INS and hyperinsulinemic hypoglycemia: Serious hypoglycemia is a major, potentially fatal adverse event caused by insulin secretagogues.1 Previous case reports suggested that calcium-channel blockers (CCBs) might reduce the risk of serious hypoglycemia in patients with hyperinsulinemic hypoglycemia.2,3 However, the association of serious hypoglycemia and CCBs used with insulin secretagogues has remained unclear.