Methanol poisoning is not common and is usually accidental. Methanol is metabolized at one-fifth the rate of ethanol, making it more toxic. Acute methanol poisoning is characterized by weakness, nausea, vomiting, headache and epigastric pain, but not typically inebriation. Metabolic acidosis occurs. The toxic metabolites damage the retina, and permanent blindess may result from ingestion of only 10 mL, while fatalities occur with as little as 30-60 mL. Lethal blood levels occur at 0.08% (80 mg%). Administration of fomepizole (an inhibitor of alcohol dehydrogenase) or ethanol as a competitive binder to the enzyme, is used to treat methanol poisoning.