[Clinical importance of determining the digoxin level in the serum in long-term beta-methyldigoxin treatment].

The digoxin level was determined by radioimmunologic method in 54 patients with cardiac failure on constant maintaining glycoside treatment with beta-methyldigoxin in doses of 0.7-0.1, 4 mg weekly. The results showed that: Between the maintaining dose of Beta-Methyldigoxin and the serum digoxin level there is not always parallelism in cases of achieved cardiac compensation. In spite of that the achievement of cardiac compensation and its maintainance in more than 85% of the cases is possible with a mean dose of Lanitop 1.0 mg weekly and digoxin serum level between 1.0 and 2.0 ng/ml. Between the toxic manifestations observed and the doses applied there is not a strong correlation. But the high digoxin levels are always potentially toxic.