Makindo Medical Notes

Related Subjects: |Metabolic acidosis |Aspirin or Salicylates toxicity |Ethylene glycol toxicity |Renal Tubular Acidosis |Lactic acidosis

FDA: The use of fomepizole is recommended if ethylene glycol or methanol serum levels are above 20 mg/dl or if ingestion of methanol/ethylene glycol is suspected. In cases where ethylene glycol levels are equal to or above 50 mg/dl, or when the patient has renal failure or worsening metabolic acidosis, haemodialysis should also be considered. Haemodialysis removes fomepizole, therefore doses must be given more frequently during haemodialysis.

About: Always check the BNF link here

• Advice on the treatment of ethylene glycol and methanol poisoning should be obtained from the National Poisons Information Service
• Used to prevent alcohol metabolism to toxic metabolites but very expensive

Mode of action

• 4-methylpyrazole [4-MP] which Inhibits alcohol dehydrogenase

Indications

• Methanol toxicity serum levels are above 20 mg/dl
• Ethlene glycol toxicity serum levels are above 20 mg/dl

Dose: Same for Ethylene Glycol and Methanol

• Loading dose: Fomepizole 15 mg/kg IV infusion over 30 min, THEN 10 mg/kg IV BD for 4 doses, THEN increase to 15 mg/kg BD. Treat until ethylene glycol or methanol levels are <20 mg/dL.
• Add the dose of Fomepizole into at least 100 mL of sterile 0.9% sodium chloride injection or dextrose 5% injection. Mix well. Give over 30 minutes.
• Maintenance dose: 15 mg/kg IV every 12 hours thereafter until levels of ethylene glycol or methanol are reduced below 20 mg/dL, and the patient is asymptomatic with normal pH
• Dialysis may also be required. Loading dose and twice-daily intravenous dosing
• Fomepizole is dialysable and should be given during haemodialysis.

Interactions

• See BNF

Contraindications

• Known allergy

Side effects

• Venous irritation and phlebosclerosis when given undiluted
• Headache, Nausea, Drowsiness, Mild rash and eosinophilia
• Transient elevated transaminases

References