drugs and the kidney Flashcards
(33 cards)
what is GFR
sum of the filtration across all the nephrons - ml/min
where is creatinine actively secreted from
the proximal tubule
Creatinine always
OVERESTIMATES GFR (it’s GFR + tubular secretion)
The Cockcroft-gault equation predicts
creatinine clearance
when is the CG equation imprecise?
at near normal GFR - imprecise
When does the CG equation overestimate GFR?
when renal function is severely impaired
what does the CG equation incorporate that is helpful when person like Arn shwatz comes in?
it incorporates weight into the equation
what are the four variables used to estimate GFR in MDRD and CKD-EPI?
Age
Sex
Serum creatinine
Race
MDRD tends to
UNDERESTIMATE GFR
All equations depend on creatinine being
in steady state
Angiotensin 2 is the
active form of angiotensin
3 functions of Angiotensin 2
- increase aldo
- vasoconstrict
- increase sodium reabs
which drugs work at the proximal convoluted tubule?
CAinhibitors
Thiazides work at which level of the kidney
distal convoluted tubule
any drugs that work proximal to the cortical collecting duct cause
potassium wasting
how do the carbonic anhydrase inhibitors work?
they result in increased distal delivery of bicarb
how do loop diuretics work?
Block the Na2ClK pump
block reabsorption of sodium, so increase its delivery distally
how do thiazides work
work at the distal CT, block NaCl channel
2 mechanisms of action of potassium sparing diuretics
block aldo binding
bind the ENaC
how do vaptans work?
promote waterloss, block ADH
Pre-renal AKI can be caused by which drugs
- diuretics
- RAAS blockade
- NSAIDs
How do NSAIDs cause pre renal AKI
- they cause relative constriction of the afferent arterioles (blocking PGs)
especially when combined with an ACE i
2 drugs that can cause ATN
- aminoglycosides and IV contrast
need to adjust drug ? to avoid toxicities
dose and frequency