DIURETICS

by SROTA DAWN.

B.PHARM(3RD YEAR)

Definition: A diuretic can be defined as a chemical that increases the rate of urine formation. The PRIMARY ACTION: Direct inhibition of Na+ transport along one or more of the four major anatomical sites.

4 major sites of nephron

:

SITE 1 : The “PCT”

SITE 2 : The thick ascending limb of

“HENLE’s LOOP”

SITE 3 : The “DCT”

SITE4:The“collecting tubule & cortical collecting Tubule”

Classification of diuretics according to there SITE OF ACTION

SITE OF ACTION

TYPE OF DIURETICS

EXAMPLES

1. SITE DIURETICS

Carbonic anhydrase inhibitors

Acetazolamide , methazolamide , dichlorphenamide etc.

2. SITE DIURETICS

Loop diuretics organomercurals,furosemide,bumetanide,azosemideetc

3. SITE DIURETICS

Thiazide & thiazide like diuretics

Chlorthiazide, benzthiazide, hydrochlorthiazide etc.

4. SITE DIURETICS

Potassium-sparing diuretics

SpironolactonesTriamterene,amiloride

5.OTHERS Osmotic diuretics Mannitol, Isosorbide,glycerol

SITE 1 DIURETICS: CARBONIC ANHYDRASE INHIBITORS MOA:INHIBITION OF CAase 1. intracellularly2. In luminal brush border effects:reabsorption of

Na+,HNO3- Seondary effect: excretion of K+ USE: 1.Glaucoma2.Promote exeretion of

weakly acidic drug3. In epilepsy4. Acute mountain sicknessADR:1. metabolic acidosis 2.hypokalemia 3.20% in GFR 4.sulphonamide associat ed

hypersensitivity reactions.

SITE 2 DIURETICS:

HIGH- CEILING Or LOOP DIURETICS

MOA:1.Inhibit the 1Na+/1K+/2Cl-

cotransport systemEFFECTS:

Reabsorption of Na+, K+,C l-

Use:1.edemacardiac,hepatic,renal2.Acute pulmonary edema

associated with CHF3.HYPERCALCAEMIA & Renal

calcium stonesADR:

1.Sulfnamoyl moiety associated hypersensitivity reactions

2.Hypokalemia intensifies the Toxicity of cardiac glycosidesSITE 2: Henle's loop

SITE 3 DIURETICS:

THIAZIDE DIURETICS

MOA:

All of these diuretics block the Na+ reabsorption by inhibitingThe LUMINAL MEMBRANE bound Na+/Cl- cotransport system

Effects:Naturetic,chloruretic,saluretic,kaluretic& weak

bicarbonaturetic

Use:1.edema associated CHF2.hypertension(uncomplicated)

ADR:1.Hypersensitivity reaction2.Hypokalemia3.cardiac output

SITE 4 : COLLECTING TUBULE&CORTICAL COLLECTING TUBULE

SITE 4 DIURETICS:

POTASSIUM SPARING DIURETICS

MOA:SPIROLACTONEs: inhibit reabsorption of Na+ by compititively inhibiting the actions of ALDOSTERONE

OTHERS: Plug the Na+ channels ofLuminal membrane

EFFECTS:Na+,Cl- exeretion withoutConcomitant increase in urinary excretion rate of K+

USE:1.Combination therapy with site 2&3 diuretics2.Mild edema associated CHF3.HYPERTENSION

OTHERS:

MANNITOL: High luminal fluid concentration of mannitol create an osmotic effect .this effect prevents the reabsorption of Water.

Use:Used in hospital setting to keep the nephrons open.Decrease CSF volume & pressure.

THANK YOU