Clinical Experience with Ouabain Administered in Small Divided Doses in the Monitored Patient

¹ Cardiac Section, Bronx VA Hospital and Mount Sinai School of Medicine, New York

Ouabain was administered intravenously to 117 monitored patients who required digitalization principally for the treatment of atrial arrhythmias with rapid ventricular response and heart failure associated with acute myocardial infarction. The dosage regimen consisted of 0.2 mg initially (or 0.1 mg if the patient had recently received digoxin) followed by 0.1 mg every hour until a therapeutic response had occurred, toxicity developed, or 1 to 1.3 mg ouabain had been administered. Ouabain given according to this schedule allowed the peak effect of previous doses to be observed before further ouabain was given, and theoretically avoided the development of serious toxicity. The therapeutic dose was found to vary widely among individual patients. The mean dose for control of ventricular rate in patients with atrial fibrillation or flutter was 0.79 mg in those not previously on digoxin and 0.73 mg in those on digoxin. The mean dose among patients with acute myocardial infarction who appeared to respond to ouabain was 0.50 mg. Ouabain was effective in 93.5 percent of the patients with atrial arrhythmias and 61.3 percent of those with acute myocardial infarction and failure. Toxicity occurred in 26 percent of the patients but was usually mild and consisted mainly of VPCs. The toxic dose was unpredictable and not significantly different from the therapeutic dose. Because very low doses occasionally caused ventricular irritability, ouabain should be used with caution only in patients who are constantly monitored.