Cardioselective blockers (e.g., atenolol, bisoprolol) primarily block β 1 receptors in the heart, causing decreased heart rate, cardiac contractility, cardiac workload, and AVN conduction. Atropine has been shown to be spectacularly ineffective in this setting and alternatives such as β agonists, phospho-diesterase inhibitors, insulin-euglycaemia, and pacing have significantly more associated complications than glucagon without improving outcome.Beta blockers are a group of drugs that inhibit the sympathetic activation of β-adrenergic receptors. However, at an initial dose of 5–10 mg (100 μg/kg) intravenously at £19.95/mg, the cost 4 compares favourably with thrombolysis as a potential lifesaving intervention. It is true that large doses may be required and that this may outstrip hospital supplies. The authors state that glucagon is expensive. Glucagon, however, has been shown to be effective in treating symptomatic β blocker overdose in various controlled animal studies.Ībout 20 deaths per year in the UK are attributed to β blocker overdose.

This is true of most “antidotes” because of ethical constraints on toxicology studies. 2, 3 The evidence for glucagon in treating symptomatic β blocker overdose will probably never reach a higher level than case reports. However, had the search strategy included individual drug names (for example, propranolol, atenolol) more relevant papers would have been found, including two cases of pure β blocker overdose successfully treated with glucagon alone.

1 As the authors recognised, the six studies tabulated were of mixed overdose or had multiple therapeutic interventions and could not answer the question posed. I was interested to read the best BET “Glucagon for the treatment of symptomatic β blocker overdose” by Boyd and Ghosh.

Antidote for beta blocker overdose