Digoxin concentration in cerebrospinal fluid-a study carried out after 9 days of treatment of beta-methyldigoxin or beta-acetyldigoxin.

Two groups of seven healthy volunteers were treated for 9 days with either 0.3 mg beta-methyldigoxin or 0.4 mg beta-acetyldigoxin daily, applied orally. On the 10th day, digoxin concentrations in plasma and cerebrospinal fluid (CSF) were determined by radioimmunoassay. After therapy with beta-methyldigoxin the plasma/CSF digoxin concentration ratio was 3.7:1; after therapy with beta-acetyldigoxin it was 3.2:1. There was no significant difference in the plasma/CSF digoxin concentration ratio after 9 days of treatment with equipotent doses of beta-methyldigoxin and beta-acetyldigoxin.