Bromide salts were introduced as hypnoto-sedatives in 1850 and a few years later for the treatment of convulsive seizures. Despite the introduction of barbiturates and other drugs such as phenytoin, bromides are still used in a few patients. A therapeutic range of 10-25 mmol/L in serum is cited, but some patients show signs of toxicity with serum concentrations as low as 5 mmol/L. At concentrations in excess of 35 mmol/L action should be taken to prevent further increase. Bromide in serum is likely to cause a positive interference in methods for the determination of chloride.
With the steep decline in the use of bromide containing preparations, toxicity is now rarely seen, but may result in neurological and dermatological symptoms. Patients usually develop a lethargy but may present with delirium, delusions or hallucinations. The condition may progress to sedation and coma. Other symptoms which may be seen include tremor, dysarthria, ataxia and abnormal eye movements. Some patients may have a profound cachexia while others can have skin rashes and gastrointestinal disorders.
Laboratory Indices of Exposure
Serum bromide measurements are often used to indicate exposure to alkyl bromides, in particular the fumigant methyl bromide. These compounds present a greater hazard than inorganic bromides, and for methyl bromide, serum bromide, levels greater than 0.5 mmol/L (40 mg/L) indicate significant exposure.
Bowers GN, Onoroski M. Hyperchloremia and the incidence of bromism in 1990. Clin Chem 1990; 36: 1399-1403