[Relationship between digoxin plasma concentrations and frequency of digoxin intoxication (author's transl)].

Using appropriate transformations the relationship between the frequency of digoxin intoxication and the corresponding digoxin plasma levels can be shown to be linear. Therefore the relative frequencies have to be transformed into probits and the digoxin plasma levels have to be replaced by their logarithms. With intoxication frequencies from published data the IC50, i.e., the plasma level leading to an intoxication in 50% of cases, is 2.9 ng/ml. At 1.0 ng/ml the intoxication frequency is estimated below 1%, at 4.0 ng/ml the estimated frequency is just below 80%. In the intoxication diagnosis of a single patient the plasma level is of only poor significance.