How to manage propylene glycol (PG) cardiac toxicity?

Management of Propylene Glycol Cardiac Toxicity

Propylene glycol cardiac toxicity should be managed with immediate discontinuation of all propylene glycol-containing medications, close cardiac monitoring, and hemodialysis in severe cases with metabolic derangements.

Clinical Presentation and Diagnosis

Propylene glycol (PG) toxicity can present with cardiac manifestations that may mimic sepsis or other critical conditions. Key clinical features include:

• Cardiac manifestations:

  • Bradydysrhythmias
  • Hypotension
  • QRS prolongation
  • Ventricular dysrhythmias
  • Cardiogenic shock in severe cases

• Associated metabolic derangements:

  • High anion gap metabolic acidosis
  • Elevated osmolar gap (>10 mOsm/L)
  • Lactic acidosis
  • Hyperosmolality

Management Algorithm

Step 1: Immediate Interventions

• Discontinue all medications containing propylene glycol 1
• Establish continuous cardiac monitoring
• Obtain baseline laboratory studies:
  • Electrolytes, BUN, creatinine
  • Arterial blood gas
  • Serum osmolality (measured and calculated)
  • Lactic acid level
  • Propylene glycol level (if available)

Step 2: Treat Cardiac Manifestations

• For bradydysrhythmias:

  • Administer atropine for life-threatening bradycardia 2
  • Consider temporary cardiac pacing for refractory bradydysrhythmias 2

• For ventricular dysrhythmias:

  • Consider lidocaine for ventricular dysrhythmias 2
  • Avoid class Ia and Ic antiarrhythmics which may worsen sodium channel blockade

• For hypotension/shock:

  • Administer IV crystalloids
  • Consider vasopressors for refractory hypotension
  • For severe refractory cases, venoarterial extracorporeal membrane oxygenation (VA-ECMO) may be considered 2

Step 3: Correct Metabolic Derangements

• For metabolic acidosis:

  • Administer sodium bicarbonate for severe acidosis (pH < 7.2) 2
  • Monitor serum pH and bicarbonate levels

• For significant toxicity with metabolic derangements:

  • Initiate hemodialysis, which effectively removes propylene glycol 1
  • Indications for hemodialysis:
    • Severe metabolic acidosis refractory to bicarbonate
    • High osmolar gap (>20 mOsm/L)
    • Acute kidney injury
    • Significant cardiac toxicity

High-Risk Populations

Patients at increased risk for propylene glycol toxicity include:

• Those with renal insufficiency 3, 1
• Those with hepatic dysfunction 1
• Patients receiving high doses of PG-containing medications 4
• Patients receiving multiple PG-containing medications concurrently 3

Common Sources of Propylene Glycol

Be vigilant about medications that commonly contain propylene glycol:

• IV benzodiazepines (lorazepam, diazepam) 4
• IV phenobarbital and phenytoin 5
• IV trimethoprim-sulfamethoxazole 3
• Some oral liquid medications
• Some topical preparations

Prevention Strategies

• Calculate total daily propylene glycol exposure when using multiple PG-containing medications
• Consider alternative medications without propylene glycol (e.g., midazolam instead of lorazepam) 4
• Monitor osmolar gap regularly in patients receiving high-dose or multiple PG-containing medications 5
• Reduce doses in patients with renal or hepatic dysfunction
• Monitor renal function in patients receiving PG-containing medications

Monitoring During Treatment

• Continuous cardiac monitoring
• Serial measurements of:
  • Electrolytes and acid-base status
  • Osmolar gap
  • Renal function
  • Lactic acid levels
  • Cardiac biomarkers if cardiac injury is suspected

Early recognition and prompt management of propylene glycol toxicity are essential to prevent progression to severe cardiac complications and improve outcomes.