Lactic acidosis is a rare, but serious, metabolic complication that can occur due to metformin accumulation.

Avandamet is metformin and rosiglitazone; Glucovance is metformin and glyburide; Invokamet is metformin and canagliflozin; Janumet is metformin and sitagliptin; Synjardy is metformin and empagliflozin; Xigduo XR is metformin and dapagliflozin.

In June 2022, the UK Medicines and Healthcare products Regulatory Agency (MHRA) published advice, stating that low vitamin B12 is now considered to be a common side effect of metformin. The MHRA advises checking levels in patients with symptoms of B12 deficiency, as well as monitoring those at risk of B12.

LACTIC ACIDOSIS

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Page last updated 05/11/2026

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Incidence - Help

<1% 1‑5% 5‑10% 10‑15% 15‑20% 20‑30% >30%

Seriousness - Help

Hospitalization possible
Life threatening
Fatal

Warnings in other populations - Help

BreastfeedingBreast feeding

GeriatricGeriatric

PediatricPediatric