Hypothalamic Obesity Following Craniopharyngioma Surgery: A Pilot Trial of Combined Metformin and Diazoxide Therapy

Inclusion Criteria: * Craniopharyngioma at least one year following surgery * Evidence of at least one other endocrinopathy of hypothalamic origin * Stable hormone replacement therapy (with one or more of thyroxine hydrocortisone, DDAVP, sex steroids and GH) * Obesity, defined as weight \>120% Ideal Body Weight (IBW) or BMI \> 27 kg/m2, with normal weight for height before tumour diagnosis and weight gain \>2SD above mean for age for 1 year following tumour treatment (41). * Age 9 -22 years * Minimum of 6 months of standard diet and exercise intervention (run-in period). This was chosen to allow a period of prospective measurements to establish individual baseline slope of change in BMI SDS prior to initiation of active treatment with diazoxide and metformin. Exclusion Criteria: * Contraindications for Metformin or Diazoxide use (history or evidence of cardiac, renal, or progressive hepatic disease , diabetes or hypoxic conditions) * Pharmacologic doses of glucocorticoids or use of other medications known to affect glucose metabolism (e.g. beta-blockers, oral hypoglycemics) * Growth hormone (GH) initiation in the preceding 6 months or planned initiation in the next 6 months (to rule out potential confounding effect of GH on weight / body composition and glucose metabolism). * Use of other weight loss medications * Inability of the family and/or patient to comply with study protocol * Non English speaking