diuretics

1. DIURETICS

2. • Drugs which cause a net loss of
sodium and water in urine
Diuretics

3. Classification
1. High efficacy diuretics (Inhibitors of Na+-
K+- 2Cl-
cotransport)
e.g. Furosemide , bumetanide , ethacrynic acid
2. Medium efficacy diuretics ( Inhibitors of
Na+- Cl-
symport)
e.g. Chlorothiazide, benzthiazide , indapamide,
chlorthalidone

4. Classification (contd..)
3. Weak or adjunctive diuretics
a) Carbonic anhydrase inhibitors :Acetazolamide
b) Potassium sparing diuretics :
Spironolactone, triamterene , amiloride
c) Osmotic diuretics : Mannitol, glycerol

5. HIGH-EFFICACY (LOOP) DIURETICS
Site of action – thick ascending limb of
Loop of Henle
•Inhibit the luminal Na+
-K+
-2Cl-
transporter - reduce reabsorption of
NaCl
•Prevent reabsorption of Ca2+
and Mg2+

6. Therapeutic uses of loop diuretics
Acute pulmonary edema – i.v. furosemide
Renal edema
Hypertension associated with renal failure
& congestive heart failure
 Hypercalcemia & renal calcium stones
 Hyperkalemia
 Forced diuresis – in cases of poisoning

7. • Medium efficacy diuretics
• Site of action – distal convoluted
tubule
 Block Na+
/ Cl-
transporter – inhibit NaCl
reabsorption
 Increase Ca2+
reabsorption
THIAZIDE DIURETICS

8. Uses
• Mild hypertension
• Edema associated with CHF/ kidney
disease
• Hypercalciuria /osteoporosis

9.  Hypokalemia
 Hyponatremia
 Hyperuricemia - attacks of gout
 Hyperglycemia
 Hyperlipidemia
 Hypocalcemia – loop diuretics;
hypercalcemia – thiazides
 Ototoxicity – esp. ethacrynic acid
 GIT disturbances
 Allergic reactions
Adverse effects of high ceiling &
thiazide diuretics

10. III. Carbonic anhydrase inhibitors
 Acetazolamide, dorzolamide
 Site of action – Proximal convoluted tubule
 Inhibits carbonic anhydrase activity -
decreases HCO3
-
reabsorption - alkaline
diuresis

11. Therapeutic Uses
• Glaucoma: acetazolamide, dorzolamide
• Urinary alkalinization : UTI ; to promote
excretion of certain acidic drugs
• Metabolic alkalosis
• Acute mountain sickness

12. Adverse effects
• Acidosis
• Renal stones
• Hypokalemia
• Drowsiness , fatigue
• Hypersensitivity reactions

13. POTASSIUM SPARING DIURETICS
• Site of action - Late distal tubule & collecting
duct
Spironolactone – aldosterone antagonist
 Competitively inhibit the binding of
aldosterone to mineralocorticoid receptor
inhibits formation of aldosterone-induced
proteins (AIPs) – prevent sodium
reabsorption and potassium excretion

14. Therapeutic uses:
 Hyperaldosteronism (cardiac failure, liver and
kidney disease, Conn syndrome)
 Hypertension (with thiazide /loop diuretics)
Adverse effects:
 Hyperkalemia
 Drowsiness, confusion
 Abdominal upset
 Impotence
 Menstrual irregularities

15. OSMOTIC DIURETICS
• Mannitol
Freely filtered at the glomerulus
Not reabsorbed at the renal tubules
Relatively inert pharmacologically
Non - metabolizable
Increases plasma osmolarity
• Decrease sodium reabsorption
• Dilute tubular fluid and increase water
excretion

16. USES:
1.Head injury or stroke
2.Glaucoma
3.In cases of poisoning
3.To maintain g.f.r. and urine flow in patients
with impaired renal function
A/E: Headache, nausea, vomiting
Excessive plasma volume expansion –
pulmonary edema

17. Thank you