We report a case of hypotension and bradycardia associated with intravenous fomepizole infusion.
Case report: A 59-year-old man presented to hospital 10 hours after ethylene glycol ingestion with ataxia, slurred speech, metabolic acidosis, heart rate 70/min, blood pressure 160/100 mmHg. Treatment with hemodialysis and fomepizole began 7.5 hours after admission. Severe bradycardia (29/min) and hypotension (69 mmHg systolic) occurred immediately following a 30 minute intravenous infusion of the first (19 mg/kg) fomepizole dose, but rapidly corrected with 1 mg atropine. Transient bradycardia (48/min) and hypotension (89/57 mmHg) recurred immediately after the second (10 mg/kg) fomepizole dose, also given during dialysis.
Discussion: Hemodialysis may cause a drop in blood pressure and heart rate; however, the close temporal relationship with fomepizole infusions, dose-related symptom intensity and recurrence with rechallenge suggest a causal relationship with fomepizole. Hemodialysis, acidosis and high initial fomepizole dose may have enhanced patient susceptibility, as a post-dialysis fomepizole dose was well tolerated.
Conclusion: Fomepizole may precipitate bradycardia and/or hypotension during hemodialysis. Monitor vital signs closely during and immediately after infusion.