A boxed warning concerning the risk of lactic acidosis was added to the label for Metformin Hydrochloride, effective 2026-05-18. This significant label revision highlights the potential for serious adverse events, including death, associated with metformin-associated lactic acidosis.
Background
Metformin Hydrochloride is a widely used medication. A boxed warning, also known as a black box warning, is the strongest warning that the U.S. Food and Drug Administration (FDA) requires for prescription drug products. It is intended to call attention to serious or life-threatening risks associated with the drug.
What this means
The addition of this boxed warning for Metformin Hydrochloride underscores the critical risk of lactic acidosis. The warning states: “WARNING: LACTIC ACIDOSIS Postmarketing cases of metformin-associated lactic acidosis have resulted in death, hypothermia, hypotension, and resistant bradyarrhythmias.” It further notes that “The onset of metformin-associated lactic acidosis is often subtle, accomp”, indicating that clinicians should be vigilant for early signs and symptoms. This change requires healthcare providers to be acutely aware of the risk factors, symptoms, and management strategies for metformin-associated lactic acidosis when prescribing or monitoring patients on Metformin Hydrochloride. Patient education regarding the signs of lactic acidosis is also crucial for timely intervention.
Source
This label revision was issued by the FDA and became effective on 2026-05-18. The information is available through DailyMed, a service of the National Library of Medicine, on dailymed.nlm.nih.gov.