25 Years of Successful Diazoxide and Trichlormethiazide Treatment of Hyperinsulinism in a 79-Year-Old Woman

This paper reports the case of a 79-year-old woman who has been treated for 25 years with diazoxide and trichlormethiazide for continuing hyperinsulinism after an unsuccessful operation for a probable insulinoma. Episodes of confusion and a grand mal seizure associated with hypoglycaemia led to the demonstration of fasting hyperinsulinism [an immunoreactive insulin (IRI): blood glucose (G) ratio of > 0.30 or the ‘amended’ IRI: G ratio of > 49]. Two overnight fasts performed preoperatively and 8 performed postoperatively during the period from 1966 to 1989 confirmed continuing hyperinsulinism causing fasting hypoglycaemia, the need for continuing postoperative therapy, and the ongoing effectiveness of diazoxide and trichlormethiazide. Hyperinsulinism and associated hypoglycaemia have remained well controlled with these agents. Side effects have been minimal despite the long duration of therapy; advancing age has not been a contraindication to therapy. This treatment can be used effectively and safely for prolonged periods without loss of efficacy and without significant side effects in individuals with persistent hyperinsulinism as a result of benign insulinoma.