DIURETICS

Presentation by- Syed Baseeruddin Alvi M.Pharm-Pharmacology(09)

INTRODUCTION

• Diuretics are the drugs which causes a net loss of sodium and water in urine

• They are used to reduce the abnormal accumulation of excess fluid in the body

• act to modulate different processes to reduce sodium and water reabsorption, resulting in increased water excretion

How can all diuretics show same action…….?

A sneak peek into the nephron…….!

Types of diuretics…….

Carbonic anhydrate inhibitors…….

• An enzyme – interconvertion b/w carbon di oxide and carbonic acid

• Site of action – PT• Na+ is carried by Na+/H+ antiport• Energy comes from down hill

moment of Na+

Acetazolamide

Dichlophenamide

Osmotic diuretics……. Glycerin Mannitol

Site of action – loop of Henle

It shows action by two ways

1. Extracts water from interstitial spaces

2. Extracts water from intracellular compartment

Increasing osmolarity of the filtrate

Reducing blood viscosity & medullary osmotic gradient

High ceiling diuretics(inhibitors of Na+/K+/2Cl- symport)…

Site of action – Thick ascending limb

Flux of ions is mediated by symporter

Overall transport causes extraction of

Nacl from lumen to medullary spaces

Transported Nacl is responsible in

generating & maintaining medullary

osmotic gradient

Inhibits the reabsorption of up to 25% of Na+, hence known as high ceiling Furosemide

Bumetanide

Inhibitors of Na+/Cl- symport…….

• They are also known as thiazide or

thiazide like diuretics.

• Site of action – Distal tubule

• Symporter moves Cl- into the cell

against its electrical gradient (active)

• Na+ entry is passive where as exit

is active process.

• Thiazides fight for Cl- binding site…

• Moderately effective (i.e 5%)

Hydrochlorothiazide Metolazone

Inhibitors of renal epithelial Na+ channels….

• They are known as k+ sparing diuretics

• Site of action – late distal tube &

collecting duct

• Na+ influx provides driving force for

secretion of k+

Amiloride

Triamterene

Antagonist of mineralocorticoid receptor….

ADR

AD ADRC

AIP

Inactive Na+ channels get activated

spironolactone

lumen Interstitial space