TOXICOLOGY/ADDICTION MEDICINE
Managing Toxic Alcohols: Best Practices and Treatment Strategies By Hayley Gartner, PharmD and Allyson Greenberg, PharmD, on behalf of the SAEM Toxicology and Addiction Medicine Interest Group and the SAEM Academic Emergency Medicine Pharmacists Interest Group
SAEM PULSE | JANUARY-FEBRUARY 2025
Background
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Toxic alcohols are organic compounds containing one or more hydroxyl groups and are not intended for human consumption. The most clinically relevant toxic alcohols are methanol, ethylene glycol, and isopropanol. Methanol is commonly found in products such as windshield washer fluid, cooking fuel, and carburetor cleaner, and may also be present in illicit moonshine. Ethylene glycol serves as a reagent in industrial settings and is the primary ingredient in antifreeze. Isopropanol is used in disinfectants and as a solvent in both industrial and
laboratory environments. Ingestion is the primary route of exposure for all three toxic alcohols. While inhalation exposure is possible with more volatile alcohols like methanol and isopropanol, it rarely leads to toxicity. In some cases, chronic dermal exposure can also lead to toxic effects.
Mechanism of Toxicity
Toxic alcohols can cause intoxication but generally are not directly toxic, except for isopropanol. The toxic effects of methanol and ethylene glycol arise primarily from their organic acid metabolites. Alcohol
dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) are the key enzymes involved in metabolizing these substances. ADH initiates the oxidation of toxic alcohols, producing aldehydes (except for acetone from isopropanol). These aldehydes are then further oxidized by ALDH to yield toxic carboxylic acid metabolites: methanol is converted to formic acid, and ethylene glycol is metabolized to oxalic and glycolic acids. ADH plays a crucial role in the formation of these toxic metabolites. Additionally, lactic acidosis may occur due to the effects of methanol and ethylene glycol metabolites.