Lactic acidosis in metformin therapy.

Area of Science:

• Pharmacology
• Metabolic Disorders
• Clinical Medicine

Background:

• Biguanide drugs like metformin and phenformin have been associated with lactic acidosis, a potentially fatal metabolic condition.
• Phenformin was withdrawn due to concerns about its hyperlactataemic effect, but metformin's role has remained less clear.
• Lactic acidosis in patients with diabetes mellitus poses a significant mortality risk.

Purpose of the Study:

• To re-evaluate the association between metformin accumulation and mortality in patients experiencing lactic acidosis.
• To determine if metformin itself contributes to adverse outcomes in lactic acidosis.
• To assess the prognostic significance of metformin levels in patients with lactic acidosis.

Main Methods:

• Retrospective analysis of data from metformin-treated patients who developed lactic acidosis.
• Evaluation of the correlation between metformin plasma concentrations and mortality rates.
• Comparison of mortality rates in patients with varying degrees of hyperlactataemia and metformin accumulation.

Main Results:

• Neither the degree of hyperlactataemia nor metformin accumulation was found to be of prognostic significance in metformin-treated patients with lactic acidosis.
• Patients with high plasma metformin concentrations exhibited the lowest mortality rates.
• Mortality in this cohort was primarily attributed to underlying disease severity rather than metformin toxicity.

Conclusions:

• Metformin is unlikely to be a significant contributor to mortality in patients with lactic acidosis.
• High metformin concentrations may potentially be linked to a beneficial effect, possibly via increased vasomotility.
• These findings suggest a revised understanding of metformin's safety profile in patients with type 2 diabetes mellitus, particularly the elderly, who develop lactic acidosis.