Glucose tolerance was improved in an acromegalic patient treated with somatostatin analogue while insulin release was markedly suppressed

While somatostatin analogues (SSAs) are recommended as the first-line therapy for acromegaly, there has been concern over the negative effects of these drugs on glucose tolerance, in particular when patients have diabetes mellitus or impaired glucose tolerance (IGT). A 51-year-old Japanese male who had diabetes mellitus and had been taking glimepiride was diagnosed with acromegaly, and treatment with octreotide LAR was started in March 2007. His plasma levels of GH and IGF-1 decreased almost to normal with the treatment. His HbA1c levels also decreased, and glimepiride was withdrawn after 7 months. 75 g OGTT analyses performed at the diagnosis of acromegaly and 42 months after starting octreotide LAR demonstrated that, although insulin secretion was markedly decreased, glucose tolerance was improved with the treatment. Indeed, the patient was judged to have IGT at the latter time point. Thus, octreotide LAR was effective at controlling not only plasma GH and IGF-1 levels but also the glucose tolerance in our patient, suggesting that SSAs could be chosen as the first-line therapy for acromegaly even when the patient has diabetes mellitus.