Types of Diuretics and Their Mechanisms:

1. Thiazide Diuretics:

   • Mechanism of Action: Inhibit the sodium-chloride symporter in the distal convoluted tubule, leading to decreased sodium and water reabsorption.
   • Examples: Hydrochlorothiazide, Chlorthalidone.
   • Indications: Hypertension, heart failure, nephrolithiasis due to idiopathic hypercalciuria.
   • Side Effects: Hypokalemia, hyperglycemia, hyperlipidemia, hyperuricemia, hyponatremia.

2. Loop Diuretics:

   • Mechanism of Action: Inhibit the Na⁺/K⁺/2Cl⁻ cotransporter in the thick ascending limb of the loop of Henle, resulting in significant diuresis.
   • Examples: Furosemide, Bumetanide, Torsemide.
   • Indications: Acute pulmonary edema, chronic heart failure, hypertension, hypercalcemia.
   • Side Effects: Hypokalemia, ototoxicity, dehydration, metabolic alkalosis, hypomagnesemia.

3. Potassium-Sparing Diuretics:

   • Mechanism of Action: Inhibit sodium channels or aldosterone receptors in the distal convoluted tubule and collecting duct, leading to reduced potassium excretion.
   • Examples: Spironolactone (aldosterone antagonist), Amiloride, Triamterene (sodium channel blockers).
   • Indications: Hypertension, heart failure, primary hyperaldosteronism.
   • Side Effects: Hyperkalemia, gynecomastia (spironolactone), menstrual irregularities.

4. Carbonic Anhydrase Inhibitors:

   • Mechanism of Action: Inhibit carbonic anhydrase in the proximal convoluted tubule, leading to decreased bicarbonate reabsorption and increased diuresis.
   • Examples: Acetazolamide.
   • Indications: Glaucoma, altitude sickness, metabolic alkalosis.
   • Side Effects: Metabolic acidosis, hypokalemia, renal stones, paresthesias.

5. Osmotic Diuretics:

   • Mechanism of Action: Increase osmotic pressure in the renal tubules, preventing water reabsorption.
   • Examples: Mannitol.
   • Indications: Cerebral edema, increased intraocular pressure, acute renal failure.
   • Side Effects: Pulmonary edema, dehydration, electrolyte imbalances.

Additional Relevant Information:

Contraindications:

• Severe renal impairment (specific to certain diuretics like thiazides and loop diuretics).
• Anuria (no urine output).
• Electrolyte imbalances (e.g., significant hypokalemia or hyperkalemia).

Drug Interactions:

• Thiazide and Loop Diuretics: Concurrent use with digoxin can increase the risk of digoxin toxicity due to hypokalemia.
• Potassium-Sparing Diuretics: Use with ACE inhibitors or ARBs can increase the risk of hyperkalemia.

Table: Summary of Diuretics

Type	Mechanism of Action	Examples	Indications	Side Effects
Thiazide Diuretics	Inhibit Na⁺/Cl⁻ symporter in DCT	Hydrochlorothiazide	Hypertension, CHF, nephrolithiasis	Hypokalemia, hyperglycemia
Loop Diuretics	Inhibit Na⁺/K⁺/2Cl⁻ cotransporter in loop of Henle	Furosemide	Edema, CHF, hypertension	Hypokalemia, ototoxicity
Potassium-Sparing	Inhibit Na⁺ channels or aldosterone receptors	Spironolactone	Hypertension, CHF, aldosteronism	Hyperkalemia, gynecomastia
Carbonic Anhydrase	Inhibit carbonic anhydrase	Acetazolamide	Glaucoma, altitude sickness	Metabolic acidosis, hypokalemia
Osmotic Diuretics	Increase osmotic pressure in renal tubules	Mannitol	Cerebral edema, IOP	Pulmonary edema, dehydration