Acute pulmonary edema after a single oral dose of acetazolamide

Anaphylactic shock and pulmonary edema are unusual but life-threatening adverse reactions to drugs. We encountered a case of serious anaphylactic shock and acute pulmonary edema caused by a single oral intake of acetazolamide, a frequently used medication by several medical specialties especially in ophthalmology.

An 80-year-old female was admitted to our emergency Coronary Unit presenting symptoms and signs of shock with acute pulmonary edema. Patient was hospitalised at the Opthalmological Department with intention to undergo cataract surgery. Approximately, four hours before operation, half a tablet of acetazolamide 250 mg was given, in order to control her pre-operative intraocular pressure. Half an hour later, she complained of nausea, became cyanotic, and suffered acute respiratory failure with characteristic massive pulmonary edema. Ventilatory support was initiated and O2 saturation increased to 89%. She was administered 2 ampoules of intravenously furosemide. The blood chemistry panel was normal, as well as myocardial cytolysis tests. Chest radiograph showed enlarged cardiothoracic index, ill-defined vessels, peribronchial cuffing, alveolar edema. An echocardiogram showed normal atria and ventricles, normal systolic function, and excluded pulmonary hypertension. Furosemide (40 mg/IV, S: 1x3) and oxygen (8 Lt/min) were administered for the following 24 hours. Clinical improvement was seen and the O2 saturation was normalized. ECG controls were normal. The patient experienced a full recovery and was discharged 3 days later.

The relationship between anaphylactic shock with acute pulmonary edema and acetazolamide seems highly probable in this case, considering the short time between drug assumption and onset of symptoms (about 30 minutes) and the absence of previous diseases to which symptoms could be related. The patient was not previously treated with acetazolamide. Nowadays, the clinical use of acetazolamide is very limited. Its principal uses are in the preoperative treatment of closed angle glaucoma and continuative therapy of open angle glaucoma.