Figure 78

Mechanisms of action of diuretics. This figure depicts the major sites and mechanisms of action of diuretic drugs [8]. The diuretic/natriuretic action of benzothiadiazide-type diuretics is predicated on their gaining access to the luminal side of the distal convoluted tubule and inhibiting Na+ - Cl- cotransport by competing for the chloride site.

The diuretic/natriuretic action of loop diuretics is predicated on their gaining access to the luminal side of the thick ascending limb of the loop of Henle and inhibiting Na+ - K+ -2Cl- electroneutral cotransport by competing for the chloride site.

The diuretic/natriuretic action of potassium-sparing diuretics is predicated on their gaining access to the luminal side of the principal cells located in the late distal tubule and cortical collecting duct and blocking luminal sodium channels. Because Na+ uptake is blocked, the lumen negative voltage is reduced, inhibiting K+ secretion. The potassium-sparing diuretic spironolactone does this indirectly by competing with aldosterone for its cytosolic receptor. CA—carbonic anhydrase; CAI—carbonic anhydrase inhibitor; CD—collecting duct; DCT—distal convoluted tubule; DT—distal tubule; LH—loop of Henle; PC—principal cell; PT—proximal tubule; TAL—thick ascending limb. (From Ellison [8]; with permission.)

Side effects

Mechanisms

Thiazide-type diuretic

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