Diuretics Flashcards
function of diuretics
increase urine output by increasing Na excretion
factors affecting diuretic efficacy
- site of action/MOA
- response of other nephron segments
- pharmacokinetics
indications for diuretic use
- maintain urine flow
- mobilize inappropriate ECF stores (move edema/ascites out of the body
- correct ion imbalances
- hypertension
- excrete toxins
adverse effects of diuretics
- hyponatremia
- dehydration
- hypokalemia (K wasting)
- hyperkalemia (K sparing
what is an example of an osmotic diuretics
mannitol
MOA of osmotic diuretics
increases filtrate osmolality to draw water into tubules
site of action of osmotic diuretics
entire tubule length
mostly PCT and LOH
are osmotic diuretics K wasting or sparing
K wasting
MOA of carbonic anhydrase inhibitors
inhibits carbonic anhydrase to decrease HCO3 reabsorption and H+ excretion, leading to decreased Na reabsorption on basolateral membrane
site of action of carbonic anhydrase inhibitors
PCT and collecting ducts
are carbonic anhydrase inhibitors K wasting or sparing
K wasting
what is an example of a loop (high ceiling) diuretic
furosemide
site of action of loop (high ceiling) diuretics
thick ascending LOH
MOA of loop (high ceiling) diuretics
inhibits NKCC2 (Na/K/Cl cotransporter)
are loop (high ceiling) diuretics K wasting or sparing
K wasting
MOA of thiazide diuretics
inhibits Na/Cl cotransporters
site of action of thiazide diuretics
DCT
are thiazide diuretics K wasting or sparing
K wasting
MOA of K Sparing diuretics
blocks ENaC channels to decrease Na uptake and K excretion
site of action of K Sparing diuretics
late DCT and collecting ducts
are K Sparing diuretics K wasting or sparing
K sparing
MOA of aldosterone antagonists
competitively binds aldosterone receptors
site of action of aldosterone antagonists
late DCT and collecting ducts
are aldosterone antagonists K wasting or sparing
K sparing
short term tolerance
develops after the first or second dose
body tries to resolve the sudden decrease in ECF volume by activating RAAS and sympathetic nervous system
long term tolerance
develops after chronic use
repeated delivery of high [Na] filtrate to DCT and CD causes cells to hypertrophy and increase their reabsorptive capacity
