A Boxed Warning concerning lactic acidosis was added to the label for Metformin Hydrochloride, effective 2026-06-17. This warning highlights postmarketing cases of metformin-associated lactic acidosis, which have resulted in death, hypothermia, hypotension, and resistant bradyarrhythmias.
Background
Metformin Hydrochloride is a widely used medication, often prescribed for the management of type 2 diabetes. It is also a component in combination therapies, such as canagliflozin and metformin hydrochloride (Invokamet, Invokamet XR), which combine an SGLT2 inhibitor with metformin.
What this means
The addition of a Boxed Warning for lactic acidosis to the Metformin Hydrochloride label emphasizes the serious nature of this adverse event. Clinicians prescribing Metformin Hydrochloride, either as a monotherapy or as part of combination drugs like Invokamet, must be vigilant for symptoms of lactic acidosis, including hypothermia, hypotension, and resistant bradyarrhythmias. The warning indicates that the onset of metformin-associated lactic acidosis is often subtle, necessitating a high index of suspicion, especially in patients with predisposing factors such as renal impairment, concomitant use of certain drugs, or conditions leading to hypoperfusion and hypoxemia. Patient education regarding the signs and symptoms of lactic acidosis is also crucial.
Source
The information regarding this label revision was obtained from the FDA, as documented on DailyMed. The revised label for Metformin Hydrochloride became effective on 2026-06-17, and is accessible via dailymed.nlm.nih.gov.