Diuretics Flashcards
what are diuretics, what do they do and what are they used for?
- help get extra fluid off (h2O & Na+)
- decrease BP due to dec. in plasma volume
- used for HTN, Heart Failure, ARF, Edema
what are drug targets for how they get moved across the membrane?
- anything with a protein
what are the different classes of diuretics on general?
- SOA (loops)
- Efficacy (high ceiling)
- structure (thiazide)
- effect K+ excretion (potassium-sparing)
what are classes based off of MOA?
- inhibit CA
- osmotic
- inhibit Na/K/Cl symport
- inhibit Na/Cl symport
- inhibit renal epithelial Na+ channel
- MAR
where does high protein binding occur?
- not filtered through bowmans capsule
- transport/secretion in proximal tubule
where does drug get secreted?
PT
where does drug get reabsorped?
DT
what is filtered in the glomerulus?
unbound protein
what is the major route of elimination for drugs and what percent?
- renal excretion
- 25-30%
what drugs are OATs?
diuretics
penicillin
cephalosporin
probenecid
NSAIDs
what are OATs and what do they do?
- diffusion out of capillary into interstitial space
- transport across basolateral membrane
- secretion across luminal membrane
– COMPETITION; NON_SELECTIVE
what does active secretion depends on?
- amount of plasma protein binding
- the rate of delivery
- degree of saturation of transporters
- presence of competitive drugs
what is penicillin and mechanism?
- inhibit transpeptidase
- block crosslinking
- dec. cell wall synthesis
- extracted and used with competition of probenacid to slow excretion and prolong activity
what do inhibitors of carbonic anhydrase doing?
- inhibit both cytoplasm and membrane-bound
- block reabsorption of NaHCO3
what does the sulfanilamide group in CA inhibitors and other diuretics?
show to produce mild diuresis
what is a common diuretics that inhibits CA?
acetazolamide
how is acetazolamide good for acute mountain sickness?
- used before going above 10.000 ft
what percent hav an occurance of sulfonamide induced drug rash?
5-10% but rare
what are osmotic diuretics?
- inert
- major site PCT & descending loop of henle
what is mannitol?
- loss of water
- reduced intracellular volume
- hypernatremia risk
what osmotic diuretics are IV?
mannitol
urea
what osmotic diuretics are orally active?
- isosorbide
- glucose
- glycerine
what are inhibitors of Na/K/1Cl symport diuretics?
- loop diuretics and high ceiling diuretics
- act on luminal symport and must be in lumen for diuretic activity
- reduce uric acid secretion
what is ethacrynic acid?
a loop diuretic not derived from sulfonamides
what are some in the loops class?
- lasix
- bumentanide
- torsemide
what are toxicities of loop diuretics?
- hypokalemic metabolic alkalosis
- ototoxicity
what class is inhibitors of Na/Cl symport?
thiazides
where do thiazides act?
on the distal tubule, proximal tubule second
how do you make thiazides from basic structure?
by an acylating agent
how do you make hydrothiazide from basic strucutre?
aldehydes or ketones
what are some drugs in the thiazide class?
- chlorothiazide
- hydrochlorothiazide
- chlorthalidone
- metolazone
where do potassium sparing diuretics act?
on the late distal tubule and collecting duct
what are toxicities and contraindications for potassium sparing diuretics?
- toxic:
- hyperkalemia - contraindications
- K+ supps
- ACE inhibitors
what are MRA diuretics?
- aldosterone antagonists, potassium sparing
- only diuretics that do not act within the tubular lumen
- some toxic and contraindications as above
what drugs are in this class of MRA?
- spironolactone
- eplerenone
what is the braking phenomenon?
- activation of RAAS and SNS
– Na excretion exceeds intake = ECFV dec. = new SS
– when diuretic D/C, ECFV&BW rise where Na+ exceeds excretion and new SS achieved activating Breaking Phenomenon
what drugs are in the K+ sparing duiretics
– Na+ channel inhibitors class?
- amiloride
- triamterine
what diuretics are used in combos with others since they are weak normally?
- potassium sparing Na+ channel inhibitors
what does adding more that diuretics from a different class with differ MOA do?
is more effective
what is the excretion pattern of triamterene like with electrolytes?
has Na and Cl but no K
what is the excretion pattern of lasix like with electrolytes?
all across the board
what is the excretion pattern of spironolactone like with electrolytes?
no calcium and some bicarb
what is the excretion pattern of spironolactone like with electrolytes?
no potassium
what is the excretion pattern of isosorbide like with electrolytes?
lots of bicarb
what is the electrolyte distribution like and body ph for diuretics?
how do you draw a thiazide?
how do you draw lasix?
how do you draw bumetanide?
how do you draw ethancrynic acid?
how do you draw osmotic diuretics
how do you draw acetazolamide
