[Serum glycoside level in old age. Problems of course control in glycoside therapy]

Many intoxications--up to 20%--and the often described "digitalis-incompatibility of old age" require a strict indication for this long term therapy and a critical discussion to conceptions like "old age-heart" and "insufficiency of old age-heart". The factors of uncertainty for efficient therapy -- unknown rates of resorption and elimination, mistakes in dosage by patients and interaction with other medicaments on account of the multimorbidity of old age -- demand a better control than only clinical observation and electrocardiography. In 25 patients the serum glycoside concentration was evaluated during several weeks at constant dose by radioimmunoassay and analyzed. Digoxin-assay has to be available as an "emergency-measure", since the early diagnosis of digitalis intoxication in old patients is often very difficult because of the ambiguous clinical picture. 63 patients of different age with normal function of the kidneys (endogenous creatinin-clearance, nephrography with iodine-131-hippuran) were treated with 0,75 mg digoxin/die orally and the serum glycoside concentration was evaluated after 8, 24 and 48 hours by radioimmunoassay; we only found a dependence on weight, but not on the age of our patients. In old age, digoxin is metabolized in the same way as in young age, but because of frequent kidney diseases, kidney function should be assessed carefully before long term digoxin therapy.