Diuretics

Diuretics

Written by Dr Andrew Lam

Frusemide

Mechanism of Action: Blockage of Na-K-Cl Co-Transporter

Class: Loop Diuretic

Site of Action: Thick Ascending Loop of Henley

Uses: Congestive cardiac failure, Oedema of renal or hepatic origin, Ascites

Starting Dose: 20mg BD IV or PO

Side Effects: Electrolyte abnormalities (hypokalemia, hypernatremia), hypotension and metabolic alkalosis

Spironolactone

Mechanism of Action: Aldosterone antagonist

Class: Potassium Sparing Diuretic

Site of Action: Collecting ducts

Uses: Ascites, Oedema, Prevention of cardiac remodelling

Starting Dose: 25mg Daily PO

Side Effects: Electrolyte abnormalities (hyperkalemia, hyponatremia)

Hydrochlorothiazide

Mechanism of Action: Blockage of Na/Cl Symporter

Class: Thiazide

Site of Action: Distal Convoluted Tubule

Uses: Hypertension, Oedema 

Starting Dose: 25mg Daily PO

Side Effects: Hypotension, Hypokalemia, Hyponatremia

Acetazolamide

Mechanism of Action: Carbonic Anhydrase Inhibitor

Site of Action: Proximal Convoluted Tubule

Uses: Acute Angle Glaucoma, Altitude Sickness, Metabolic Alkalosis

Starting Dose: 125-250mg BD PO or IV

Side Effects: Metabolic acidosis, paraesthesias, hypokalemia