4 Flashcards
Where is Na reabsorbed in the kidney? (4)
1) Proximal convoluted tubule
2) Loop of Henle
3) Distal convoluted tubule
4) Collecting duct
What do loop diuretics work on
Na/K/2Cl
What do thiazides work on
Na/Cl
What do K sparing diuretics
Na channels
What is the proposed mechanism by which thiazide administration mediates its effect long term
Direct vasodilation
What are examples of loop diuretics
frusemide (lasix)
bumetanide (burinex)
What is the MOA of loop diuretics
Inhibits Na/K/2Cl transporter and decrease water reabsorption in the collecting duct
What are some of the other salts that can also be lost using loop diuretics
MARKED DIURESIS
K, H, Ca2+ and Mg2+
What are some clinical uses of loop diuretics
Oedema
Hypertension
Heart failure
Hypercalcaemia
What is oedema
Swelling of a tissue that results from excessive accumulation of fluid within the tissue
What are examples of thiazides
Hydrochlorothiazide (Dithiazide)
Indapamide (Natrilix or Dapatabs)
What salts are lost from using thiazides + which salt has a decreased loss
MODERATE DIURESIS
Na, H2O, K and H loss
Ca2+
Clinical uses of thiazide diuretics
Hypertension
Heart failure
Prevention of recurrent stone formation in idiopathic hypercalciuria
What is the MOA of spironolactone
Blocks actions of aldosterone
Aldactone/Spiractin
What is the MOA of amiloride
Blocks Na+ channels
component of Moduretic
What is the effect of K+ sparing diuretics + salts lost
MILD DIURESIS
Decreased K+ and H+ loss
Little effect on Ca2+ and Mg2+`
What is a clinical use of amiloride
Used with K+ losing diuretics to prevent K+ loss
What is a clinical use of spironolactone
Hyperaldosteronism and heart failure
What is transepithelial potential difference
Voltage across an epithelium
Why do loop and thiazide diuretics cause K+ and H+ loss
Increased delivery of Na downstream results in increased Na+ reabsorption in LDT/CD
Increased Na+ reabsoprtion increases activity of Na/K ATPase and ive transepithelial potential difference in LDT/CD
How do diuretics work as antihypertensives (3)
Decrease in extracellular fluid volume and hence blood volume
Direct vasodilatory effect
Decreased vascular reactivity (sensitivity to noradrenaline and AngII reduced)
Which diuretic is most potent
Loop diuretic
