• • Know and identify clinical presentations of toxic alcohols.

• • Understand the differential diagnosis of high anion gap metabolic acidosis.

• • Appreciate the importance of history and clinical findings in establishing methanol toxicity diagnoses, especially in centres where laboratory testing is unavailable.

• • Recognize the value of provincial poison centres in supporting emergency physicians in the diagnosis and management of poisonings and overdoses.

Methanol or ethylene glycol ingestion may result in significant morbidity or death without prompt treatment. Despite traditional and widespread use of intravenous ethanol as an antidote, its safety is not well described. An evaluation of the safety and ease of titrating ethanol infusions is necessary given the availability of an alternative antidote.

To evaluate the safety and ease of titrating ethanol infusions for the treatment of methanol or ethylene glycol ingestion.

We reviewed the hospital records of adults treated with ethanol at The Ottawa Hospital for methanol or ethylene glycol ingestion over a 9-year period. Using a standardized case report form, a single reviewer identified prespecified adverse events that developed after the start of ethanol therapy and classified dose adjustments during ethanol therapy as appropriate or inappropriate based on a priori criteria.

Forty-nine cases of methanol or ethylene glycol ingestion treated with ethanol were included in the analysis, of which 45 underwent hemodialysis, 38 were admitted to the intensive care unit, and 4 died. At least one adverse event was identified in 45 (92%) cases, including 35 (71%) with agitation requiring chemical or physical restraints and 10 (20%) with a depressed level of consciousness treated with intubation. The median number of ethanol concentration measurements per treatment course was 6 (range 0–24), of which only 27% were within the target range of 22 to 30 mmol/L and 47% were below. When measured concentrations were outside the target, the adjustment in ethanol dosing (or lack thereof) was deemed inappropriate 59% of the time, including 69% of the time during hemodialysis.

Based on actual practice in a large academic centre, adverse events occur frequently with intravenous ethanol infusions, and ethanol titration is inefficient. The safety profile and therapeutic drug monitoring considerations for ethanol should be considered when choosing an antidote for methanol or ethylene glycol ingestion.