Diuretics

 Diuretics are drugs that promote the excretion of water and electrolytes (mainly sodium and chloride) from the body through urine. They are commonly used in hypertension, heart failure, renal disorders, and edema.

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🔷 Main Classes of Diuretics

Class Site of Action Example Drugs Mechanism Clinical Use

Loop diuretics Loop of Henle Furosemide, Bumetanide, Torsemide Inhibit Na⁺/K⁺/2Cl⁻ co-transporter Acute pulmonary edema, CHF, hypertension

Thiazide diuretics Distal convoluted tubule Hydrochlorothiazide, Chlorthalidone Inhibit Na⁺/Cl⁻ symporter Hypertension, mild edema

Potassium-sparing diuretics Collecting duct Spironolactone, Amiloride, Eplerenone Inhibit Na⁺ channels or aldosterone receptors Heart failure, hypokalemia prevention

Carbonic anhydrase inhibitors Proximal tubule Acetazolamide Inhibit carbonic anhydrase enzyme Glaucoma, altitude sickness

Osmotic diuretics Proximal tubule & Loop of Henle Mannitol Increase osmotic pressure in filtrate Cerebral edema, acute renal failure

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⚠️ Common Side Effects

Electrolyte imbalance (e.g., hypokalemia, hyperkalemia)

Dehydration

Hypotension

Hyperuricemia (can cause gout)

Gynecomastia (with spironolactone)

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💊 Key Points to Remember

Loop diuretics are the most potent.

Thiazides are first-line for hypertension.

Potassium-sparing diuretics can cause hyperkalemia.

Monitor elec

trolytes and renal function during therapy.