Diuretics Flashcards
Osmotic Diuretics act on which part(s) of the nephron?
PT & DLH
acetazolamide acts on which part of the nephron?
PT
Furosemide acts on which part of the nephron?
TAL
hydrochlorothiazide acts on which part of the nephron?
DCT
amiloride & spironolactone act on which part of the nephron?
CD
Tolvaptan acts on which part of the nephron?
CD
how does mannitol reduce H20 & sodium reabsorption?
it increase the capillary oncotic pressure which will drive water & sodium out of the ICF and into the tubular lumen
What is the MOA of acetazolamide?
directly inhibits carbonic anhydrase
What is the MOA of furosemide?
blocks NKCC channels in TAL
What is the MOA of amiloride?
blocks ENaC channels in CD
What is the MOA of hydrochlorothiazide?
blocks NCC channels in DCT
What is the MOA of spironolactone?
MR receptor antagonist
What is the MOA of Tolvaptan?
acts on V2 receptors in CD to decrease sensitivity to aldosterone
What are the main clinical uses of mannitol?
decreases intracranial & intraocular pressure
How does acetazolamide decrease formation of uric acid stones?
It alkalizes the urine
How does inhibition of carbonic anhydrase affect the action of NHE channels in the PT?
It decreases Na+ & bicarbonate reabsorption and decreases H+ excretion
What are some of the AEs of acetazolamide?
exacerbation of calcium phosphate kidney stones; hyperchloremic metabolic acidosis; Type II Renal Tubular Acidosis
In addition to blocking NKCC channels, furosemide also activates what and how does this affect Na+ reabsorption?
Furosemide also activates PG synthesis which further decreases Na+ reabsorption in the kidneys
What is a major downstream effect of blocking NKCC channels in the TAL?
activation of RAAS system due to increased Na+ concentration in the tubular lumen
What are some of the main AEs of furosemide?
hypokalemia; hyponatremia; hypocalcemia; hypomagnesemia w/ chronic use; hypochloremia; metabolic alkalosis (caused by activation of RAAS); hyperuricemia
Explain how hydrochlorothiazide can be used to treat calcium phosphate kidney stones?
It increases Ca2+ reabsorption in PT & DCT thus reducing tubular Ca2+ concentration
Thiazides can also be used to treat which type of diabetes? Be specific.
Nephrogenic DI
What are relative contraindications for thiazide use?
hypochloremic metabolic alkalosis; Diabetes mellitus (thiazides can cause hyperglycemic & hyperlipidemia); Pts. on Li+ based antipsychotics (thiazides reduce Li+ excretion increasing risk for Li+ poisoning; can precipitate gout
How does amiloride prevent potassium wasting?
blockage of ENaC channels in CD disrupts Na+/K+ gradient that drives K+ secretion
What are the main clinical uses for amiloride?
Li+ induced DI (decreases Li+ reabsorption in CD); hyperaldosteronism
What are the main AEs of amiloride?
hyperkalemia; normal anion gap metabolic acidosis; Type IV renal tubular acidosis
What are the main clinical uses of Tolvaptan?
polycystic kidney disease; SIADH; hyponatremia
