drugs and the kidney Flashcards
1
Q
what is best predictor of kidney functions
A
GFR
2
Q
what is GFR
A
sum of filtration across all the nephrons (ml/min)
3
Q
what is perfect way to measure GFR
A
give substance that is not secreted or reabsorbed and measure output in urine
4
Q
what are problems with using Crr
A
- can have slight variations despite stable GFR
- different assays give slightly different results
- actives SECRETED from proximal tubule
- tied to muscle mass
5
Q
2 uses of Cr
A
- use to measure clearance
- 24 hours - used to estimate GFR or clearance
- equations for both
6
Q
what is equation for clearance and issues
A
cockroft gault
- overestimate GFR when severely impaired
- imprecise when near normal
7
Q
4 variables used in estimating GFR
A
- age
- sex
- serum Cr
- race
8
Q
what is key to GFR estimation
A
need to be in steady state
9
Q
3 general classes of drugs that have a renal effect
A
- RAAS
- diuretics
- ADH
10
Q
3 main outcome of RAAS activation
A
- incr. aldosterone
- vasocontriciton
- increase Na reabsorbtion
11
Q
4 main drugs that affect the RAAS
A
- renin inhibitors
- ACEi
- ARB
- blockers of aldo - spironoloactone
12
Q
what are 4 main classes of diuretics
A
- carbonic anhydrase inhibs
- loops
- thiazide
- K sparing
13
Q
main actions of diuretics
A
- reduce Na content - reduce ECF
- increase Na excretion
- if proximal to CCD - K wasting
14
Q
action of carbonic anhydrase
A
- weak
- block in brush border of proximal tubule
- also excrete bicarb
15
Q
action of loops
A
- most potent
- can work with thiazides
- block reabsorbtion of Na in thick ascending loop
