EFFECTIVE use of diuretic drugs requires an understanding of the principles involved in their action. I have found that posing the following questions often will in turn clarify questions and problems raised by physicians consulting me.
1. What is the goal of treating a patient with a diuretic drug?
Clearly, the practical goal is improved health of your patient, but the drug itself cannot guarantee this goal. The drugs included in the term "diuretic"—as the term is ordinarily used today—directly accomplish one thing only, a decrease in the amount of sodium in the body. This decrease in total-body sodium will usually lead to decrease in the amount of water associated with sodium throughout the body and thus in loss of accumulations of extracellular fluids such as edema, ascites, and pleural effusion. The obvious corollary of this statement is that if you do not want to reduce the total body sodium