UMEM Educational Pearls

Category: Toxicology

Title: Pharmaceutical Additives - Propylene Glycol

Keywords: propylene glycol, lorazepam, phenytoin (PubMed Search)

Posted: 10/4/2012 by Fermin Barrueto, MD (Updated: 6/13/2024)
Click here to contact Fermin Barrueto, MD

Ever have that alcholic who requires lorazapam doses that start to approach 10mg? 20mg? or even higher. The next step is usually a lorazepam infusion and then send them to the ICU. In the ICU,  the patient develops an unexplained anion gap lactic acidosis.

Check a Lactate - lorazepam has 80% propylene glycol (PG). PG is metabolized to lactate which can accumulate when a lorazepam infusion at an elevated dose is running constantly.  Hypotension, bradycardia and even other EKG changes have been reported. Simply discontinue the infusion and assess your acid-base status. 

Other IV meds that contain PG:

lorazepam - 80% PG

Phenytoin - 40% PG

Phenobarbital - 67.8%

Diazepam - 40% PG