fasting with diabetes mellitus

Indications

• fasting for procedures
• regious reasons

Management

• overnight fasts
  • get fasting labs done prior to 9 AM
  • hold oral hypoglycemic agents & short-acting insulin until eating
  • not necessary to discontiune metformin, glitazones, incretin mimetics, or gliptins since these agents by themselves seldom cause hypglycemia
• fasts longer than overnight
  • hold oral hypoglycemic agents the evening prior to & during the fast
  • hold short-acting insulin while fasting
  • consider reducing dose of long-acting insulin by 1/3 to 1/2
• diabetes mellitus type 1
  • do NOT stop basal insulin.
  • some insulin is still needed during fasting to prevent diabetic ketoacidosis
• diabetes mellitus type 2
  • supervised fasting could eliminate the need for insulin in some patients with type 2 diabetes
• Ramadan
  • patients fast during the day & eat only at night
  • consider switching to QHS or once a day evening dosing of hypoglycemic agents during Ramadan
  • discourage fasting if
    • pregnant
    • acutely ill
    • diabetes mellitus is poorly controlled
• stop fast if blood glucose < 70 mg/dL

More general terms

• fasting