Digitoxin kinetics in patients with impaired renal function

Abstract

Serum digitoxin levels were recorded during maintenance therapy, absorption‐distribution, and elimination of digitoxin in patients with poor renal function. The analysis was carried out with a modified Rb 86 method and the results were compared with results in subjects with normal renal function. During both absorption and maintenance therapy serum digitoxin levels of the patients with poor renal function were significantly lower than those of the control group. However, most of these differences could be ascribed to different concentrations of serum proteins in the two populations. When this factor was corrected for, most of the differences disappeared and became non‐significant. The elimination of digitoxin was not significantly different in the two groups. The absence of impaired digitoxin elimination during uremia indicates the development of compensatory mechanisms for the elimination of active glycosides. Although the elimination of digitoxin may be normal in uremia, the myocardial sensitivity to the drug may be changed. Digitoxin is probably the glycoside of choice in uremia, since other glycosides are more dependant on renal excretion for elimination.