A suggestive history of ingestion of a toxic dose but no available blood concentration measurements;
Metabolic acidosis and an unexplained elevated osmolar gap (See Diagnosis of Poisoning); or
A serum methanol or ethylene glycol concentration of 20 mg/dL or higher.
Note: Since the introduction of fomepizole (4-methylpyrazole [See Fomepizole (4-Methylpyrazole, 4-Mp)]), a potent inhibitor of alcohol dehydrogenase, most patients with ethylene glycol or methanol poisoning probably will be treated with this drug instead of ethanol, particularly in cases involving small children, patients taking disulfiram, patients with pancreatitis, and hospitals lacking laboratory support to perform rapid ethanol levels (for monitoring treatment). Ethanol is more difficult to dose, requires more monitoring, and has a greater risk of adverse effects. Studies suggest that despite the higher acquisition costs for fomepizole, it may be more cost-effective than ethanol.
Other substances that are metabolized by alcohol dehydrogenase to toxic metabolites include propylene glycol, diethylene glycol, triethylene glycol, glycol ethers (eg, ethylene glycol ethyl ether, ethylene glycol butyl ether), and 1,4-butanediol. The criteria for ethanol therapy and evidence for improved outcomes are lacking for these substances.