2. 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.
3. 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”
4. SITE OF
ACTION
TYPE OF
DIURETICS
EXAMPLES
1. SITE
DIURETICS
Carbonic anhydrase
inhibitors
Acetazolamide
, methazolamide
, dichlorphenamide
etc.
2. SITE
DIURETICS
Loop diuretics organomercurals,furos
emide,bumetanide,azo
semideetc
3. SITE
DIURETICS
Thiazide & thiazide like
diuretics
Chlorthiazide,
benzthiazide,
hydrochlorthiazide etc.
4. SITE
DIURETICS
Potassium-sparing
diuretics
Spironolactones
Triamterene,amiloride
5.OTHERS Osmotic diuretics Mannitol, Isosorbide,
glycerol
5. SITE 1 DIURETICS:
CARBONIC
ANHYDRASE INHIBITORS
MOA:INHIBITION OF
CAase
1. intracellularly
2. In luminal brush
border
effects:
reabsorption of
Na+,HNO3-
Seondary effect:
excretion of K+
USE:
1.Glaucoma
2.Promote exeretion of
weakly acidic drug
3. In epilepsy
4. Acute mountain
sickness
ADR:
1. metabolic acidosis
2.hypokalemia
3.20% in GFR
4.sulphonamide associat
ed hypersensitivity reactions.
6. SITE 2 DIURETICS:
HIGH- CEILING Or LOOP DIURETICS
MOA:
1.Inhibit the 1Na+/1K+/2Cl-
cotransport system
EFFECTS:
Reabsorption of Na+, K+,C l-
Use:
1.edemacardiac,hepatic,renal
2.Acute pulmonary edema
associated with CHF
3.HYPERCALCAEMIA & Renal
calcium stones
ADR:
1.Sulfnamoyl moiety associated
hypersensitivity reactions
2.Hypokalemia intensifies the
Toxicity of cardiac glycosidesSITE 2: Henle's loop
7. SITE 3 DIURETICS:
THIAZIDE DIURETICS
MOA:
All of these diuretics block the
Na+ reabsorption by inhibiting
The LUMINAL MEMBRANE
bound Na+/Cl- cotransport
system
Effects:
Naturetic,chloruretic,saluretic,
kaluretic& weak
bicarbonaturetic
Use:
1.edema associated CHF
2.hypertension(uncomplicated)
ADR:
1.Hypersensitivity reaction
2.Hypokalemia
3.cardiac output
8. 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 of
Luminal membrane
EFFECTS:
Na+,Cl- exeretion without
Concomitant increase in
urinary excretion rate of K+
USE:
1.Combination therapy with
site 2&3 diuretics
2.Mild edema associated CHF
3.HYPERTENSION
9. 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.