pharmacology of drugs acting on renal system
TRANSCRIPT
PHARMACOLOGY OF DRUGS ACTING ON RENAL SYSTEM
BHARAT INSTITUTE OF TECNOLOGY
Mr.B.CHAKRAPANI M.pharm (ph.D)ASSISTANT PROFESSOR
DEPARTMENT OF PHARMACOLOGY
MANGALAPALLY,IBRAHIMPATNAM(M), R.R Dist.
Anatomy of urinary system
Anatomy of urinary system
CortexGlomeruli
MedullaRenal tubules
(with calyces forming the medulary pyramids)
UreterTakes urine to bladder
Blood carried to the kidney by the renal artery and taken away
by the renal vein.
Cortex
Medulla
Renal artery
Renal vein
Renal pelvis
Ureter
Renal hilum
Anatomy of the Kidney
Anatomy of the Urinary System
Kidneys(urine formation)
Lower Urinary TractUreters (2)Bladder (1)Urethra (1)
(urine collection, storage, excretion)
Urinary system organs
Kidney Functions
1. Regulation of water, electrolyte balance, pH
2. Removal of waste from blood and excretion of urine.
3. Secretion of hormones Erythropoietin Renin Vitamin D3
Each KIDNEY consists of 1 million NEPHRONS
Each nephron consists of a:GLOMERULUS (found in cortex)
forms a protein-free filtrate from bloodTUBULE (found in medulla)
processes the filtrate to form urine
Each TUBULE consists of several segments:Proximal tubuleLoop of HenleDistal Tubule
Collecting Ducts.
Pharmacology of drugs acting on Renal System
Diuretics are drugs that increase the excretion of Na+ and water from the body by an action on the kidney.
Their primary effect is to decrease the reabsorption of Na+ and Cl- from the filtrate, increased water loss being secondary to the increased excretion of NaCl.
This can be achieved by: a direct action on the cells of the nephron indirectly modifying the content of the filtrate.
Note that the diuretics which have a direct action on the cells of the nephron (with the exception of spironolactone ) act from within the tubular lumen and reach their sites of action by being secreted into the proximal tubule.
Classification of Diuretic drugs
Carbonic an hydrase inhibitors:AcetazolamideLoopdiuretics:Bumetanide,Ethacrynicacid,Furosem
ide,Torsemide.Thiazidediuretics:Cholorothiazide,Chlorothalidone,
Hydrocholorothiazide,Indapamide,Metolazone. potassium-sparingdiuretics:
Amiloride,Spirnolactone,TriamtereneOsmotic diuretics:Mannitol,urea,
DIURETICS ACTING DIRECTLY ON THE CELLS OF THE NEPHRON
Drugs that cause NaCl loss by an action on cells must obviously affect those parts of the nephron where most of the active and selective solute reabsorption occurs:
the ascending loop of Henle the early distal tubule the collecting tubules and ducts.
Loop diuretics
Loop diuretics are the most powerful of all diuretics, capable of causing 15-25% of the Na+ in the filtrate to be excreted .
They are termed 'high ceiling' diuretics and their action is often described-in a phrase that conjures up a rather uncomfortable picture-as causing 'torrential urine flow'. The main example is furosemide; others are bumetanide, piretanide, torasemide and etacrynic acid.
These drugs act primarily on the thick segment of the ascending loop of Henle, inhibiting the transport of NaCl out of the tubule into the interstitial tissue by inhibiting the Na+/K+/2Cl- carrier in the luminal membrane
DIURETICS ACTING DIRECTLY ON THE CELLS OF THE NEPHRON
Drugs that cause NaCl loss by an action on cells must obviously affect those parts of the nephron where most of the active and selective solute reabsorption occurs: the ascending loop of Henle the early distal tubule the collecting tubules and ducts.
Clinical uses of loop diuretics
Loop diuretics are used in conjunction with dietary salt restriction and often with other classes of diuretic , in the treatment of salt and water over load associated with
Acute pulmonary edemaChronic heart failureCirrhosis of the liver complicated by Ascites.Nephrotic syndromeRenal failureTreatment of hypocalcaemia after replacement of
plasma volume with intra venous NaCl solution.