From the Guidelines
Ethylene glycol poisoning is a medical emergency requiring immediate treatment with fomepizole or ethanol, along with hemodialysis in severe cases, as recommended by the EXTRIP workgroup 1. The initial dose of fomepizole is 15 mg/kg IV, followed by 10 mg/kg every 12 hours for 4 doses, then 15 mg/kg every 12 hours until ethylene glycol levels are below 20 mg/dL. If fomepizole is unavailable, ethanol can be administered as a 10% IV solution with a loading dose of 10 mL/kg, followed by 1-2 mL/kg/hour, maintaining blood ethanol levels at 100-150 mg/dL.
Key Considerations
- The EXTRIP workgroup suggests ECTR if fomepizole is used and EG concentration > 50 mmol/L OR osmol gap > 50 1.
- The workgroup recommends ECTR if ethanol is used and EG concentration > 50 mmol/L OR osmol gap > 50 1.
- ECTR is also recommended if glycolate concentration is > 12 mmol/L or anion gap > 27 mmol/L 1.
- In patients presenting with EG poisoning requiring ECTR, intermittent hemodialysis is recommended over other types of ECTR, with continuous kidney replacement therapy (CKRT) as an alternative if hemodialysis is not available 1.
Supportive Care
- Correcting metabolic acidosis with sodium bicarbonate
- Maintaining electrolyte balance
- Providing thiamine and pyridoxine to help metabolize toxic intermediates
Rationale
The treatment of ethylene glycol poisoning works by blocking the enzyme alcohol dehydrogenase, preventing the formation of toxic metabolites while the parent compound is eliminated 1. Early recognition of symptoms like inebriation, nausea, vomiting, and altered mental status, along with prompt treatment, significantly improves outcomes and prevents permanent organ damage.
Important Considerations
- The decision to initiate ECTR should be individualized, taking into account the patient's clinical condition, the availability of antidotes, and the potential risks and benefits of treatment 1.
- The EXTRIP workgroup acknowledges that the quality of evidence for these recommendations is very low, and therefore, these decisions should be made on a case-by-case basis 1.
From the FDA Drug Label
Treatment Guidelines If ethylene glycol or methanol poisoning is left untreated, the natural progression of the poisoning leads to accumulation of toxic metabolites, including glycolic and oxalic acids (ethylene glycol intoxication) and formic acid (methanol intoxication) Treatment consists of blocking the formation of toxic metabolites using inhibitors of alcohol dehydrogenase, such as fomepizole injection, and correction of metabolic abnormalities Begin fomepizole injection treatment immediately upon suspicion of ethylene glycol or methanol ingestion based on patient history and/or anion gap metabolic acidosis, increased osmolar gap, visual disturbances, or oxalate crystals in the urine, OR a documented serum ethylene glycol or methanol concentration greater than 20 mg/dL Hemodialysis should be considered in addition to fomepizole injection in the case of renal failure, significant or worsening metabolic acidosis, or a measured ethylene glycol or methanol concentration of greater than or equal to 50 mg/dL.
Ethylene Glycol Poisoning Treatment:
- The treatment for ethylene glycol poisoning involves administering fomepizole injection to block the formation of toxic metabolites.
- Fomepizole injection should be started immediately if there is suspicion of ethylene glycol ingestion, based on patient history, anion gap metabolic acidosis, or a documented serum ethylene glycol concentration greater than 20 mg/dL.
- Key Considerations:
- Hemodialysis should be considered in cases of renal failure, significant metabolic acidosis, or ethylene glycol concentrations greater than or equal to 50 mg/dL.
- Fomepizole injection dosing should be adjusted during hemodialysis, with doses administered every 4 hours.
- Treatment should continue until ethylene glycol concentrations are undetectable or reduced below 20 mg/dL, and the patient is asymptomatic with normal pH 2.
From the Research
Ethanol Glycol Poisoning Treatment
- Fomepizole is used to treat and prevent toxicity from ethylene glycol poisoning 3, 4, 5, 6, 7
- Treatment with fomepizole without hemodialysis in massive ethylene glycol ingestion has been reported in the literature 3, 5
- Fomepizole inhibits the enzyme alcohol dehydrogenase (ADH), which prevents the formation of toxic metabolites 4, 6, 7
- The use of fomepizole as an antidote has several advantages, including ease of administration, no need to monitor concentrations, and a lower occurrence of side-effects compared to ethanol 4, 7
Indications for Hemodialysis
- Hemodialysis is considered a key element in the treatment of severe ethylene glycol and methanol intoxication 4
- Published literature and practice guidelines suggest considering hemodialysis initiation in patients with an ethylene glycol level > 50 mg/dL 3
- However, treatment with fomepizole without hemodialysis may be a viable alternative option in patients with even extremely high plasma ethylene glycol concentrations, as long as their renal function is intact 3, 5
Efficacy and Safety of Fomepizole
- Fomepizole has been shown to be effective in preventing renal injury and metabolic acidosis in patients with ethylene glycol poisoning 6
- The plasma concentration of glycolate and the urinary excretion of oxalate, the major metabolites of ethylene glycol, uniformly fell after the initiation of fomepizole therapy 6
- Fomepizole is generally well-tolerated, with few adverse effects reported 6, 7