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Clinical pharmacy 2024/2025 Level 3 Pharm D Pharmacology 1 (PO 502)

1- Diuretics

Definition:
 Drugs that increase the volume of urine by increasing water & solute excretion.
 These agents are mostly inhibitors of renal ion transporters

General MOA
+
 inhibit the reabsorption of Na natriuresis (increase sodium excretion in urine)
+
K kaliuresis (increase K+ excretion in urine) and other electrolytes from the
nephron into circulation by active and passive processes that involve ion channels,

transport proteins.
 Types of transport protein: (symporters) transport 2 or more ions in the same
direction & (antiporters) transport ions in opposite directions.

Sites of action & classifications

Classes Site of action MOA

Inhibit reabsorption of HCO3 
Carbonic anhydrase Proximal convoluted  its excretion  mainly for
inhibitors tubules
glaucoma & high-altitude sickness.

Inhibit Na , K , 2Cl cotransporter
+
-
+
Ascending loop of proteins  hypokalemia 
Loop diuretics
Henle * C/I in kidney stones as they  Ca2+
excretion.

Inhibit reabsorption of Na & Cl, but
Distal convoluted
Thiazide diuretics  Ca excretion  safely used in
tubules
kidney stones.

Block Na-channels or aldosterone
K-sparing diuretics Collecting tubules antagonists  excretion Na & spare
K  safely used in HF.

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