Treatment of NIDDM patients with secondary failure to glyburide: comparison of the addition of either metformin or bed-time NPH insulin to glyburide.

In this study we compared, in 12 NIDDM patients with secondary failure to glyburide, the effect of adding either a single, low-dose bed time NPH insulin injection (0.2 U/Kg) or an oral metformin administration (500 mg x 3) to the previously ineffective sulfonylurea treatment. The addition of both insulin and metformin treatment significantly improved fasting plasma glucose, post-prandial plasma glucose and %HbA1. The effect of both combined therapies was already evident and maximal after 2 weeks of treatment. The addition of bed-time NPH insulin caused a greater decrease of fasting plasma glucose, although the difference with the addition of metformin was not significant. In contrast, the average post-prandial plasma glucose decrease was significantly greater after metformin addition. The addition of bed-time NPH insulin caused a significant increase in average body weight, while after metformin addition, average body weight was unchanged; no change in the average cholesterol and triglyceride level was observed after either combined therapies.