What Is the Treatment for Methanol Poisoning?

Treatment for methanol poisoning typically involves removing and neutralizing the methanol still in the stomach, neutralizing metabolic acidosis and preventing the remaining methanol from being broken down, and removing the un-metabolized methanol and any remaining methanol metabolites. When methanol is ingested, the body breaks down the compound into toxic parts or metabolites which causes metabolic acidosis, and blood and other body fluids become highly acidic. Metabolic acidosis can be fatal if not treated quickly.

If a patient is discovered soon after ingesting methanol, quick action can be performed by the emergency response team to remove any methanol still in the stomach by inducing vomiting or pumping out the poison. Activated charcoal, a fairly universal poison neutralizer, is often administered, although this is not an evidence-based practice. Unfortunately, activated charcoal is not particularly effective at absorbing methanol, or other alcohols. Any methanol that was digested by the stomach or reached the digestive tract before the stomach pumping will be broken down and begin to poison the body.

The second stage of treatment for methanol poisoning is to neutralize the metabolic acidosis caused by the metabolism of methanol to formic acid. Diagnosis of metabolic acidosis is difficult unless methanol poisoning is suspected because symptoms are fairly general and include vomiting, chest pain, heart palpitations, and an anxious mental state. Treatment begins by performing an arterial blood gas to test the body's pH level, or how acidic the blood is, and the bicarbonate level, or the ability of the blood to buffer against elevated acid levels. To neutralize the elevated acid level, sodium bicarbonate will be administered intravenously to regulate the pH balance, and folinic or folic acid will be given to help metabolize the formic acid. The patient will often be given intravenous fluids and electrolytes, airway management, and be evaluated and treated for any existing neurological or cardiovascular problems resulting from the methanol poisoning.

In the third stage of treatment, the goal is to prevent further metabolism of the methanol and to remove unmetabolized methanol and any remaining toxic metabolites. Alcohol dehydrogenases are enzymes which catalyze the breakdown of alcohols and, in the case of methanol poisoning, allow for the breakdown of methanol to formic acid. Ethanol or fomepizole are typically administered to prevent the metabolism of methanol because they act as competitive inhibitors to alcohol dehydrogenases, meaning they bind to alcohol dehydrogenases and leave them inactive and useless. As a result, ethanol or fomepizole prevents or slows the metabolism of methanol into its toxic byproducts, allowing methanol to be eliminated through the kidneys. Hemodialysis will also be performed to clear the blood of any methanol and formic acid still remaining.