu l-1 on day 1 to 15.6 mu l-1 on day 4 (P = 0.009), likewise baseline C-peptide increased from 478 pmol l-1 to 530 pmol l-1 (P = 0.05), but there was no further change in the subsequent treatment period. 6. The AUC of the glibenclamide plasma concentration-time curve did not show changes with time or differences between treatment groups. The mean (s.d.) oral clearance of tenoxicam was 2.5 (1.5) ml min-1 and appeared slightly higher than in previous studies. 7. It was concluded that tenoxicam did not affect overall glycoregulation in healthy subjects under glibenclamide steady state conditions.