Propylene glycol used in intravenous drug formulations can reach toxic levels if high doses of the drug formulation are given continuously or if multiple drugs containing propylene glycol is given. This can be a particular problem for a patient in the intensive care unit.
Parameters:
(1) body weight of the patient
(2) drug concentration in mg per mL
(3) propylene glycol concentration in mg per mL
The maximum recommended daily limit for intravenous propylene glycol is 1 gram per kg body weight per day.
maximum exposure to propylene glycol per day in mg =
= 1 * (body weight in kilograms) * 1000
maximum volume of drug that the patient should be exposed to =
= (maximum daily exposure in mg) / (propylene glycol concentration in drug in mg/mL)
maximum daily dose of drug in mg =
= (drug concentration in formulation) * (maximum volume based on propylene glycol)
Conditions associated with propylene glycol accumulation:
(1) kidney disease
(2) recent ethanol ingestion
(3) child < 4 years of age
(4) pregnant woman
(5) liver disease
(6) concurrent therapy with disulfiram or metronidazole
where:
• Conditions 3 to 6 are associated with impaired alcohol dehydrogenase enzyme systems.
When using a drug containing propylene glycol in a patient with one of the above conditions the options include:
(1) reduce the daily dose by 50%
(2) monitor serum levels of propylene glycol (toxic is > 25 mg/dL).
Hemodialysis is effectve in removing high concentrations of propylene glycol.
