The following parenteral (or intravenous; IV) medications are known to contain propylene glycol as a diluent:

• Diazepam (Valium) 
• Lorazepam (Ativan)
• Phenobarbital
  
• Phenytoin (Dilantin)
• Nitroglycerin

• Seizures:
• When using phenytoin (Dilantin) or fosphenytoin (Cerebyx) it is important to know that there is a difference between impacts rate of infusion and side effects.
• When these are being administered parenterally as IV push, phenytoin can only be given at a max rate of 50 mg/min due to the presence of propylene glycol (PG) whereas fosphenytoin can be given at 150 mg /min because it does not contain PG. 
• Giving phenytoin too fast can cause hypotension and bradydysrhythmias because of the presence of propylene glycol.
• ICU Sedation: 
• It appears that patients who get long IV infusions of benzodiazepines are at greater risk for PG associated anion gap, metabolic acidosis.

• Toxicology:  Ethylene Glycol - Overview
• Toxicology:  Isopropanol - Overview
  
• Toxicology:  Methanol - Overview
• Calculator:   Anion Gap
  

1. Wilson KC et al. Propylene glycol toxicity: a severe iatrogenic illness in ICU patients receiving IV benzodiazepines: a case series and prospective, observational pilot study. Chest 2005;128(3):1674-81.  PubMed
   
2. Horinek EL et al. Propylene glycol accumulation in critically ill patients receiving continuous intravenous lorazepam infusions. Ann Pharmacother 2009;43(12):1964-71.  PubMed
   
3. Pillai U et al. Severe propylene glycol toxicity secondary to use of anti-epileptics. Am J Ther 2014;21(4):e-106-9.  PubMed
   
4. Bledsoe KA et al. Propylene glycol toxicity complicating use of barbiturate coma. Neurocrit Care 2008;9(1):122-4.  PubMed
   
5. Demey HE et al.  Propylene glycol-induced side effects during itravenous nitroglycerin therapy. Intensive Care Med 1988;14(3):221-6.  PubMed