Critical Clarification: Polyethylene Glycol vs. Ethylene Glycol
Polyethylene glycol (PEG) is NOT toxic and does NOT require ethanol treatment or any antidote therapy. 1
Essential Distinction
- Polyethylene glycol is a non-toxic polymer commonly used as a laxative (e.g., MiraLAX) and does not require any specific antidote treatment 1
- Ethylene glycol is the highly toxic component of antifreeze that requires aggressive intervention with alcohol dehydrogenase inhibitors and potentially hemodialysis 1
- The treatment protocols for ethylene glycol poisoning (fomepizole, ethanol, or hemodialysis) are NOT indicated for polyethylene glycol exposure 1
If Ethylene Glycol Co-Ingestion is Suspected
Only if there is confirmed or suspected ethylene glycol (not polyethylene glycol) poisoning should the following ethanol dosing be considered:
Ethanol Dosing Regimen for Ethylene Glycol Poisoning
Loading Dose:
- 10 mL/kg of 10% ethanol IV (or 0.8-1.0 g/kg) administered over 30-60 minutes to achieve target blood ethanol concentration of 100-150 mg/dL 2, 3
Maintenance Dose:
- Non-drinkers: 66-154 mg/kg/hour (approximately 1.4 mL/kg/hour of 10% ethanol) 2
- Chronic drinkers: Higher maintenance rates may be required due to enzyme induction 3
During Hemodialysis:
- Increase maintenance rate to 250-350 mg/kg/hour because ethanol is readily dialyzable 2, 4
- Monitor ethanol levels every 2-4 hours during extracorporeal treatment 2
Target Therapeutic Level
- Maintain blood ethanol concentration at 100-150 mg/dL (22 mmol/L) throughout treatment 2, 3
- This concentration provides adequate competitive inhibition of alcohol dehydrogenase to prevent toxic metabolite formation 3
Indications for Hemodialysis When Using Ethanol
Strong recommendations for hemodialysis with ethanol (lower thresholds than with fomepizole): 2
- Ethylene glycol concentration >50 mmol/L (>310 mg/dL) OR osmol gap >50 2
- Anion gap >27 mmol/L 4, 2
- Severe clinical features: coma, seizures, or acute kidney injury (KDIGO stage 2 or 3) 2
Weaker recommendations (consider hemodialysis): 4
- Ethylene glycol concentration 20-50 mmol/L (124-310 mg/dL) OR osmol gap 20-50 4
- Anion gap 23-27 mmol/L 4
Rationale for Lower Thresholds with Ethanol
- The EXTRIP workgroup uses stronger recommendations for hemodialysis when ethanol is the antidote because alcohol dehydrogenase blockade with ethanol is unpredictable compared to fomepizole 2
- Treatment failures occur even with minimal acidosis when ethanol dosing is suboptimal 5
- Ethanol requires intensive monitoring in a high-dependency unit due to CNS depression, dysphoria, and unpredictable pharmacokinetics 2
Duration of Treatment
- Continue ethanol therapy until ethylene glycol concentration <4 mmol/L (25 mg/dL) 2
- Continue until anion gap normalizes to <18 mmol/L and metabolic acidosis resolves 2
Critical Pitfalls
- Fomepizole is strongly preferred over ethanol when available due to predictable pharmacokinetics, ease of administration, and lack of CNS depression 6
- Ethanol should only be used when fomepizole is unavailable 2, 7
- Subtherapeutic ethanol levels lead to continued toxic metabolite formation, so frequent monitoring is essential 5
- Monitor for alcohol withdrawal in patients with alcohol use disorder, especially during hemodialysis 4