05.20 - Drugs and Renal Fxn (Sweatman) Flashcards Preview

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Flashcards in 05.20 - Drugs and Renal Fxn (Sweatman) Deck (52):
1

2 peptide-like drugs

beta-lactams, ACEi's

1

Though inward conductance is greater than outward, K efflux does not occur b/c

Vm is more positive than EK

2

What provides driving force for K excretion in DT epithelial cells

Na absorption --> Depolarizes membrane

3

Tx for hyperkalemia is required if

EKG changes

4

What mediates reabsorption of peptide-like drugs

Peptide Transporters (PEPT1, PEPT2)

5

Capacity rate limited

Extraction ratio is limited by the reversible binding of the drug to plasma proteins or its location in RBCs

5

NSAID use in CKD will cause

Acute reductions in renal bloodflow and GFR

6

PGI2/PGE2 preserve GFR by antagonizing arteriolar vasoconstrictors and

blunting mesangial and podocyte contraction

7

Drugs that antagonize ___ increase risk of AKI when NSAID is administered

Drugs that antagonize RAAS

8

Effect of PG's on RAAS

Stimulate Renin secretion --> Enhance Na retention and K secretion

8

Effect of PG's on ADH

Inhibit cAMP synthesis and oppose ADH --> Water excretion

10

What provides driving force for reabsorptio of drugs and drug metabolites

Extensive reabsorption of filtered water

11

Why doesn't K efflux thru ROMK at physiological intracellular Mg

Intracellular Mg binds ROMK and blocks K efflux

12

T/F: PGs are a primary regulator of renal function

False, minimal importance in kidney of health individuals with normal volume status

12

What can be used to remove K+ in patients with renal failure

Dialysis

12

Low magnesium can exacerbate ___ by ___

K wasting by incr K secretion in DT

13

Most common cause of drug-induced hypokalemia

Anti-infective agents

14

Effect of PGI2 and PGE2 in kidney

Vasodilation of interlobular arteries, afferent and efferent arterioles, and glomeruli

14

Effects of PG's on LOH and Distal Nephron

(1) Incr renal Na excretion, decr medullary tonicity; (2) Stimulate Renin secretion; (3) Inhibit cAMP and oppose ADH

14

Acute NSAID toxicity is manifest in terms of

Tubular Epithelial Necrosis secondary to altered renal hemodynamics

15

Anti-infective agents commonly cause what electrolyte abnormality

HypoKalemia

16

Diureti-induced hypokalemia is associated with

Mild-Moderated Metabolic Alkalosis

18

2 commonly used formulas that estimate GFR

Cockroft-Gault; MDRD

18

Effect of PGE2 on cellular transport of NaCl

Decreases cellular transport of NaCl --> Increase Na excretion and decr in medullary tonicity

20

Kidney PGs have their major role in

preservation of renal fxn when pathologic states supervene and compromise physiologic kidney processes

21

3 steps in hyperkalemia tx

(1) Calcium Gluconate, (2) Shift to intracellular, (3) Removal of excess K+

23

Risk of NSAID-associated AKI in health persons

Low, b/c PG production is low in healthy persons

24

Second most common cause of drug-induced hypokalemia

Diuretics

26

Net effect of PG actions on LOH and Distal Nephron is that chronic NSAID consumption can lead to

a mild, dose-dependent increase in BP

28

Tubular secretion occurs primarily in

pT

28

GFR > ___ is normal

80

29

At physiological intracellular Mg concentration, ROMK conducts K in which direction

Inward

30

Perfusion rate limited

extraction ratio is not limited to the unbound fraction of drug

30

COX-2 inhibitor effects on kidneys

equivalent to other classes with respect to their nephrogenic potential

31

NSAIDs are also associated with interstitial nephritis that is thought to be result of

Allergic reaction

32

GFR < ___ is severe renal impairment

30

34

3 conditions with increased prevalence that are exacerbated by GFR

HTN, CHF, Renal insufficiency

35

Organic anion and cation transporter systems, w/ overlapping specificities, allow potential for

Drug-Drug interactions

35

How does insulin lower hyperkalemia

Stimulates Na/H exchange --> Na in --> Stimulates Na/K --> Uptake of K into cell

36

PG production is increased in ___ disease

chronic kidney disease

37

Leading causes of drug-induced hyperkalemia

Aldosterone antagonist/k-sparing agents and ACEi/ARB

39

___ locally mediate effects of both systemic and locally produced vasoconstrictor hormones

Eicosanoids

40

K secretion in DT is under regulation of

intracellular Mg

42

3 effects of Calcium in HyperKalemia

(1) Less neg resting Vm; (2) Shift upwards and right of Vm x Vmax curve; (3) Reverses depressed conduction

44

Action of Albuterol tx of Hyperkalemia

Activates Na/K --> Na leaving forces K in

46

2 "situations" when PG's play role in preserving renal fxn

True intravascular volume depletion; Effective decrease in renal blood flow

47

Surge in catecholamines is often associated with what electrolyte change

Hypokalemia

48

With no Mg and normal K concentrations, the chemical gradient drives K in which direction?

Outward

49

2 drugs commonly used to tx Hyperkalemia

B2 agonist (Albuterol) and Insulin

50

Insulin stimulates what transporter

Na/H exchange (Na in, H out)

51

PGI2/PGE2 antagonize

local effects (vasoconstriction) of circulating Ang2, Endothelin, Vasopressin, and Catecholamines (that would normally maintain systemic pressure at expense of renal circulation)

52

What aspect of tubular secretion allows for drug-drug interactions

Transporters with overlapping substrae specificities