4. INTRODUCTION
Diuresis means the production of urine.
Diuretics are substances whose administration
increases urine production.
Practical definition of a diuretic is a drug which
increases the renal excretion of salt and water.
Diuretics are commonly known as “Water Pills”
5. GENERAL USES OF DIURETICS
Diuretics are used to treat diseases which are
associated with increase of Extracellular Fluid
Volume, such as
Hypertension
Edema
Congestive Heart Failure
HOW
Diuretics increases Urinary Output thus
lower/decreases the extracellular fluid volume.
7. SEVEN TYPES
1. Osmotic diuretics.
2.Diuretics which inhibit active reabsorption of
electrolytes.
3. Diuretics which inhibit action of aldosterone.
4.Diuretics which inhibit activity of carbonic
anhydrase.
5.Diuretics which increase glomerular filtration
rate.
6. Diuretics which inhibit secretion of ADH.
7. Diuretics which inhibit ADH receptors.
8. OSMOTIC DIURETICS
Osmotic diuretics are the substances that induce
osmotic which occurs because of increased osmotic
pressure.
Consider the Osmotically active substances that
are not reabsorbed from renal tubules. When
injected in large quantities into the body, these
substances increase the osmotic pressure in the
tubular fluid in turn reduces water reabsorption.
Results into excretion of excess of water through urine.
Examples; Urea, Mannitol, Sucrose and Glucose.
9. DIURETICS WHICH INHIBITS ACTIVE
REABSORPTION OF ELECTROLYTE
RELY ON POSITION/PART OF NEPHRON
▶ LOOP DIURETICS – They act on the thick ascending loop of
Henle. They inhibit Sodium and Chloride reabsorption.
Examples; Furosemide and Torasemide.
▶ PROXIMAL PART OF DCT – They inhibit Sodium reabsorption and
usually called “Thiazide” Example is Metolazone
▶ DISTAL PART OF DCT AND COLLECTING DUCT – They inhibit
reabsorption of Sodium and excretion of Potassium. They are
also referred to as the potassium-retaining diuretics or
potassium sparing diuretics.
10. DIURETICS WHICH INHIBITS ACTION OF
ALDOSTERONE.
Some diuretics inhibit sodium reabsorption and potassium
excretion in the distal convoluted tubule and collecting
duct, by inhibiting the action of aldosterone.
These substances are also called the potassium retaining
diuretics or aldosterone antagonists.
Examples
i. Spironolactone
ii. Eperenone.
11. DIURETICS WHICH INHIBITS ACTIVITY OF
CARBONIC ANHYDRASE
Some diuretics inhibit the activity of carbonic
anhydrase in proximal convoluted tubules and
prevent reabsorption of bicarbonates from renal
tubules, resulting in osmotic diuresis. Such diuretic
agents are called carbonic anhydrase inhibitors.
Acetazolamide is a carbonic anhydrase inhibitor.
12. DIURETICS WHICH INCREASES
GLOMERULAR FILTRATION RATE
Some Xanthines (alkaloids, used as
mild stimulants) cause diuresis by
increasing the glomerular filtration
rate and to some extent by
decreasing the sodium reabsorption.
13. DIURETICS WHICH INHIBITS SECRETION
OF ANTIDIURETIC HORMONE (ADH)
Some diuretics produce diuresis by
inhibiting the secretion of ADH.
Examples
i. Water
ii. Ethanol.
14. DIURETICS WHICH INHIBITS SECRETION
OF ANTIDIURETIC HORMONE RECEPTORS
The antagonists of V2 receptors
cause diuresis by inhibiting the
receptors of antidiuretic
hormone, thereby preventing the
activity of this hormone.
15. ABUSES OF DIURETICS
Nowadays, diuretics are misused in order to reduce
the body weight and keep the body slim. Even
persons suffering from eating disorders attempt to
reduce body weight by misusing the diuretics.
Prolonged use of these substances leads to
complications like syndrome of diuretic-dependent
sodium retention, characterized by Edema. The
adverse
effects depend upon the type of diuretic agents
used.
