-
What are the functions of the kidney?
- 1. Waste excretion
- 2. Electrolyte balance
- 3. Regulation of extracellular fluid volume
- 4. Acid base balance
- 5. Drug and hormone metabolism
- 6. Blood pressure regulation
- 7. Calcium/phosphate balance regulation
-
What is the general action of most diuretics?
- Increase the excretion of Na+ and water
- Decrease the reabsorption of Na+ and Cl- from the filtrate
- Increased water loss is secondary to increased excretion of NaCl
-
What are diuretics used to treat?
- Hypertension
- Glaucoma
- Salt/water overload associated with:
- Nephrotic syndrome
- Heart failure
-
What is the therapeutic goal of diuretics?
Increase excretion of salt and water.
-
What transport mechanisms are used in the nephron?
- Active transport
- Diffusion
- Ion channels
- Counter transporters (antiport)
- Cotransporters (symport)
-
Exchange systems and their place in the nephron
- Na+/H+ exchanger---------Proximal Tubule
- Na+/K+ ATPase-----------Whole Nephron
- Na+/K+/2Cl- cotransporter---Loop of Henle
- Na+/Cl- cotransporter--------Distal tubule
-
What are the 4 kinds of diuretics?
- Loop
- Thiazide
- Potassium sparing
- Carbonic anhydrase
-
Give an overview of loop diuretics
- Mechanism: Bind to Cl- part of Na+/K+/Cl- transporter, inhibiting it.
- Result: increase Na+ excretion
- increase Mg2+ excretion
- increase Ca2+ excretion
- increase K+ excretion
- decrease uric acid excretion
- Side effects: Hypokalaemia
- Metabolic alkalosis
- Prerenal uremia
- Tinnitus
- Uses: Treatment of salt and water overload associated with
- pulmonary oedema
- heart failure
- renal failure
- nephrotic syndrome
-
Give an overview of thiazide diuretics
- Mechanism: bind to the Cl- part of the Na+/Cl- cotransport system in the distal tubule, to inhibit it.
- Result: increase Na+ excretion
- increase Mg2+ excretion
- increase K+ excretion
- decrease Ca2+ excretion
- Side effects: Hypokalaemia
- Hyperglycaemia
- Metabolic alkalosis
- Prerenal uremia
- Uses: Hypertension
- Mild heart failure
-
Give an overview of potassium sparing diuretics
- Not used primarily as diuretics, rather they are used in conjunction with loop or thiazide diuretics to minimise risk of hypokalaemia.
- Spironolactone is an aldosterone antagonist, inhibits Na+ retention and K+ secretion.
- Amiloride blocks sodium channels to inhibit Na+ reabsorption.
- Side effect: Hyperkalaemia
-
Give a summary of Carbonic anhydrase inhibitors
- No longer used as diuretics
- Used in glaucoma to decrease intraocular pressure.
- Inhibit the carbonic anhydrase to increase excretion of Na+, K+ and bicarbonate.
- Side effects: Metabolic acidosis and Alkaline urine
|
|
