Hypoglycemic effect of disopyramide in a case of diabetes mellitus under insulin treatment.

In a 41-year-old male with diabetes mellitus well controlled with insulin (50 units/day), hypoglycemia developed after starting disopyramide treatment (200 mg/day) for correction of tachycardia. Lower levels of blood glucose and smaller amounts of urinary sugar persisted until disopyramide was withdrawn even after reducing insulin to a minimum dose of 20 units/day. The insulin requirement increased again thereafter to the original dose. These results indicate that disopyramide had a hypoglycemic effect in this patient.