title: Hot flashes and fatigue relieved by metformin.
abstract: OBJECTIVE
  To describe 3 patients with long-standing hot flashes, excessive sweating, and fatigue whose symptoms were ameliorated with metformin.
  
  
  METHODS
  In this case series, we report the findings of laboratory evaluations, including assessments for thyroid, gonadal, adrenal, and pancreatic disorders, in 3 patients referred for endocrine evaluation. A 75-g oral glucose tolerance test with measurement of fasting and postprandial glucose and insulin concentrations was conducted. A trial of metformin, 500 mg twice daily, was initiated in all patients.
  
  
  RESULTS
  Evaluation of factors that are associated with hot flashes and increased sweating did not establish the cause of the patients' symptoms. The 3 patients had normal glucose tolerance test results and hyperinsulinemia. Metformin therapy markedly relieved the symptoms in all patients.
  
  
  CONCLUSIONS
  Hyperinsulinemia without hypoglycemia may produce a sympathoexcitatory response that manifests as hot flashes and increased sweating. Metformin may have sympathoinhibitory actions that alleviate these symptoms.
authors.affiliation: Department of Medicine, Division of Endocrinology and Metabolism, University of Louisville School of Medicine, Louisville, Kentucky, USA.
authors.forename: Vinay
authors.initials: V
authors.lastname: Maudar
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Winters
authors.forename: Betty C
authors.initials: BC
authors.lastname: Villafuerte
mesh_terms: D000328:Adult; D004305:Dose-Response Relationship, Drug; D005221:Fatigue / Q000188:drug therapy* / Q000209:etiology; D005260:Female; D019584:Hot Flashes / Q000188:drug therapy* / Q000209:etiology; D006801:Humans; D006946:Hyperinsulinism / Q000150:complications / Q000188:drug therapy; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007333:Insulin Resistance; D008297:Male; D008687:Metformin / Q000627:therapeutic use*; D008875:Middle Aged; D013547:Sweating, Gustatory / Q000188:drug therapy / Q000209:etiology; D016896:Treatment Outcome
chemical_list: D007004:Hypoglycemic Agents; D008687:Metformin