Acute respiratory failure precipitated by a carbonic anhydrase inhibitor

A 60-year-old white man with chronic bronchitis was noted to develop acute respiratory failure and metabolic acidosis four days after being started on methazolamide (Neptazane) for an ophthalmologic problem. The patient was intubated with ventilator support and improved after his metabolic acidosis resolved. Caution is emphasized in the use of carbonic anhydrase inhibitors in patients with obstructive airway disease.