Insulin sparing effect of hydroxychloroquine in uncontrolled diabetes mellitus

Hydroxychloroquine (HCQ) has a favorable glycemic effect that provides a rationale for its use in diabetes mellitus. Decreased insulin degradation and increased insulin sensitivity is suggested to contribute to the reduction in serum glucose levels. Herein, we present a case on the beneficial impact of HCQ on glycemic control in diabetes mellitus. A 69-year old female suffering from type 2 diabetes mellitus presented to the clinic for routine follow up. For management of diabetes she was taking glimepiride 4mg once daily, combination of metformin and sitagliptin (1000/50 mg) twice daily and 94 units of insulin/day. Baseline fasting plasma glucose (FPG) and postprandial plasma glucose (PPG) levels were 183 and 222 mg/dL respectively and glycosylated hemoglobin A (HbA1c) level was 8.4%. To achieve glycemic control HCQ 400 mg once daily was initiated as an add on antidiabetic drug. HBA1c level decreased to 6.9% at four months and to 6.8% at eight months after HCQ was utilized. FPG level decreased to 110 mg/dL at six months and to 114 mg/dL at eight months. PPG level decreased to 178 mg/dL at six months and 130 mg/dL at eight months. Thus the FPG level decreased by 69 mg/dL and PPG level decreased by 92 mg/dL respectively from baseline. Acknowledging the progressive positive response to antidiabetic agents, the insulin dose was decreased to 56 units/day at four months, 42 units/day at six months and 28 units/day at eight months. The case highlights the potential ability of HCQ to lower HbA1c and decrease insulin requirement in uncontrolled diabetic patients