Diuretics Flashcards
What is the general aim of any diuretic
To diminish sodium reabsorption at different point in the nephron
Increase urinary sodium and water loss
At which point in the loop of Henle is there the highest concentration
The bottom of the loop
What is the overall aim of the counter-current mechanism in the loop of Henle
To create an electrical gradient
What is reabsorbed in the proximal tubule
glucose, aa, phosphate
What moves out of the descending limb of the loop of henle
water
What moves into the ascending limb of the loop of henle
potassium
hydrogen Nh3
Name the 5 classes of diuretic
- Carbonic anhydrase inhibitors
- Loop
- Thiazide
- Potassium sparing diuretics
- Osmotic diuretics
Name a type of carbonic anhydrase diuretic
Acetazolamide
Where do CA diuretics work
Proximal convuluted tubule
Usual role of carbonic anhydrase enzyme
- Converts H2C03 to H20 and CO2 in the lumen
- Converts CO2 and H20 into H2CO3 in the pct
How do carbonic anhydrase inhibitors work as diuretics
Inhibits transport of bicarbonate out of the proximal convuluted tubule into the interstitium
Leads to less sodium reabsorption and therefore greater sodium bicarbonate and water loss in the urine
What are the real life main uses of acetazolamide
- Glaucoma
- Epilepsy
- Mountain Sickness
What are the side effects of carbonic anhydrase inhibitors
- Metabolic acidosis
- Sedation
- Bone marrow suppresion
Name 2 loop diuretics
Fresemide
Bumetanide
Where do loop diuretics work
Ascending limb of loop of henle
Which transporter does the loop diuretic block
Na+/ K+/ 2cl- sympoter
How do loop diuretics work
- Block Na+/ K+/ 2Cl- sympoter
- Inhibits uptake of these
- Loop diuretics also inhibit potassium and calcium uptake because their uptake is reliant on charge
- Prevents loop from becoming hypertonic so reduces osmotic charge
- Increased urine production
What is excreted in loop diuretics
Potassium, sodium, water, magenesium
What are some indications for loop diuretics
Hypertension
Heart failure
Volume overload from CKD
Side effects of loop diuretics
Hypokalaemia
Dehydration
Kidney stones
Deafness
Name 2 thiazide diuretics
Bendroflumethiazide
Hydrochlorothiazide
Where do thiazide diuretics work
Blocks Na+/Cl- transporter in distal convuluted tubule
Main uses for thiazide
Antihypertensive
Reduces plasma volume and peripheral resistance
Side effects of thiazide diuretics
Hypokalaemia Hypocalcaemia Hyponatraemia Hyperglycaemia Hypercholsteroaemia
2 types of potassium sparing diuretics
Epithelial Na channel antagonists
Aldosterone antagonists
Name 2 epithelial sodium channel antagonists
Amiloride
Triamterene
Name 2 aldosterone antagonists
Spironolactone
Eplerenone
What does amiloride target
Na+ channel in the collecting tubule
By blocking transport, more sodium is excreted by spares potassium loss
Indications to use amiloride
Heart failure
Hypokalaemia from other diuretics
Cirrhosis
Side effects of amiloride
Hyperkalaemia
Hyponatraemia
Indications to use aldosterone blockers
Hyperaldosteronism
Heart failure
Hypokalaemia
Cirrhosis
Side effects of aldosterone blockers
Hyperkalaemia
Glynecomastia
Hyponatraemia
Define osmotic diuretic
Any osmotically active molecule that is freely filtered from the glomerulus and not reabsorbed by the tubules
Name an osmotic diuretic
Mannitol
Clinical indications for using osmotic diuretic
Cerebral oedema
Oliguric acute renal failure
Side effects of osmotic diuretics
Transient fluid overload
Pulmonary oedema
When should you not use any diuretic
Hypotension
Dehydration
POST SURGERY
When should you not use loop/ thiazide diuretics
When hypokalaemic
When should you not use amiloride/ aldosterone antagonists
When hyperkalaemic
