Biogenic Sulfur Gases as Biosignatures on Temperate Sub-Neptune Waterworlds
Pharmacology of diuretics-antidiuretics
1. DIURETICS AND
ANTI-DIURETICS
BY
DR N. LAKSHMI SUDEEPTHI, M.PHARM, PH.D
ASSISTANT PROFESSOR,
DEPT OF PHARMACOLOGY
KVSR SIDDHARTHA COLLEGE OF PHARMACEUTICAL
SCIENCES, VIJAYAWADA.
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2. CONTENTS
Introduction to diuretics
Renal pharmacology
Diuretic & antidiuretic drugs
Classification
Mechanism of action (MOA)
Therapeutic uses
Adverse drug reactions (ADRs)
Contraindications
Drug interactions
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3. DIURETICS
Diuretics, also called water pills, are medications designed to increase
the amount of water and salt expelled from the body as urine.
a) Increase output of urine
b) change urine pH and ionic composition of the urine and blood
Primary indications are hypertension and mobilization of edematous
fluid (e.g. kidney problems, heart failure, cirrhosis of liver, diabetes
insipidus, pregnancy and nutritional deficiencies)
Mainly promotes the excretion of the salts like Na+ , Cl-, HCO3
- and
water
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4. RENAL PHARMACOLOGY 4
Kidneys:
• Represent 0.5% of total body weight, but
receive ~25% of the total arterial blood
pumped by the heart
• Each contains from one to two million
nephrons:
– The glomerulus
– The proximal convoluted tubule
– The loop of Henle
– The distal convoluted tubule
5. RENAL PROCESSES
The nephron uses four mechanisms to convert blood
into urine:
Filtration
Reabsorption
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12. DIURETIC DRUGS
I. Drugs that modify salt excretion:
A. PCT: Carbonic anhydrase inhibitors
B. TAL: Loop diuretics
C. DCT: Thiazides
D. CCT: Potassium sparing diuretics
E. Osmotic diuretics: Mannitol
II. Drugs that modify water excretion:
A. Osmotic diuretics: Mannitol
B. ADH agonists: Desmopressin
C. ADH antagonists: Conivaptan, Demecloycline, Lithium
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13. CARBONIC ANHYDRASE INHIBITORS
Carbonic anhydrase inhibitors reduce the activity of carbonic anhydrase, an
enzyme responsible for catalyzing the reaction between carbon dioxide and water
into carbonic acid and then bicarbonate.
Carbonic anhydrase inhibitors decrease the secretion of aqueous humor which
results in a decrease in intraocular pressure.
ACETAZOLAMIDE:
Can trigger metabolic acidosis
Weak diuretic
Primary indications is glaucoma
DORZOLAMIDE
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14. Mechanism of Action
A carbonic anhydrase inhibitor reduces formation of hydrogen and bicarbonate ions from carbon
dioxide and water by inhibiting the enzyme carbonic anhydrase in proximal renal tubule, thereby
promoting renal excretion of sodium, potassium, bicarbonate, and water.
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18. OSMOTIC DIURETICS
Osmotic diuretics are solute causes water to be retained within the proximal tubule and
descending limb of loop of Henle (freely permeable to water) through osmosis.
EX-Mannitol , urea
Properties :
not metabolized
freely filtered at the glomerulus
Pharmacologically inert
Increase plasma & tubular fluid osmolality
Administered by IV
Oral administration results in an osmotic diarrhea-- perhaps useful to promote
elimination of toxic substances from the GI tract (in conjunction with activated charcoal)
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19. Mechanism of action
Mannitol induces diuresis because it is not reabsorbed in the renal tubule, thereby
increasing the osmolality of the glomerular filtrate, facilitating excretion of water.
Mannitol extract water
from intracellular
compartments, reducing
total body water.
Following IV administration,
intracranial pressure
falls within 60-90 minutes.
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23. LOOP DIURETICS
Loop diuretics are diuretics that act at the ascending limb of the loop of Henle in the
kidney.
Also called HIGH CEILING DIURETICS.
Examples:
Furosemide (Lasix)
Torsemide (Demadex)
Bumetanide (Bumex)
Ethacrynic acid (Edecrin)
Given by oral or IV route
Duration- 2 to 4 hours; given twice a day
IV administration increases renal blood flow & PGE2 synthesis in kidney
dilates vascular smooth muscles, local protective effect.
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24. Mechanism of action
Loop diuretics are a powerful type of diuretic that work by inhibiting the sodium-potassium-chloride
(Na+/K+/2Cl) co-transporter in the thick ascending loop of Henle .
This reduces sodium, chloride and potassium reabsorption, leading to increased loss of sodium, chloride,
potassium and phosphorus into the nephron.
As a result, water is also drawn
into the nephron and urine
volume increases.
Loop diuretics also reduce
the reabsorption of
calcium and magnesium.
Potent renin releaser.
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28. THIAZIDE DIURETICS
Thiazides are usually used for their blood pressure lowering effects because their diuretic activity
is relatively weak compared to some other types of diuretics.
Thiazides – Chlorthiazide
Hydrochlorthiazide
Hydroflumethazine
Benzthiazide
Cyclothiazide
Thiazide analogues (like thiazides but does not have thiazide rings )
• Chlorthalidone
• Metolazone
• Indapamide
• Chlorexolone
• Clopamide
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29. Mechanism of Action
They act by inhibiting the sodium/chloride cotransporter located in the distal convoluted tubule
of a nephron (the functional unit of a kidney).
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33. POTASSIUM SPARING DIURETICS
Potassium-sparing diuretics are medicines that increase diuresis (urination) without the loss
of potassium.
They are generally weak diuretics and work by interfering with the sodium-potassium exchange
in the collecting tubule of the kidneys or as an antagonist at the aldosterone receptor.
Examples:
• Eplerenone (Inspra)
• Spironolactone (Aldactone)
• Triamterene (Dyrenium)
• Amiloride
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34. Mechanism of action
These diuretics prevent K+ secretion by antagonising the effects of aldosterone (spironolactone,
eplerenone) or by inhibiting sodium influx (amiloride , triamterene).
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38. ANTI-DIURETICS
An antidiuretic is a substance that helps to control fluid balance in
the body by reducing urination, opposing diuresis.
Particularly in diabetes insipidus which is their primary indication.
The major endogenous antidiuretics are antidiuretic hormone
(ADH; also called vasopressin)
Human ADH is rich in arginine ,so also called as arginine
vasopressin.
EXAMPLES :
Vasopressin, Desmopressin, Lypressin, Felypressin,Terlipressin,
Argipressin, Pitressin, Syntopressin
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