Studies in Serum Digoxin

Using a standardized assay technique, serum digoxin has been estimated in a number of elderly patients. The precision possible with this technique is acceptable with higher, potentially toxic serumdigoxin levels but less so at lower levels. Standard conditions were virtually impossible to obtain in view of the many pathological and biochemical abnormalities so often present in the elderly A series of simple measurements was made to determine: the variation of serum digoxin between individuals receiving the same dose of oral digoxin, and in the same individuals at different times and the toxic and non-toxic ranges of serum digoxin. The overlap between toxic and non-toxic ranges was found to be considerably greater than previously reported in younger patients. A simple formula is suggested for the determination of the overall state of digitalisation in a given patient. It is concluded that for elderly patients in clinical situations, the estimation of serum digoxin is of definite value, but less certainly so than for younger subjects.