Low-dose bedtime NPH insulin in treatment of secondary failure to glyburide

Secondary failure to oral hypoglycemic agents (OHAs) is a possible outcome for non-insulin-dependent diabetes mellitus (NIDDM) patients and poses a serious therapeutic problem. In this study, we evaluated the effect of adding a single bedtime low-dose NPH insulin injection to the previous ineffective sulfonylurea therapy in 23 NIDDM patients with true secondary failure to OHAs. This treatment schedule was conducted for 3 mo by 18 patients (78%) who completed the study. In these patients, the addition of NPH insulin (0.2 ± 0.01 IU/kg body wt) greatly decreased fasting and postprandial plasma glucose (P < .001) and glycosylated hemoglobin (P < .005). No weight gain was observed in any of the patients studied. Five patients dropped out: 2 patients (9%) due to insufficient compliance, 2 patients (9%) due to the multiple insulin injections required to achieve good metabolic control, and 1 patient (4%) due to recurrent hypoglycemic episodes. No correlation was observed between glucagon-stimulated C-peptide values and amelioration of metabolic control. In conclusion, most NIDDM patients with secondary failure to OHAs may be successfully treated with the addition of a single low-dose bedtime NPH insulin injection, and residual β-cell function evaluation is not able to predict the effectiveness of the combined treatment.