• Although numerous utilization reviews of serum digoxin assays have demonstrated the positive impact of therapeutic drug monitoring, to our knowledge, the question of whether the withdrawal of such a program would reverse the effect has not been addressed. The current study employed a prospective, randomized, crossover design to evaluate this question and document the cost savings. There were 196 serum digoxin assays performed in the 207 patients. It was found that a continuous therapeutic drug—monitoring program was warranted since, after its withdrawal, there was a deterioration in audit criteria performance. Reimplementation of the therapeutic drug—monitoring program resulted in a significant decrease in the average number of assays requested per patient (from 1.41 to 0.73) and an improvement in audit criteria performance.
(Arch Intern Med 1987;147:1405-1408)