[Isoniazid intoxication].

HISTORY AND ADMISSION FINDINGS: A 55-year-old woman presented with sustained convulsions after the ingestion of an at first unknown amount of isoniazid, rifampin, ethambutol and alcohol.

INVESTIGATION: At admission the patient had a severe metabolic acidosis. Blood tests showed changes caused by the hepatotoxicity of isoniazid.

TREATMENT AND COURSE: Because diazepam was not efficacious in controlling the convulsions the patient was intubated. In response to the therapautic measures the convulsions stopped and metabolic acidosis was quickly compensated. Pyridoxine was given intravenously as an antidote.

CONCLUSION: The rare intoxication with isoniazid demands immediate administration of pyridoxine and aggressive treatment of the convulsions.