Diuretics C8 Flashcards
(16 cards)
What are diuretics
drugs that increase urine production
used in heart failure, kidney failure, cirrhosis of liver - where there is fluid retention as a symptom
what are the different classes of diuretics?
loop
thiazide
potassium sparing
MOA loop diuretics (furesomide, bumetanide)
site: thick ascending limb in looop of henle.
action: inhibit sodium, potassium. cloride transporter = decrease in electrolyte reabsorbtion ( sodium as well as potassium and chloride reabsorbtion)
due to high conc of electrilytes in nephron, there is less movement of water out and therefore more water lost as urine
MOA thiazide like diuretics (bendroflumethazide)
site: distal convuluted tubule
action: inhibition of socium/chloride symporter
= decreased reabsorbtion of sodium and chloride
MOA mineralcorticoid receptor antagonist (eplenerone, spironaloctone)
site: collecting duct
action: block aldoserone receptors
mineralcortocoid reptors usually are activated by aldosterone leading to increased Na reabsrbtion and potassium secretion. spironalacton/epleneone exhibit their effects by blocking this receptor and stopping aldosterone binding = lwss sodium reabsorbtion and potassium secretion and therefore less water reabsorbtion from the collecting duct
why can loop diuretics cause Hypokalaemia
Hyponatremia
Hypomagnesemia
inhibit reabsorbtion of electrolytes (Na. K, Cl) from thick ascending limb into blood (MOA)
this means there is less magnesium reabsorbition further alsong nephron also
why can thiazide like diuretics cause Hypokalaemia
Hyponatremia
hypokalemia:
as a result of downstream effects of lack of Na reabsorbtion. = more Na in collecting duct. the secretion of potassium and reabsorbtion of sodium in the collecting duct is linked
hyponatremia: inhibits sodium reabsorbtion
moniroting following the initiation of a diuretic
U&Es: in particular sodium, potassium and magnesium
renal function using crcl and egfr
blood pressure
ensure the person is educated on fluid balance
when should diuretics be taken
not before bed as they will make you need to urinate during sleep = sleep disturbances
of someone has nausea and vomiting whilst on a diuretic what advice should we give them
stop taking whilst they experience this
dehydration and electrolyte imbalances
what is natriuresis
excretion of sodium in the urine
why are loop diuretics used in hypertension
causes decrease in NaCl entry into macula densa tubular cells
promotes renin release, decreasing angiotensin II activity
are thiazide like diuretics effective in renal impairment
no
need to be renally secreted to act on DCT
can patients on potassium sparing diuretics have potassium supplements?
no
can cause severe hyperkalaemia
adverse effects of thiazide diuretics
postural hypotension
hyperglycaemia
hypokalaemia
electrolyte imbalances
GI disturbances
dizziness and headache
adverse effects of spironolactone
AKI
confusion
dizziness
electrolyte disturbances
GI disturbances
