What is it ?

Lasix. oral + IV forms.
loop diuretic. selectively inhibit NaCl reabsorption in the Thick Ascending Loop (TAL)

PHARMACODYNAMICS

Thick ascending loop of Loop of Henle

inhibit NKCC2, the luminal Na+/K+/2CL-transporter in the TAL of Henle’s loop.
hence :
a. REDUCING the reabsorption of NaCl
b. also diminish the lumen-positive potential that comes from K+ recycling >>>> increase in M+ and Ca2+ excretion

induce expression of cyclooxygenases (COX-2) >>>more synthesis of PG from AA

increases renal blood flow via PG actions on kidney vasculature

PHARMACOKINETICS

rapid absorption.
eliminated via glomerular filtration + tubular secretion.
duration of effect ~2-3 hours.

CLINICAL INDICATIONS

Acute pulmonary oedema

Acute hypercalcemia.

Hyperkalaemia

Acute Renal Failure

Anion OVerdose

TOXICITY

Hypoklaemic Metabolic Alkalosis

Ototoxicity

Hyperuricemia

Hypomagnesemia

Allergic reactions

MCQ questions :

3. which is NOT true of diuretics?

a. Loop diuretics can be used to treat hypercalcaemia

b. Frusemide is used in the prophylaxis of acute mountain sickness

c. Cirrhotic oedema responds to spironolactone

d. They may enhance the efficiency of ACE inhibitors

e. Hydrochlorothiazide is useful in diabetes insipidus

ANSWER : B

Viva questions : http://lifeinthefastlane.com/exams/facem-primary/pharmacology-viva/pharm20100212/