PHARMACOLOGY LAB – EX2: DIURETIC AGENTS
DIURETIC AGENTS DIURETICS THAT INCREASE THE GFR
• Diuretic - are drugs that increase the • This is further divided into xanthine
urine output and excretion of electrolytes derivatives and cardiac glycosides.
and water. For these desired effects to be • Xanthine derivatives - is composed of:
achieved, the animal must have o Caffeine
functional kidneys. o Theophylline
• Formation of urine is governed by the o Threobromine
processes of glomerular filtration, o Aminophylline
tubular resorption, and tubular secretion. • Cardiac glycoside - consists of digoxin
The bases for the action of diuretics are and digitoxin.
in coordination with the processes • These drugs increase the GFR through
mentioned. their action in renal circulation. They
• Clinically, this group of drugs is used to may inhibit sodium resorption, but cause
relieve edematous fluids that are of relatively mild diuresis by which potency
various causes. may vary among species and the drug
• Diuretics are classified into: being used.
o Osmotic diuretics • Xanthines - also cause CNS stimulation,
o Diuretics that increase the cardiac stimulation, and bronchodilation.
glomerular filtration rate • Digitalis glycosides - exert their diuretic
o Carbonic anhydrase inhibitors effect by improving the patient with
o Thiazides failing heart. For it to cause diuresis, the
o Loop of Henle diuretics patient must have a congestive heart
o Potassium-sparing diuretics failure.
OSMOTIC DIURETICS CARBONIC ANHYDRASE INHIBITORS
• Of all the osmotic diuretics, mannitol is • Acetazolamide, methazolamide,
the most useful. Following its dichlorphenamide, and ethoxolamide act
intravenous administration, it is filtered by inhibiting the carbonic anhydrase in
at the glomerulus and remained in the renal tubular cells, With the inhibition,
renal tubular fluid thereby osmotically decreased production of H- for Na+/H-
attracts large volumes of water which is exchange.
flushed top the kidneys. • Thus, Na+ remains in the tubular urine
o Its most common indication is for and attracts water osmotically causing
the treatment of cerebral edema. diuresis
o Other indications include • The characteristic large outpouring of
prophylaxis of acute renal HCO3- results in alkaline urine, and
ischemia and acute changes in eventually systemic acidosis.
renal tubular permeability • The major clinical use of this group of
excretion of certain poisons. drug is to relieve the increased
• Mannitol is contraindicated in intraocular pressure in glaucoma by
cardiovascular shock. reducing the rate of production of the
aqueous humor. Aside from this, they
also have antiepileptic effect.
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DIURETIC AGENTS DIURETICS THAT INCREASE THE GFR
• Diuretic - are drugs that increase the • This is further divided into xanthine
urine output and excretion of electrolytes derivatives and cardiac glycosides.
and water. For these desired effects to be • Xanthine derivatives - is composed of:
achieved, the animal must have o Caffeine
functional kidneys. o Theophylline
• Formation of urine is governed by the o Threobromine
processes of glomerular filtration, o Aminophylline
tubular resorption, and tubular secretion. • Cardiac glycoside - consists of digoxin
The bases for the action of diuretics are and digitoxin.
in coordination with the processes • These drugs increase the GFR through
mentioned. their action in renal circulation. They
• Clinically, this group of drugs is used to may inhibit sodium resorption, but cause
relieve edematous fluids that are of relatively mild diuresis by which potency
various causes. may vary among species and the drug
• Diuretics are classified into: being used.
o Osmotic diuretics • Xanthines - also cause CNS stimulation,
o Diuretics that increase the cardiac stimulation, and bronchodilation.
glomerular filtration rate • Digitalis glycosides - exert their diuretic
o Carbonic anhydrase inhibitors effect by improving the patient with
o Thiazides failing heart. For it to cause diuresis, the
o Loop of Henle diuretics patient must have a congestive heart
o Potassium-sparing diuretics failure.
OSMOTIC DIURETICS CARBONIC ANHYDRASE INHIBITORS
• Of all the osmotic diuretics, mannitol is • Acetazolamide, methazolamide,
the most useful. Following its dichlorphenamide, and ethoxolamide act
intravenous administration, it is filtered by inhibiting the carbonic anhydrase in
at the glomerulus and remained in the renal tubular cells, With the inhibition,
renal tubular fluid thereby osmotically decreased production of H- for Na+/H-
attracts large volumes of water which is exchange.
flushed top the kidneys. • Thus, Na+ remains in the tubular urine
o Its most common indication is for and attracts water osmotically causing
the treatment of cerebral edema. diuresis
o Other indications include • The characteristic large outpouring of
prophylaxis of acute renal HCO3- results in alkaline urine, and
ischemia and acute changes in eventually systemic acidosis.
renal tubular permeability • The major clinical use of this group of
excretion of certain poisons. drug is to relieve the increased
• Mannitol is contraindicated in intraocular pressure in glaucoma by
cardiovascular shock. reducing the rate of production of the
aqueous humor. Aside from this, they
also have antiepileptic effect.
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