[Biochemical evaluation of digoxin dosage in patients with heart failure]

The investigations were carried out in 56 patients aged 54 to 84 years, treated with a supporting dosage 0.25 mg of digoxin because of chronical insufficiency of the heart, according to the NYHA classification II and III degree, in whom the functions of liver and kidneys have not been ascertained. A fourfold determination of digoxin concentrations in the blood was established in the time of distribution balance. From among the examined patients three groups were separated: receiving the drug chronically at 8.00 a.m. (group A), receiving it at 8.00 p.m. (group B) and group C, for which the sacral method was used. Depending on medical indications the patients received during the examination other drugs. In group C the therapy was limited to diuretic drugs. In no clinical symptoms of digitalism could be observed. Subtherapeutic levels of digoxin (< 0.8 ng/ml) were found in the three groups on an average in 50% of the patients. The high percentage of patients with nontherapeutic concentration in blood serum confirms once more, that treatment with digoxin without checking their concentration in the serum does not give the certainty of suitable dosage. The results of the studies show that the optimalization of digoxin therapy from the point of pharmacological view should be based on a penetrating estimation of the whole of the clinical image, the checking of the image with the help of the concentration determinations of the drug.