Prediction of serum concentrations of digoxin in a family practice center

Physicians and clinical pharmacists were compared in their ability to predict serum digoxin concentrations and to discriminate among patients who were subtherapeutic, therapeutic or toxic. Physicians correctly predicted patients having therapeutic serum digoxin concentrations 77 percent of the time, but they were unable to reliably identify subtherapeutic and toxic patients. By incorporating more compliance and pharmacokinetic data into their assessment, pharmacists proved to be more accurate than physicians both in the prediction of serum digoxin concentrations (P less than .01) and in therapeutic classifications (P less than .001). The clinical pharmacist can be a valuable aid to the physician in the prediction and interpretation of serum digoxin concentrations.