Confusion From Pyridostigmine Bromide: Was There Bromide Intoxication?

Abstract

To the Editor.— In the February 23 issue of JAMA , Rothenberg et al 1 described a case of presumed bromism secondary to administration of repeated doses of pyridostigmine bromide. Their conclusion about the relationship between serum bromide and the altered mental status in this case may have other explanations. The following points deserve to be mentioned. First, the rapid resolution of symptoms is inconsistent with the half-life of the bromide ion. The half-life of bromide in serum is 12 days after oral administration. Toxicokinetic calculations, to estimate the bromide concentration 1 day before the actual serum sample was drawn, give a level of no more than 5.5 mmol/L. The single bromide level documented (5 mmol/L) is, as the authors noted, below what might be considered toxic. The therapeutic range for bromide as an antiepileptic drug is 12.5 to 18.8 mmol/L. 2 Levels below 7.5 mmol/L are usually not associated