levels exceed 400 to 500 mg/dL Therefore, the sole indication for hemodialysis is hemodynamic instability Treatment is otherwise supportive Methanol Although methanol is used primarily as a solvent for industrial purposes, it is found in other household products, including fuels for stoves, paint removers, and antifreezes Methanol is a model for the few drugs that become more toxic as they are metabolized Although methanol has little or no inherent toxicity, its metabolism by alcohol and aldehyde dehydrogenase to formaldehyde and formic acid creates highly toxic compounds Formic acid is a potent organic acid that results in severe metabolic acidosis and ocular toxicity Ingestions approaching 0.5 to mL/kg of a 100% solution should be considered dangerous The clinical effects of methanol ingestion usually occur after a latent period of to 24 hours This delay occurs as the result of the metabolic conversion of methanol to its toxic by-products In large ingestions, acute methanol poisoning may cause severe CNS depression, metabolic acidosis, and a number of optic changes In the early stages of intoxication, funduscopic examination may be remarkable for hyperemia If left untreated, methanol intoxication results in blindness, with the appearance of a pale, avascular retina In subacute ingestions, the nonspecific neurologic symptoms of methanol intoxication resemble those of ethanol, with a “hangover,” malaise, headache, and dizziness The most immediately significant clinical concern from methanol ingestion is severe metabolic acidosis This acidosis is primarily the result of formic acid production The metabolic acidosis may be intractable and results in multiorgan dysfunction, which includes cardiac arrhythmias, seizures, and pancreatitis The ophthalmologic abnormalities may be temporary or permanent These include blurred or double vision, changes in color perception, and sharply reduced visual acuity Permanent abnormalities may include diminished pupillary light reaction or frank blindness The occurrence of permanent visual defects correlates directly with the degree of metabolic acidosis, the duration of the acidosis, and the quantity of methanol ingested The treatment of methanol ingestion consists of supportive care, administration of specific therapies, and enhancement of elimination Activated charcoal does not adsorb methanol effectively and is unnecessary Laboratory assessment includes serial blood gases, electrolytes, BUN, creatinine, glucose, serum osmolality, and methanol levels Because serum methanol concentrations are only available as “send out” tests at many hospitals,