title: Successful treatment of a massive metoprolol overdose using intravenous lipid emulsion and hyperinsulinemia/euglycemia therapy.
abstract: Adrenergic β-antagonists, commonly known as β-blockers, are prescribed for many indications including hypertension, heart failure, arrhythmias, and migraines. Metoprolol is a moderately lipophilic β-blocker that in overdose causes direct myocardial depression leading to bradycardia, hypotension, and the potential for cardiovascular collapse. We describe the case of a 59-year-old man who intentionally ingested ~7.5 g of metoprolol tartrate. Initial treatment of bradycardia and hypotension included glucagon, atropine, dopamine, and norepinephrine. Despite these treatment modalities, the patient developed cardiac arrest. Intravenous lipid emulsion (ILE) and hyperinsulinemia/euglycemia (HIE) therapies were initiated during advanced cardiac life support and were immediately followed by return of spontaneous circulation. Further treatment included gastric lavage, activated charcoal, continued vasopressor therapy, and a repeat bolus of ILE. The patient was weaned off vasoactive infusions and was extubated within 24 hours. HIE therapy was continued for 36 hours after metoprolol ingestion. A urine β-blocker panel using mass spectrometry revealed a metoprolol concentration of 120 ng/ml and the absence of other β-blocking agents. To date, no clear treatment guidelines are available for β-blocker overdose, and the response to toxic concentrations is highly variable. In this case of a life-threatening single-agent metoprolol overdose, the patient was successfully treated with HIE and ILE therapy. Due to the increasing frequency with which ILE and HIE are being used for the treatment of β-blocker overdose, clinicians should be aware of their dosing strategies and indications.
authors.affiliation: Department of Pharmacy, Oregon Health & Science University, Portland, Oregon.
authors.forename: Cassie A
authors.initials: CA
authors.lastname: Barton
authors.affiliation: Department of Pharmacy, Oregon Health & Science University, Portland, Oregon.
authors.forename: Nathan B
authors.initials: NB
authors.lastname: Johnson
authors.affiliation: Department of Pharmacy, Oregon Health & Science University, Portland, Oregon.
authors.forename: Nathan D
authors.initials: ND
authors.lastname: Mah
authors.affiliation: Department Emergency Medicine, Oregon Health & Science University, Portland, Oregon.
authors.forename: Gillian
authors.initials: G
authors.lastname: Beauchamp
authors.affiliation: Department Emergency Medicine, Oregon Health & Science University, Portland, Oregon.
authors.forename: Robert
authors.initials: R
authors.lastname: Hendrickson
mesh_terms: D058671:Adrenergic beta-1 Receptor Antagonists / Q000506:poisoning*; D062787:Drug Overdose / Q000150:complications / Q000628:therapy*; D005217:Fat Emulsions, Intravenous / Q000627:therapeutic use*; D006323:Heart Arrest / Q000139:chemically induced / Q000628:therapy; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007328:Insulin / Q000627:therapeutic use*; D008297:Male; D008790:Metoprolol / Q000506:poisoning*; D008875:Middle Aged
chemical_list: D058671:Adrenergic beta-1 Receptor Antagonists; D005217:Fat Emulsions, Intravenous; D007004:Hypoglycemic Agents; D007328:Insulin; D008790:Metoprolol
keywords: insulin; lipid emulsion; metoprolol; overdose; β-adrenergic agent