Comparative efficacy of metformin and glibenclamide in patients with non-insulin-dependent diabetes mellitus

Abstract

Metformin and glibenclamide were compared in a randomized, double-blind trial in patients with non-insulin-dependent diabetes mellitus (NIDDM) using a parallel group design. The study was performed in primary health care, and the main purpose was to assess combination therapy with the two drugs as primary treatment versus conventional oral therapy. After a 2 months diet period patients were randomized to commence treatment with either metformin, glibenclamide or the combination of both. Patients randomized to monotherapy received the alternative drug in addition if the maximal dose i.e. 3 g metformin or 14 mg glibenclamide was insufficient to normalize the fasting blood glucose concentration (FBG). Randomization and dose escalation occurred at FBG greater than or equal to 6.7 mmol/l. The titrated dose was continued for 6 months, whereafter placebo was given for 2 weeks. Seventy-two patients were randomized to either the metformin group (n = 38) or the glibenclamide group (n = 34). Fifty-six completed 6 months treatment, twenty-eight in each randomized group. Glycaemic control was unchanged after diet alone in all groups. The improvement during drug treatment was highly significant (p less than 0.001), mean FBG difference (+/- SEM) 3.2 +/- 0.4 mmol/l and mean HbA1c difference (+/- SEM) 1.5 +/- 0.2% (n = 56). There were no significant differences between patients treated solely with metformin (n = 16) and glibenclamide (n = 17) or between patients treated with a combination of glibenclamide added to metformin (n = 12) and metformin added to glibenclamide (n = 11).(ABSTRACT TRUNCATED AT 250 WORDS)