Seizure activity and anion gap metabolic acidosis secondary to adverse effect of nalidixic acid—a case report

Nalidixic acid is a commonly prescribed treatment for suspected dysentery in Middle Eastern populations. We describe a case of convulsions resulting from a single dose of nalidixic acid in a previously healthy two-month-old child in Northern Iraq who was being treated for a diarrhoeal illness. The child presented to us with new onset seizures, irritability, and acidaemia. Nalidixic acid was thought to be responsible after the exclusion of other potential causes of seizures. Symptoms resolved by treatment with intravenous (IV) diazepam, and cessation of nalidixic acid, and the child recovered fully and was discharged home neurologically intact after two days of observation. In regions where it is commonly prescribed, such as Northern Iraq, nalidixic acid should be considered as a cause of convulsions in any seizing child who has been exposed to the drug. Furthermore, quinolones such as nalidixic acid are contraindicated in children < 3 months of age.