duretics Flashcards
generally speaking what do diuretics do ?
they increase the urine output
what is the mechanism of sodium regulation ?
through RAAS and ADH
what is the effect on volume with increased sodium excretion ?
volume loss
where is potassium secreted from ?
in the distal tubule and the collecting duct
what effect do diuretics have on potassium levels ?
cause hypokalemia due to increased urine flow
what is the MOA of carbonic anhydrase inhibitors ?
inhibit the enzyme and so more bicarb is excreted along with more sodium
what is an example of CA ?
acetazolamide
what is the side effect of using acetazolamide ?
causes non AG metabolic acidosis
paraesthesia
sulfa allergy
causes kidney stones
what are the clinical uses of acetazolamide ?
glaucoma
severe metabolic alkalosis
pseudotumor cerebri ( increased ICP)
prevention of high altitude sickness
why does acetazolamide cause kidney stones ?
reduces urinary citrate excretion in the urine
increases occurence of calcium kidney stones
where does CAI have its effect in the nephron ?
in the PCT
where do osmotic diuretics work in the nephron ?
in the thin ascending limb
what are the differences in concentration of the urine along the nephron ?
in the PCT - isotonic
in the descending loop - hypertonic
in the ascending limb - hypotonic
DCT - continues to be hypotonic
in the collecting duct - with ADH urine becomes very concentrated
without ADH urine becomes very dilute
what is an example of an osmotic diuretic ?
mannitol
which is freely filtered by the glomerulus
what is the main use for mannitol ?
cerebral edema
glaucoma
goal is to create a hyperosmolar state
what are the contraindications associated with mannitol ?
cannot be used in heart failure
cannot be used in extreme renal disease , causes anuric renal failure
what is the MOA of loop diuretics ?
inhibit the sodium potassium chloride pump
what happens to serum osmolality and ADH levels in response to mannitol ?
increase in serum osmolality and increase in ADH levels
what are the mechanisms that promote diuresis in loop diuretics ?
increased sodium excretion
decreased medullary osmotic gradients
what are examples of loop diuretics ?
furosemide
what are the side effects associated with loop diuretics ?
hypokalemia
hypocalcemia
hypomagnesemia
ototoxicity
AIN
gout is promoted by diuretics
what is the acid base problem associated with loop diuretics ?
metabolic alkalsosis
what is the MOA of thiazide diuretics ?
they work on the DCT of the nephron
inhibit sodium and chloride reabsorption
if we need a loop diuretic in a patient with a sulfa allergy what do we use ?
ethacrythic acid
