Using miglitol at 30 min before meal is effective in hyperinsulinemic hypoglycemia after a total gastrectomy

A 45-year-old woman who had undergone total gastrectomy for gastric cancer presented with a history of postprandial hypoglycemic episodes with loss of consciousness after meals. Laboratory findings revealed marked hyperinsulinemia and hypoglycemia after a meal. We first treated the patient with octreotide; however, she was unable to continue the treatment because of adverse effects of the drug, such as nausea and headache. Diazoxide was used next for preventing hyperinsulinemia; however, this was not effective for suppressing the postprandial insulin secretion. Since hypoglycemia following gastrectomy is thought to be caused by rapid delivery of nutrients into the duodenum, we performed a meal tolerance test while varying the timing of administration of miglitol in relation to the meal. Miglitol was administered 30 min before, just before, or both 30 min and just before a meal. In the case of administration just before a meal, insulin secretion was suppressed, although hypoglycemia was not prevented. Administration of the drug 30 min before a meal prevented postprandial hypoglycemia by slowing the increase of the blood glucose and serum insulin levels following the meal to a greater degree than administration just before a meal. Miglitol administration both 30 min and just before a meal caused an even smoother increase in blood glucose and serum insulin levels following the meal. In this report, we propose a new therapeutic approach for reactive hypoglycemia after gastrectomy, namely, administration of miglitol 30 min before meals.