[An 88-year-old woman with symptoms of intoxication due to a small dose of digoxin].

An 88-year-old woman was admitted to our hospital because of palpitations, dyspnea, orthopnea and appetite loss. On admission, small crackles were heard on her lower back, and her liver was swollen. Chest rentogenogram showed cardiomegaly (cardio-thoracic ratio 65.5%) and bilateral pleural effusion. Electrocardiograms showed atrial fibrillation with an average heart rate of 95 per minute. Echocardiography revealed mitral stenosis. Because the patient was considered to be suffered from heart failure due to mitral stenosis with atrial fibrillation, furosemide (20 mg per day) and digoxin (0.25 mg per day) was started. After digoxin had been raised to a dose of 0.50 mg per day because of sustained rapid ventricular response on the fourth hospital day, she complained of nausea and vomiting. Serum digoxin concentration was 2.55 ng/ml on the next day, and 1.08 ng/ml 96 hours after discontinuing digoxin. There was no complaint after digoxin was restarted with a dose of 0.05 mg per day. She complained of nausea again on the third day when the digoxin was raised to a dose of 0.083 mg in a blinded study. This observation indicates that digoxin intoxication could occur even in the smaller dose of digoxin than usual in the elderly.