Medical Treatment for Inoperable Insulinoma: Clinical Usefulness of Diphenylhydantoin and Diltiazem

This report describes a 78-year-old woman with insulinoma, treatedwith a combination of diphenylhydantoin and a calcium antagonist.The effectiveness of 200 mg of diphenylhydantoin and 180 mgof diltiazem was evaluated by measuring the levels of plasmaglucose, immunoreactive insulin and immunoreactive insulin/plasmaglucose after fasting or by the oral glucose tolerance test,and by the appearance of hypoglycemic symptoms. The mean concentrationof fasting plasma glucose increased significantly during thetreatment. The levels of immunoreactive insulin/plasma glucoseand C-peptide imniunoreactivity/plasma glucose significantlydecreased. Symptomatically. no episode of hypoglycemia was notedduring the combined treatment.