Enhanced elimination

Indications for intermittent haemodialysis in patients with methanol or ethylene glycol poisoning are:

• confirmed ingestion of a toxic dose
• metabolic acidosis
• acute kidney injury
• serum methanol or ethylene glycol concentration more than 50 mg/dL (15.6 mmol//L for methanol, 8.07 mmol/L for ethylene glycol).

Antidotal therapy with ethanol or fomepizole increases the half-life of methanol to about 50 hours and ethylene glycol to about 20 hours. Haemodialysis may be indicated after commencing antidotal therapy to eliminate methanol or ethylene glycol and their toxic acid metabolites.

If intermittent haemodialysis is required, transfer the patient to a hospital with an intensive care unit that can provide it. If intermittent haemodialysis is inaccessible, high-flux continuous veno-venous haemodialysis or sustained low-efficiency dialysis may be considered; however, clearance of methanol and ethylene glycol, and their toxic acid metabolites, may be slower using these methods.

Haemodialysis should be continued until metabolic acidosis has resolved and the serum methanol or ethylene glycol concentration is less than 20 mg/dL (6.24 mmol/L for methanol, 3.23 mmol/L for ethylene glycol).

Haemodialysis also removes the antidotes, ethanol and fomepizole, so larger doses of these drugs are required during haemodialysis.

For more information on haemodialysis, see here.