Q: Depending on Lorazepam infusion rate, what could be one way of suspecting Propylene Glycol (PG) toxicity?

Answer:  Though formulations of lorazepam infusion containing PG vary based on product and manufacturer, but in general mixing 1 mg of lorazepam with 1 ml of diluent yields a final solution containing 0.4 ml (415 mg) of PG for each milliliter of infusion. Serum levels of 17.7 mg/dl are associated with increased serum lactate and elevated anion gap acidosis.