OBJECTIVE - We assessed four putative bedtime treatments in the prevention of nocturnal hypoglycemia in type 1 diabetes.

RESEARCH DESIGN AND METHODS - Plasma glucose concentrations were measured every 15 min from 2200 h through 0700 h in 21 patients with type 1 diabetes (mean±SD. HbA_1C=7.1 ± 1.0%) on five occasions with, in random sequence, bedtime (2200 h) administration of 1) no treatment, 2) a snack, 3) the snack plus the -glucosidase inhibitor acarbose, 4) an uncooked cornstarch bar, or 5) the ₂-adrenergic agonist terbutaline.

RESULTS - In the absence of a bedtime treatment 27% of the measured nocturnal plasma glucose concentrations were <70 mg/dL (3.9 mmol/L) in 12 patients; 16%, 6% and 1% were <60, <50 and <40 mg/dL (3.3, 2.8 and 2.2 mmol/L) respectively. Neither the snack (without or with acarbose) nor cornstarch raised the mean nadir nocturnal glucose concentration or reduced the number of low glucose levels or the number of patients with low levels. Terbutaline raised the mean nadir nocturnal glucose concentration (mean±SE 127 ± 11 vs. 75 ± 9 mg/dL, P < 0.001), eliminated glucose levels <50 mg/dL (P = 0.038), reduced levels <60 mg/dL (P = 0.005) to one and reduced levels <70 mg/dL (P = 0.001) to five (four at 2215 h, one at 2230 h). However, it also raised glucose levels the following morning.

CONCLUSIONS - Nocturnal hypoglycemia is common in aggressively treated type 1 diabetes. Bedtime administration of a conventional snack or of uncooked cornstarch does not prevent it. That of terbutaline prevents nocturnal hypoglycemia but causes hyperglycemia the following morning. The efficacy of a lower dose of terbutaline remains to be determined.