Name: Chlorthalidone (Hygroton)
Class: Diuretic (Thiazide)
Mechanism: Inhib. Na+ & Cl- transport in the cortical thick ascending limb and the early distal tubule ® NaCl and water excretion & ¯ excretion of Ca2+ and uric acid.
Absorption: Oral ® good absorption. Takes effect in 1 hr.
Dist.: Metabolism.: Excretion, t½: Long duration of action.
Toxicity/S.E.s: Hypokalemia, hyponatremia, hyperuricemia, weakness, hypercalcemia, Metabolismolic alkalosis, postural hypotension, hypercholesterolemia, hypertriglyceridemia, hyperglycemia (in patients w/DM), and rare hypersensitivity rxns. C/i—pts susceptible to problems with hypokalemia (cirrhosis, pts on digitalis), hyperuricemia (gout), or hypercalcemia. Adverse rxns w/digitalis, lithium. Altered doses of anti-diabetic agents required. Long-term NSAID use may decrease anti-HTN effects.
Utility: Treat hypertension, CHF, nephrotic synd., other Na+-retaining states. Reduce Ca2+ excretion (e.g., prevention of kidney stones).
Special Features: Most commonly prescribed class of diuretics. Most frequently used class of anti-HTN agents. Milder diuretic action than loop diuretics.Rel. ineffective in renal insuff.