Inhalational abuse of methanol products: elevated methanol and formate levels without vision loss

Inhalant abuse of methanol-containing products has increased over the last decade. We performed a prospective observational study of 7 subjects who presented to an ED after inhalant abuse of methanol-containing hydrocarbon products. Four patients had a methanol level greater than 24 mg/dL and 2 had an anion gap greater than 17 mEq/L. The mean formic acid level was 71 microg/mL, and 1 patient had a level considered high enough to induce retinal toxicity (>200 microg/mL). No patient had an abnormal ophthalmologic examination. All patients were treated with intravenous folate, 2 received alcohol dehydrogenase blockade, and no patient received hemodialysis or intravenous bicarbonate. All patients' acidosis resolved within 4 hours. The methanol and formic acid levels are lower than those reported after methanol ingestion. These preliminary data suggest that inhalant abusers of methanol products may have significantly elevated methanol and formic acid levels, but are at low risk for methanol induced complications of visual dysfunction and refractory acidosis.