A new assay is described for measuring, in patients with congestive heart failure, the therapeutic efficacy of diuretics such as polythiazide, which was shown to have a longer duration of action than hydrochlorothiazide. In terms of weight loss over 1-week periods of therapy with maximal doses of diuretics, there was no significant difference in the activity of hydrochlorothiazide and polythiazide. A prolonged effect on renal sodium excretion, therefore, is not necessarily associated with an improvement in net therapeutic efficacy when these drugs are used in the management of fluid retention secondary to congestive heart failure.
Hutcheon DE, Leonard GB. Therapeutic Efficacy of Diuretics with Different Durations of Action. JAMA. 1963;185(8):640-642. doi:10.1001/jama.1963.03060080036010