Kidney and Diuretics Flashcards
3 functions of the kidney
- regulate extracellular body fluid volume
- maintain ion/pH balance in plasma
- excretion of foreign substances
- renin secretion
- activation of RAAS
5 groups of diuretics
- Carbonic Anhydrase Inhibitors
- Osmotic Diuretics
- Loop Diuretics
- Thiazides and Thiazine-Like Diuretics
- Potassium-sparing Diuretics
Name a carbonic anhydrase inhibitor
acetazolamide
effects of CAIs
moderate decrease in Na+ absorption mild plasma acidosis (due to H+ retention) urine alkalosis (due to bicarbonate secretion)
why is urine alkalosis good
increases the excretion of weak acids, so decreases the chance of crystallisation
what else can CAIs be used to treat
Glaucoma, as it decreases formation of AH)
where do CAIs predominantly work
proximal tubule
Example of a osmotic diuretic
mannitol
where do osmotic diuretics work
PCT, Descending Loop, Collecting Tubule (parts of the nephron which are freely permeable to water)
are these osmotic diuretics used often?
no
how do osmotic diuretics work?
increase the osmolarity of the tubular filtrate, so decreases water reabsorption
what else can osmotic diuretics be used in
cerebral oedema and glaucoma
most powerful group of diuretics
loop diuretics
2 examples of Loop Diuretics
furosemide and bumetanide
what symporter do loop diuretics work on
Na+/K+/2Cl- on luminal membrane
what effect do these have on the Na/K/2Cl symporter
inhibit reabsorption of these ions
another effect of loop diuretics
inhibit Mg/Ca reabsorption
Renal effects caused by Loop Diuretics
decreased Na reabsorption
decreased Cl reabsorption
increased K excretion
increased Ca and Mg secretion
therapeutics of Loop Diuretics
acute pulmonary oedema
chronic heart failure
renal failure
nephrotic syndrome
what is a side effect of Loop Diuretics
hypokalaemia (due to increased K excretion)
name 2 thiazides
hydrochlorothiazide and Bendroflumethiazide
name 3 thiazide-like diuretics
chlortalidone, indapamide, metolazone
where do thiazides/thiazide-like diuretics work
inhibit Na/Cl cotransporter
side effect of thiazides/thiazide-like diuretics
hypokalaemia
renal effects of thiazides/thiazide-like diuretics
decreased Na reabsorption
decreased Cl reabsorption
increased K excretion
increased Ca reabsorption
are these thiazides/thiazide-like diuretics strong?
moderate
after prolonged use what other effect can thiazides/thiazide-like diuretics have
vasodilating properties
how can thiazides/thiazide-like diuretics be used therapeutically
hypertension
mild heart failure
sever resistant oedema
prevention of kidney stone formation
adverse effects of thiazides/thiazide-like diuretics
hypotension, reduced plasma volume, hypokalaemia
what are 3 effects of hypokalaemia
tachyarrhythmias, hyperglycaemia, increased cardiac toxicity
how to potassium-sparing diuretics work
inhibit the effect of aldosterone
are potassium-sparing diuretics strong?
nope
how does aldosterone work?
increase synthesis of basolateral Na/K ATPase
increases activation and surface expression of luminal renal Na channels
what aldosterone would usually help do
Na taken in from lumen, then exported into the blood in exchange for a K, so K taken out of the blood (so normally result in hypokalaemia)
what are the 2 groups of potassium-sparing diuretics
- Mineralocorticoid (aldosterone) Receptor Antagonists (MRAs)
- Renal Na+ channel blockers
2 examples of MRAs
spironolactone and eplerenone
2 examples of renal Na+ channel blockers
amiloride and triamterene
the whole point of potassium-sparing diuretics
to block the effect of 2 receptors, so K stays in the blood
therapeutic uses of potassium-sparing diuretics
hypokalaemia, heart failure, treat aldosteronisms
adverse effect of potassium-sparing diuretics
hyperkalaemia
where do potassium-sparing diuretics
distal convoluted tubule
where does most water reabsorption happen
collecting duct
what increases the expression of Aqua-porin 2 on the luminal membrane
ADH
expression of Aqua-poring causes
increased water reabsorption
less pee/urine
decreases diuresis
