Hypoglycemia associated with off-label sitagliptin use

PURPOSE: To describe a case of hypoglycemia induced by off-label use of sitagliptin in an adult patient with type 2 diabetes. CASE SUMMARY: Addition of sitagliptin to metformin, glimepiride, and NovoLog(®) 70/30 Mix induced hypoglycemia in a 55-year-old Caucasian female. Hypoglycemia improved, although still occurred periodically, following sulfonylurea discontinuation and a 28% insulin dose reduction. Hypoglycemic symptoms were absent during a 3-day dechallange but occurred again upon sitagliptin reinitiation. DISCUSSION: Although the mechanism of action of sitagliptin does not predispose patients to hypoglycemic events, when combined with hypoglycemia-inducing medications, eg, sulfonylureas or insulin, and possibly meglitinides, the incidence likely increases. CONCLUSIONS: Caution should be used when combining sitagliptin with either sulfonylureas or insulin, and possibly meglitinides, for the treatment of type 2 diabetes as hypoglycemia may ensue. Hypoglycemia due to off-label combinations with insulin and sitagliptin may be prevented by reducing meal-time insulin doses. Prescribers and patients should vigilantly monitor for hypoglycemic events when using sitagliptin off-label with similar pharmacologic combinations such as meglitinides and other rapid-acting insulin products. Additionally, clinicians may encounter resistance from insurance companies to cover such off-label combinations.