B - 23. Potassium sparing diuretics, ADH antagonists, osmotic diuretics Flashcards
Main goal of diuretics
To increase the production of urine and the elimination of H2O, metabolic wastes and electrolytes from our body
Where does potassium sparing diuretics act?
Distal conv. tubule + collecting ducts
Principal cells and a-intercalated cells
Main effect of potassium sparing diuretics
Na+ and water excretion increased, potassium excretion decresed
Main indications for diuretics
Main: Hypertension and edematous states, heart failure
K+-sparing diuretics role in treatment
They are weak, and mostly used in combination with loops or thiazides to reduce the potassium wasting
Aldosterone receptor antagonsits
Spironalactone
Eplerenone
Indications for potassium sparing diuretics besides HT and edema
- Hyperaldosteronism (primary and secondary)
- Decreases post-MI mortality
- Spirolactone can also inhibit testosterone binding (polycystic ovary syndrome)
ENaC blockers
Amiloride
Side effects of potassium sparing diuertics
- Hyperkalemia -> arrythmia (should never be given with ACEi’s or ARB’s who cause H+ retention -> changing blood pH)
- Spirolactone can give antiandrogen effects like gynecomastia due to blocking testosterone
Osmotic/aquaretic diuretics names
Mannitol
Glycerol (rarely used)
Osmotic/aquaretic diuretics indications and SE
Increases H2O excretion without the loss of electrolytes
Indications:
- glucoma
- head trauma
- need for “flushing” away harmful substances like hemoglobin and myoglobin in hemolysis and rhabdomyolsis respectively
SE:
- can worsen edematous states as blood volume initially gets bigger
- Hyponatremia in renal and heart failure
- Dehydration -> Hypernatremia, hyperkalemia
ADH antagonists; names
Tolvaptan
ADH antagonists; use, SE
Blocking ADH will block the upragulation of aquaporin 2 channels, thus decreasing water reabsorption
Used to treat hyponatremia, SIADH (syndrome of inapproriate antidiuretic hormone)
SE:
- Hypotension
- Hypernatremia
- Renal failure
