diuretics(mode of action) and anti diuretics-

diuretics(mode of action)

potassium sparing diuretics

a)Aldosteron antagonist

ex:Amphenone _Spironolactone(Aldoctone is trade name )

Note:similar to aldosteron in chemical structure.

mode of action:competes with aldosteron for its receptors site in distal convoluted tubule and collecting duct which results in inhibition Na re-absorption,so excretion of water increases because Na attracts water

b)non aldosteron diuretics

ex:Amiloride (more potent and rapid onest)

Note:used combination with thiazide derivatives and loop diuretics.

mode of action:it inhibits Na/K exchange directly

cardiovascular diuretics

ex: xanthine derivatives(theophylline - aminophyline)

    cardiac glycosides(strophanthus )

Note: have diuretic effect secondary to thier effect on cardiovascular system

mode of action:1-cardiac stimulation increase cardiac out put

                         2-improve circulation 

                         3-dilatation renal blood vessels increases glomerular filteration rate 

                         4-diuresis   

used in:cardiac and renal odema

acidifying diuretics 

ex:Ammonium chloride (NH4CL)Solutions of ammonium chloride are mildly acidic  and CaCl

NH4CL--------->NH3+H+CL

mode of action:acidification to urine

used to :correct alkalosis for excretion of basic drugs as amphetamine.

mercural diuretics

ex:salygran -mersalygran

Note:rarely used and give alkaline urine so it is contraindication in equine

mode of action:1-decrease CL re-absorption 

                         2-decrease Na re-absorption

                         3-decrease water re-absorption

Anti diuretics

ex:petressin tannate-ADH-synthetic ADH

definition :drugs decreases excretion of water

.

mode of action:stimulation anti diuretic hormone which result in re-absorption water from tubules 

used in: treatment diabetes incipedus (disease characterized with increase amount and frequency of urination especially during night caused by insufficient ADH anti diuretic hormone)