Abstract
We measured the concentration of digoxin in sera of 136 patients by a radioimmunoassay during maintenance digoxin therapy. The serum digoxin concentration in patients with 0.25mg of tablet was compared with that with 0.25mg of powder produced by the same manufacturer to study the effect of digoxin form on serum digoxin concentration. Mean serum digoxin concentration in patients with 0.25mg of tablet per day was 1.34ng/ml, while in patients with 0.25mg of powder per day was 2.11ng/ml. Mean serum concentration was 1.23ng/ml in both preparations, if toxic patients were omitted. Mean serum digoxin concentration in 8 patients with a definite digoxin intoxication was 3.16ng/ml. Mean serum digoxin concentration in patients with 30mg/100ml or more of BUN was significantly higher than those with 20mg/100ml or less of BUN (p<0.001), but there was no significant difference in serum digoxin concentration between patients with and without high creatinine level. There was a significant negative correlation between the creatinine clearance and serum digoxin concentration. Mean serum digoxin concentration was significantly higher in patients with both digoxin and furosemide than those with digoxin only (p<0.01), and in patients with digoxin, furosemide, and spironolactone than in those with only digoxin (p<0.001). Serum digoxin concentration was elevated with advance of cardiac failure. There was no significant difference between the elderly (60 years or more) and the adult (less than 60 years old) groups in mean serum digoxin concentration. There was no difference between the 2 groups in prevalence of digoxin intoxication.
