In this prospective randomised study 12 patients suffering from
cirrhosis of the liver (stable phase) and 12 healthy male volunteers were treated with either 0.3 mg
beta-methyldigoxin (
Lanitop) or 0.4 mg
beta-acetyldigoxin (
Novodigal) daily, orally. Every day the total serum
digoxin concentrations of the patients and volunteers were measured by radioimmunoassay. Both
digoxin and
beta-methyldigoxin are measured by this method. In subjects receiving
beta-methyldigoxin therapy the ratio of
beta-methyldigoxin to
digoxin in the serum was determined by liquid chromatography. The
digoxin levels in patients with
cirrhosis treated with
beta-methyldigoxin were statistically significantly higher than in healthy volunteers. In patients with
cirrhosis the proportion of serum
beta-methyldigoxin averaged 77.7% of the total
digoxin concentration, whereas the proportion was only 37.5% in healthy volunteers. With
beta-acetyldigoxin there was no statistically significant difference between patients with
cirrhosis and healthy volunteers. Alterations in pharmacokinetics may cause the higher total serum
digoxin concentrations in cirrhotic patients. The following factors seem to be important: longer elimination half life, changes in distribution volume and reduced renal clearance. There is greater danger of digitalis toxicity in patients with
cirrhosis of the liver on standard dosage of
beta-methyldigoxin than on standard dosage of
beta-acetyldigoxin.