Diuretics

• Diuretics reduce the reabsorption of sodium and water by the renal tubules and consequently increase urinary flow - they are indicated for diseases associated with sodium and water overload (e.g., heart failure, renal failure, ascites, hypertension)
• Loop diuretics (e.g., furosemide) are particularly efficacious because they inhibit sodium reabsorption in the thick ascending limb of the Loop of Henle, which normally reabsorbs up to 25% of the sodium, chloride, and water filtered at the glomerulus
• Thiazide diuretics (e.g., bendroflumethiazide) inhibit reabsorption of around 5–10% of the filtered sodium chloride and water at the distal convoluted tubule
• Potassium-sparing diuretics (e.g., spironolactone) inhibit reabsorption of the remaining 2–3% of sodium in exchange for potassium or hydrogen ions in the late distal tubule and early collecting duct
• Osmotic diuretics (e.g., mannitol) are small inert molecules that are not reabsorbed by the renal tubules and act by creating an osmotic drag that reduces water reabsorption
• Carbonic anhydrase inhibitors (e.g., acetazolamide) reduce the release of hydrogen and bicarbonate ions in the proximal tubule, causing a mild natriuresis and metabolic acidosis