A boxed warning has been added to the label for metformin hydrochloride, effective 2026-05-05. This warning highlights the serious and potentially fatal risk of lactic acidosis, an adverse event observed in postmarketing cases. The condition is characterized by death, hypothermia, hypotension, and resistant bradyarrhythmias, with an often subtle onset.
Background
The updated label for metformin hydrochloride now includes a prominent boxed warning concerning the risk of lactic acidosis. This severe metabolic complication has been reported in postmarketing surveillance of patients using metformin. Lactic acidosis associated with metformin use can manifest with symptoms that are often subtle, making early detection challenging. The warning specifically notes that cases have resulted in serious outcomes including death, hypothermia, hypotension, and resistant bradyarrhythmias.
What this means
The addition of a boxed warning for lactic acidosis on the metformin hydrochloride label signifies a critical update for healthcare providers. This emphasizes the need for heightened awareness regarding the potential for this life-threatening adverse reaction in patients receiving metformin. Clinicians should be particularly vigilant for the often subtle onset of metformin-associated lactic acidosis, which can progress rapidly and lead to severe consequences such as death, hypothermia, hypotension, and resistant bradyarrhythmias. Understanding the characteristics of this condition is crucial for timely diagnosis and management. This label revision reinforces the importance of assessing patient risk factors for lactic acidosis, including renal impairment, concomitant drug use, and other predisposing conditions, to ensure patient safety when prescribing or continuing treatment with metformin.
Source
This information is based on an FDA label revision for metformin hydrochloride, effective 2026-05-05. The details were retrieved from DailyMed, a service of the National Library of Medicine, at dailymed.nlm.nih.gov.