Diuretics Flashcards
carbonic anhydrase inhibitors prevent the reabsorption of what
HCO3 (bicarb)
Example of osmotic diuretic?
Mannitol
pt w/ osteoporosis and mild HTN needs diuretic. What would be best choice
thiazide diuretic
*acts on DCT and Ca++ is being reabsorped (better for osteoporosis). Only one that has vasodilatory effect on vasculature.
1st line drugs for HTN
Can always trust ACE.
CCB, ARBs, Thiazide diuretics, ACEI
Will aldosterone antagonists cause hypokalemia?
Nope
Can cause hyperK+
Why should a pt taking furosemide not take an NSAID for their h/a?
Blockage of prostaglandin synthesis reduces efficacy of loop diuretics
What 2 drugs do you not take NSAIDs with?
-ACEIs
-Loop diuretics
NSAIDs constrict the ________ arteriole in the kidney
afferent
Angiotensin II constricts the ________ arteriole in the kidney
efferent
Which diuretic for pt w/ mineralocorticoid excess?
Spironolactone
*acts on aldosterone (aldosterone antagonist) and aldosterone is a mineralocorticoid
Loop diuretics block which cotransporter?
N/K/2Cl
Defeciency in parathyroid hormone (PTH) causes what electrolyte imbalance?
Low Ca++
___________ diuretics & _________ __________ antagonists are aquaretics and are not directly natriuretic
-Osmotic diuretics
-ADH antagonists
What 3 compounds/ions get reabsorbed in the proximal convoluted tubule (PCT) of the kidney?
-Na+ (65% of Na+ get reabsorbed here)
-H2O
-HCO3 (Bicarb)
What compound/ion gets reabsorbed in the descending limb of the loop of henle in the kidney?
H2O
What 2 compounds/ions get reabsorbed in the ascending limb of the loop of henle?
-Na+ (25% of Na+ reabsorption occurs here)
-H2O
What 2 compounds/ions get reabsorbed in the early distal convoluted tubule (DCT) in the kidney?
-Na+ (5%)
-H2O
What 2 compounds/ions get reabosorbed in the late distal convoluted tubule (DCT) and collecting duct (CD), and what 2 substances are required for the reabsorption to occur?
-Na+ (5%)
-H2O
*Aldosterone is required here for Na+ reabsorption and ADH is required for H2O reabsorption to occur. This is the differrence between the early & late DCT and why K+ sparing diuretics work here in the late DCT.
*K+ also gets excreted largely in the CD
What part of the tubule do thiazide diuretics work on?
Early DCT (5% of Na+ reabsorption)
What is MOA of mannitol (osmotic diuretic). AKA why does is cause massive aquaresis.
Mannitol is a large molecule that is able to get filtered throught the glomerulus into the tubules. Because its so large though, in the tubules it can’t be reabsorbed into the blood and it creates a strong osmotic pressure, pulling H2O into the tubules. Since the H2O gets pulled into the tubules it gets excreted via ureters.
What part of the tubule does Mannitol (osmotic diuretic) work?
-PCT
&
-Desc. limb of loop
What diuretic drug works soley on the PCT?
Carbonic anhydrase inhibitors (CAIs)
What is the MOA of CAIs?
Blocks the enzyme carbonic anhydrase which dissasociates HCO3 (into H2O & CO2) via the buffer equation in order for it to be reabsorbed. When it gets absorbed into the cell (the wall of the PCT, on the way to the bloodstream) it dissasociates back into HCO3 + H+ and the H+ drives the Na+ pump that reabsorbs Na+.
With the enzyme and this pump inhibited, the reabsorption of HCO3, Na+, and H2O is blocked.