The physical characteristics and applications of propylene glycol and ethylene glycol are comparable. Only one methyl group (HOCH2CH2OH in the case of ethylene glycol and CH3CH[OH]CH2OH in the case of propylene glycol) separates their chemical structures. Humans are susceptible to acute poisoning from ethylene glycol. Contrarily, propylene glycol is a food and pharmaceutical component that is "generally recognized as safe". The use of propylene glycol as a diluent for the intravenous administration of benzodiazepines has been responsible for the majority of recorded cases of propylene glycol poisoning.
The Food and Drug Administration (FDA) typically recognizes propylene glycol as safe for use in food and tobacco products, medications, and cosmetics. Other useful applications for it include plasticizers, heat transfer and hydraulic fluids, deicers, coolants, antifreeze, smoke screens, smoke simulators, and other things.
Propylene glycol exposure in the general population is mostly a result of skin contact with cosmetics or topical treatments, as well as consumption of food and pharmaceuticals. Pharmaceuticals, cosmetics, and oral, injectable, and topical formulations all employ propylene glycol as a solvent.Many intravenous and oral medications, such as phenytoin, diazepam, and lorazepam, contain propylene glycol as a diluent. Normal usage of these items is unlikely to have any negative consequences for your health. The body now contains excessive amounts of propylene glycol due to the widespread use of injectable drugs that contain it. Excess propylene glycol levels have also been brought on by prolonged and extensive topical treatment of damaged skin, such as burns.
Patients in intensive care, for example, might experience toxicity from either of the following:
Excessively large or rapidly infused intravenous injections of propylene glycol-containing medications.
Prolonged dermal contact during treatment of burns.
Patients at risk for propylene glycol toxicity include the following:
Patients with underlying kidney disease
Patients with less effective or impaired alcohol dehydrogenase enzyme systems (e.g., children younger than 4 years, pregnant women, patients with hepatic disease, and patients treated with disulfiram or metronidazole)
Patients with epilepsy
Burn patients who receive extensive dermal applications of propylene glycol
Because this illness is iatrogenic, the best course of action may be to reduce the amount of propylene glycol administered to patients in the critical care unit. For individuals with underlying risk concerns, healthcare professionals should take a 50% reduction in the maximum daily dose into consideration. It is possible to calculate from the adult data the maximum daily dose of medication for a young patient.It is possible to treat metabolic acidosis brought on by high levels of propylene glycol in injectable drugs by stopping the offending drug and administering sodium bicarbonate and fomepizole. Hemodialysis can effectively reduce blood propylene glycol levels in situations of extreme hyperosmolality.