Risk of Metformin in Hospitalized Patients

Primary Risks and Recommendations

The American Diabetes Association recommends temporary discontinuation of metformin during hospitalizations and acute illness that may compromise renal or liver function 2
The Lancet Diabetes and Endocrinology guidelines explicitly recommend avoiding metformin in hospitalized patients at risk for lactic acidosis, including those with anaerobic metabolism, impaired metformin clearance, or impaired lactate clearance 1
Hospitalized patients face dynamic clinical conditions that can rapidly create risk factors for lactic acidosis, including acute kidney injury from sepsis, hypotension, or contrast procedures 1
A COVID-19 study showed inpatient metformin use was associated with increased lactic acidosis risk, particularly with higher doses, worse kidney function, and greater disease severity 1

Basal insulin with correctional rapid-acting insulin is the preferred approach for hospitalized patients, even those with good oral intake 4
Sitagliptin has been studied as a safe alternative in hospitalized patients with mild-to-moderate hyperglycemia and good oral intake 4

The default position should be to discontinue metformin on hospital admission 1, 2, 3
If considering continuation, ensure eGFR ≥45 mL/min, no acute illness, and daily monitoring of renal function and lactate 1, 3