Tuesday October 10, 2006
Propylene glycol and Ativan drip

Propylene glycol, also known as 1,2-propanediol, is a tasteless, odorless, and colorless liquid that is use for many drugs with poor aqueous solubility including lorazepoam, diazepam, esmolol, nitroglycerin, pentobarbital, phenytoin, bactrim and others. Usually it is safe but important to know that it is metabolized into lactic acid and pyruvate.

Being an intensivist it is imperative to understand the dangers of propylene glycol particularly with Lorazepam drip - particularly if it is continued beyond 48 hours and dose more than 10 mg/hr. Each 2 mg of lorazepam (one ml) on average contains 0.8 ml of propylene glycol. Any unexplained high anion gap metabolic acidosis with elevated osmol gap, should prompt the diagnosis of propylene gylcol toxicity.

Propylene glycol toxicity secondary to high-dose lorazepam infusion should be kept in mind with compromised renal function but may happen with normal kidney. Although propylene glycol toxicity often resolves after discontinuation of Ativan but if acidosis continues, hemodialysis said to lowers propylene glycol serum concentrations.