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Definition and Classification of Diuretic


  1. INTRODUCTION Diuretics are used in the management of edema associated with cardiovascular, renal, and endocrine abnormalities, as well as in the treatment of hypertension, glaucoma, and several other clinical disorders. The drugs act at various sites in the nephron to cause diuresis (an increase in urine production). Most diuretics inhibit the reabsorption of sodium from the nephron into the circulation and thereby increase natriuresis (the excretion of sodium in the urine).
  2. 3. ClASSIFICATION Thiazide Diuretics  Chlorthiazide  Hydrochlorthiazide Loop Diuretics  Furosemide  Ethacrynic acid Potassium sparing Diuretics  Spirinolactone  Amiloride  Triamterene Carbonic Anhydrase Inhibitors  Acetazolamide  Dorzolamide
  3. 4. STRUCTURES Thiazide Diuretics Chlorthiazide Hydrochlothiazide
  4. 5. Loop Diuretics Furosemide Ethacrynic acid
  5. 6. Potassium sparing diuretics Triamterene Spirinolacton e
  6. 7. Osmotic diuretic Mannitol Glycerine
  7. 8. Carbonic Anhydrase Inhibitors Acetazolamide
  8. 9. MECHANISM OF ACTION Loop diuretics inhibit the Na+,K+,2Cl− symporter in the ascending limb of the loop of Henle and thereby exert a powerful natriuretic effect. In comparison with other diuretics, loop diuretics can inhibit the reabsorption of a greater percentage of filtered sodium. Loop diuretics are sometimes called high-ceiling diuretics because they produce a dose-dependent diuresis throughout their clinical dosage range.
  9. 10. In addition to their natriuretic effect, the loop diuretics produce kaliuresis by increasing the exchange of sodium and potassium in the late distal tubule and collecting duct via the same mechanisms as those described for the thiazide diuretics. Loop diuretics also increase magnesium and calcium excretion by reducing the reabsorption of these ions in the ascending limb
  10. 11. ADVERSE EFFECTS  Loop diuretics can produce a variety of electrolyte abnormalities, including  hypokalemia  hypocalcemia  hypomagnesemia  metabolic alkalosis.  Also increase blood glucose and uric acid levels in the same manner as the thiazide diuretics.  use of loop diuretics causes ototoxicity with manifestations such as tinnitus, ear pain, vertigo, and hearing deficits. In most cases the hearing loss is reversible.
  11. 12. SAR OF LOOP DIURETICS  They are either 5-sulphamoyl-2-amino benzoic acid or 5- sulphamoyl-3-amino benzoic acid derivatives.  The carbonyl group at C-1 provides optimal diuretic activity. The substitution of activating group (X) in the position 4 by Cl, alkoxy, aniline, benzyl, or benzoyl group at 4th position increases the diuretic activity. The presence of sulphamoyl group in the 5th position is essential for activity. The two series of 5-sulphamoyl benzoic acid differ in the nature of the functional group that substi- tuted in 2nd and 3rd position.
  12. 13. The presence of furfuryl, phenyl, and thienyl methyl group at 2nd amino group of 5-sulphomoyl  -2-amino benzoic acid gives maximum diuretic activity. The wide range of alkyl group can be substituted at 3rd amino group of 5-sulfamoyl-3-amino ben- zoic acid without modifying the optimal diuretic activity. A molecule with a weakly acidic group to direct the drug to the kidney and an alkylating moiety to react with sulphydryl groups and lipophilic groups seemed to provide the best combination of a diuretic in the class.
  13. 14. USES Diuretic actions of Loop Diuretics:  Oedema due to cardiac failure, hepatic disease, nephrotic syndrome.  Acute pulmonary edema & cerebral edema, pregnancy & idiopathic edema.  Acute chronic renal failure.  Barbiturate poisoning, salicylate poisoning.
  14. 15. Nondiuretic action of Loop Diuretics:  As an antihypertensive.  Idiopathic calcium urolithiasis.  In Hypocalcaemia.  Diabetes insipidus.
  15. 16. Several types of diuretics also increase kaliuresis (the excretion of potassium in the urine) and affect the excretion of magnesium, calcium, chloride, and bicarbonate ions.
  16. 17. SYNTHESIS Furosemide