Diuretics: Types, Mechanism & Clinical Uses.pptx

Diuretics are medications that promote urine production by increasing the excretion of sodium and water from the kidneys. They are commonly used to manage conditions like hypertension, heart failure, edema, and certain kidney disorders. Diuretics are classified into loop diuretics (e.g., furosemide), thiazide diuretics (e.g., hydrochlorothiazide), potassium-sparing diuretics (e.g., spironolactone), and osmotic diuretics (e.g., mannitol), each with specific mechanisms and clinical applications. Proper use is essential to prevent electrolyte imbalances and dehydration.

1. Diuretics Dr. Anto Rajiv, Junior Resident, Department of Pharmacology and Therapeutics, KGMU, Lucknow

2. Kidney Excretion of wastes Acid-base homeostasis Osmolality regulation Blood pressure regulation Hormone secretion Functional unit - Nephron

3. Renal Physiology The excretion by kidney is dependent on the following: Glomerular filtration Receive 25% of Cardiac output Filtration rate: 100-120 ml/min 180L of glomerular filtrate/day Tubular reabsorption Reabsorption of 99% of glomerular filtrate only + 1ml/min excreted as urine Tubular secretion

4. Proximal tubules: Reabsorption of 60-70% Na + Permeable to water Iso tonic urine Isosmotic reabsorption of amino acids, glucose, cations Loop of Henle: Thin descending limb: most active water reabsorption Thick ascending limb: Reabsorption of Na + Water impermeable Diluting segment

5. Distal tubules: Na + reabsorption Collecting duct: selectively water permeable

6. Diuretics Di uretics cause loss of Na + and H 2 O in urine Aquaretic cause loss of H 2 O only

7. Classification of Diuretics Osmotic Diuretics Carbonic Anhydrase inhibitors Loop diuretics Thiazides Potassium sparing diuretics

8. Osmotic Diuretics I ncrease tubular fluid  osmolarity, pulling water into the   collecting tubules   and preventing water reabsorption, which results in  Osmotic Diuresis These can act in any place in nephron Includes mannitol Uses Acute congestive glaucoma Cerebral edema Incipient renal failure

9. Contra-indications Cerebral Hemorrhage Acute renal failure Pulmonary edema

10. Carbonic Anhydrase Inhibitors Acts on proximal tubule Inhibits Carbonic anhydrase (non-competitive but reversible) Causes loss of Na + and HCO3 - in urine Na + and H 2 O Diuresis HCO 3 Urinary alkalosis/Metabolic acidosis Have self-limiting action Include: Acetazolamide, Brinzolamide, Dorzolamide etc

11. Indications Angle closure glaucoma Alkalinization of urine Mountain sickness Epilepsy

12. Adverse effects Metabolic Acidosis Hypokalemia (maximum hypokalemia at equally natriuretic doses) Parasthesia Renal stones Contra-indication Liver disease

13. Loop Diuretics Acts on thick ascending limb of loop of Henle Inhibit Na + H + 2Cl - symporter Include: Furosemide, Torsemide, Bumetanide etc High ceiling diuretics Uses Edema (CHF etc) Bromide and Iodide poisoning Hypercalcemia contraindicated in patients with  hypokalemia (only to be administered after correction), severe hyponatremia, hypotension, azotemia , oliguria/anuria, and hepatic coma

14. Thiazides Act on early distal tubule Inhibits Na + -Cl - symporter Include: Methiazide , Polythiazide, Chlorthiazide Thiazide -like diuretics: Chlorthalidone, Indapamide, Metolazone

15. Side effect of both Thiazides and Loop diuretics: - Na + , K + , Mg 2+ , H + - Glucose, Uric acid, Lipids Loop diuretics - Ca 2+ (used in Hypercalcemia) Thiazides - Ca 2+ (used in Osteoporosis and recurrent renal calcium stones)

16. Uses Hypertension Edema Recurrent renal calcium stones Bomide and Iodide poisoning Osteoporosis Diabetes Insipidus Metolazone is effective in renal failure unlike other thiazides

17. K + Sparing Diuretics Acts on Collecting tubules Aldosterone receptor antagonists Spironolactone Epleronone Epithelial Na + channel blockers Triamterene Amiloride These drugs cause Diuresis, Hyp er kalemia and Metabolic acidosis Spoironolactone cause Gynaecomastia

18. Uses Conn’s syndrome Edema in cirrhosis Prevent Hypokalemia from other diuretics Congestive Heart Failure Resistant Hypertension

19. All diuretics work from luminal side EXCEPT Aldosterone antagonists which work from Basolateral side

20. THANK YOU