17.diuretics

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 Ca
2+
and Mg
2+

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 Ca
2+
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 HCO
3
-
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