A boxed warning concerning lactic acidosis has been added to the label for Metformin Hydrochloride, effective 2026-05-13. This significant label revision highlights the potential for serious adverse events, including death, hypothermia, hypotension, and resistant bradyarrhythmias, associated with metformin use.
Background
Metformin Hydrochloride is a widely prescribed oral antihyperglycemic agent used in the management of type 2 diabetes mellitus. It belongs to the biguanide class of drugs and primarily works by decreasing hepatic glucose production, decreasing intestinal absorption of glucose, and improving insulin sensitivity by increasing peripheral glucose uptake and utilization. Lactic acidosis is a known, albeit rare, serious complication associated with metformin therapy, particularly in patients with predisposing conditions such as renal impairment, congestive heart failure, or acute illness.
What this means
The addition of a boxed warning to the Metformin Hydrochloride label underscores the critical importance of clinician awareness regarding the risk of lactic acidosis. Prescribing healthcare professionals must carefully assess patient risk factors and monitor for symptoms, which can be subtle in onset. Patient education on the signs and symptoms of lactic acidosis is also crucial. This label change reinforces the need for vigilance in patient selection, ongoing monitoring, and prompt recognition and management of this potentially fatal adverse event.
Source
The information regarding this label revision was obtained from the FDA, specifically a label revision document for Metformin Hydrochloride, effective 2026-05-13, available on dailymed.nlm.nih.gov.