There are now a number of different classes of diuretics with different pharmacologic effects. Several considerations dictate the choice of diuretic: 1. The responsiveness of the patient is of prime importance. If the patient is not known to be resistant to diuretic therapy, thiazides should be tried first. 2. The danger of alterations of volume and of electrolytes in the specific patient must be considered. Patients receiving digitalis will be subjected to much greater danger by the induction of hypokalemia than patients not receiving cardiac glycosides. 3. The pharmacologic effects of the specific diuretics must be understood for now the physician has available agents of differing potency, efficacy, and especially differing mechanisms of action
