Methanol toxicity. Agency for Toxic Substances and Disease Registry.

Methanol is used in a variety of commercial and consumer products. Increased use of methanol as a motor fuel may lead to higher ambient air levels and a greater potential for ingestion from siphoning accidents. Methanol toxicity initially is not characterized by severe toxic manifestations. Pathophysiologically, methanol toxicity represents a classic example of "lethal synthesis," in which toxic metabolites can cause fatality after a characteristic latent period. Methanol is well absorbed following inhalation, ingestion or cutaneous exposure. It is oxidized in the liver to formaldehyde, then to formic acid, which contributes to the profound metabolic acidosis occurring in acute methanol poisoning. The metabolic products of methanol can produce a syndrome of delayed-onset acidosis, obtundation, visual disturbance and death. Intravenous sodium bicarbonate therapy should be considered if the patient's blood pH is below 7.2. Symptoms and history determine whether intravenous ethanol therapy and hemodialysis should be instituted.