Acute chlormethiazole poisoning in patients notified to the Poisons Unit, Guy's Hospital, 1978--1981.

1 Out of 493 patients with suspected acute chlormethiazole poisoning notified to the Poisons Unit, Guy's Hospital during 1978--1981, the diagnosis was confirmed either analytically or by detailed clinical information in 108 patients, 40 of whom had ingested chlormethiazole alone. 2 The principal signs reported indicate that the clinical features of acute chlormethiazole poisoning resemble those of barbiturate poisoning, with deep coma (n = 66), respiratory depression (n = 26) and hypotension (n = 17) in the severe cases. Five patients died as a result of early, profound respiratory depression. 3 In 53 survivors in whom toxicological analyses were performed, poisoning with chlormethiazole alone had a better prognosis than when ethanol or other drugs were also present, except in patients with hepatic or pulmonary disease or in the elderly. 4 These results emphasise that although patients poisoned with chlormethiazole who survive to reach hospital generally have a good prognosis, fatal respiratory complications often occur before the patient can be treated.