Diuretics for Hypertension: A Review and Update

This review and update focuses on the clinical features of hydrochlorothiazide (HCTZ), the thiazide-like agents chlorthalidone (CTDN) and indapamide (INDAP), potassium-sparing ENaC inhibitors and aldosterone receptor antagonists, and loop diuretics. Diuretics are the second most commonly prescribed class of antihypertensive medication, and thiazide-related diuretics have increased at a rate greater than that of antihypertensive medications as a whole. The latest hypertension guidelines have underscored the importance of diuretics for all patients, but particularly for those with salt-sensitive and resistant hypertension. HCTZ is 4.2-6.2 systolic mm Hg less potent than CTDN, angiotensin-converting enzyme inhibitors, beta blockers, and calcium channel blockers by 24-hour measurements and 5.1mm Hg systolic less potent than INDAP by office measurements. For reducing cardiovascular events (CVEs), HCTZ is less effective than enalapril and amlodipine in randomized trials, and, in network analysis of trials, it is less effective than CTDN and HCTZ-amiloride. Combined with thiazide-type diuretics, potassium-sparing agents decrease ventricular ectopy and reduce the risk for sudden cardiac death relative to thiazide-type diuretics used alone. A recent synthesis of 44 trials has shown that the relative potencies in milligrams among spironolactone (SPIR), amiloride, and eplerenone (EPLER) are approximately from 25 to 10 to 100, respectively, which may be important when SPIR is poorly tolerated. SPIR reduces proteinuria beyond that provided by other renin angiotensin aldosterone inhibitors. EPLER also reduces proteinuria and has beneficial effects on endothelial function. While guidelines often do not differentiate among specific diuretics, this review demonstrates that these distinctions are important for managing hypertension.