Propylene Glycol, urine

Ethylene Glycol is the main constituent of many antifreeze products. It may be ingested either accidentally or for the purpose of inebriation or suicide. Ethylene glycol itself is relatively non-toxic and its initial CNS effects resemble those of ethanol. The problem arises from the metabolism of ethylene glycol in the liver by alcohol dehydrogenase. This metabolism results in a number of toxic metabolites including oxalic acid and glycolic acid. The clinical effects observed include neurological abnormalities, severe metabolic acidosis, acute renal failure and cardiopulmonary failure. Ethylene glycol has a relatively short half-life of approximately three hours, so early detection is essential to initiate appropriate treatment. 

Propylene Glycol is used extensively as a substitute for ethylene glycol in automotive antifreeze. It has a number of pharmaceutical applications including its use as a preservative, emollient (softener) and a vehicle for both oral and intravenous medications. About half of the Propylene glycol is excreted unchanged by the kidneys. The remainder is oxidized by alcohol dehydrogenase to lactate, pyruvate and acetate. Although Propylene glycol is considered to be relatively non-toxic, there are documented cases of decreased consciousness, seizures and lactic acidosis. 

Diethylene Glycol is a derivative of ethylene glycol. Both compounds when present in the body can result in acute renal failure, matabolic acidosis, CNS depression and respiratory failure. Diethylene glycol does not break down into two ethylene glycol molecules. Instead, the body metabolizes DEG to 2-Hydroxyethoxyacetic Acid (HEAA). Diethylene glycol has occurred as a contaminant or has been used as a substitute for propylene glycol and glycerin in the pharmaceutical industry throughout history. Some of the more famous cases include:

• United States (1937): 105 patients died when diethylene glycol was used as a diluent in the antibiotic preparation Elixir Sulfanilamide
• Haiti (1996): 85 children died due to glycerin contaminated with diethylene glycol in an acetaminophen syrup.
• Bangladesh (1990): 339 children developed kidney failure and many died following ingestion of an acetaminophen syrup contaminated with diethylene glycol
• Panama (2006): 46 deaths investigated by the CDC were linked to a cough medicine prepared from a glycerin product produced in China. It was determined that the glycerin was contaminated with diethylene glycol.