Carbamazepine and the lung.

A 69 yr old man was admitted with a 10 day history of fever, arthromyalgia, dyspnoea, dry cough and pleuritic pain. Temperature was 38 degrees C; tachypnoea 36 rpm. Extensive crackles were audible over both upper lung fields. Chest X-ray showed bilateral alveolar infiltrates. Forced vital capacity was 49% of predicted, and carbon monoxide transfer coefficient was 32% of predicted value. The patient had been taking carbamazepine for one month because of a trigeminal neuralgia. After withdrawal of the drug he gradually recovered.