Building Competency in Diabetes Education THE ESSENTIALS

TREATMENT MODALITIES: PHARMACOLOGICAL THERAPIES | 6-23

• Severe infection/dehydration, trauma or cardiorespiratory insufficiency, surgery * * Important to review Sick-Day Management Guidelines with all people taking metformin. Temporarily stop during acute illnesses associated with risk for dehydration or procedures associated with high risk of acute kidney injury. Refer to “ Antihyperglycemic agents and sick-day medication” list found later in this chapter. GI side effects can be reduced by starting wih a low initiation dose and slow uptitration (500 mg/day every 1 to 2 weeks) and taking medication with meals (2 largest meals). • 80–85% of glucose-lowering effect is seen with 1,500 mg/day. Maximum effective dose is 2000 mg/day. Higher doses associated with increased risk of adverse events with no additive beneficial effect. Considerations in the elderly ● Do not initiate if eGFR <45 mL/min/1.73m 2 , and/or unstable or acute heart failure at risk of hypoperfusion and hypoxemia. ● Initiate at 500 mg daily and titrate slowly over several weeks to minimize GI side effect. Titrate to the minimum dose needed for glycemic control. ● Rationale: aging is associated with reduced renal function and increased risk of developing lactic acidosis. ● eGFR: 30-45 mL/min/1.73m 2 : Reduce dose to maximum 1,000 mg/day if already taking metformin

Metformin HCL (Glucophage®) • TDD: 250 mg - 2550 mg • Frequency: QD–TID with meals Dosing schedule • Initiate 500 mg twice-daily or 850 mg QD. • Titrate dose by 500 mg/week or 850 mg every 2 weeks. • Usual dose is 500 mg three times a day or 1,000mg twice a day, or 850 mg two or three times a day. • Decrease in FBG levels within 3– 5 days; maximal effect in 1–2 weeks. • Available: 500 mg, 850 mg •

Metformin XR (Glumetza®) Sustained-release metformin • TDD: 500 mg – 2,000 mg • Frequency: QD with meals Dosing schedule • Initiate 500 mg QD or BID • Slow titration by 500 mg/day every 2 weeks • Available: 500 mg, 1,000 mg

• Associated with fewer GI side effects than metformin HCL. • Can increase the frequency of diarrhea.

A1C = glycated hemoglobin; CV = cardiovascular; eGFR = estimated glomerular filtration rate; FBG = fasting blood glucose; GI = gastrointestinal; PCOS = polycystic ovarian syndrome; TDD = total daily dose