2: Drugs acting on the kidney 3 Flashcards Preview

Renal Week 4 2017/18 > 2: Drugs acting on the kidney 3 > Flashcards

Flashcards in 2: Drugs acting on the kidney 3 Deck (37):
1

Which diuretic acts on the proximal tubule to inhibit water reabsorption?

Mannitol

Increases osmolarity of filtrate, so less water enters interstitium by osmosis

2

How is mannitol administered?

IV

3

How does mannitol enter the filtrate?

Filtered by glomeruli

4

How does mannitol decrease

a) water

b) sodium reabsorption?

a) Increases omsolarity of filtrate, so less water wants to pass into the interstitium of the proximal tubules

b) Filtrate is more dilute because there's more water, so Nareabsorption decreases

5

What is mannitol used to treat?

Increased intracranial pressure (cerebral oedema, papilloedema)

Increased intraocular pressure (glaucoma)

6

What are two side effects of mannitol?

Hyponatraemia (inc. blood volume, so diluted)

Hypervolaemia

7

What complication of diabetes causes osmotic diuresis?

Why?

Hyperglycaemia

All the SGLT2 channels are saturated

So less Na+ reabsorbed

So less H2O reabsorbed

Osmotic diuresis

8

What is an example of a carbonic anhydrase inhibitor?

Acetazolamide

9

What is a renal effect of carbonic anhydrase inhibitors?

Stop carbonic anhydrase from converting H+ and HCO3- to carbonic acid

So BICARBONATE is excreted

Causing metabolic acidosis

10

Which eye condition is carbonic anhydrase inhibitors used to treat?

Glaucoma

Inhibits secretion of aqueous humour, reducing intraocular pressure

11

Where is aldosterone secreted from?

What does it do?

Adrenal cortex

Increases Na+ reabsorption and K+ secretion from the distal tubules and collecting ducts

12

Where is ADH secreted from?

What does it do?

Posterior pituitary gland

Increases water reabsorption from collecting ducts

13

Which receptor does ADH bind to?

V2 receptors

14

What is the problem in

a) neurogenic

b) nephrogenic

diabetes insipidus?

a) Lack of ADH secretion from posterior pituitary

b) Resistance of V2 receptors to ADH 

15

What causes nephrogenic diabetes insipidus?

Resistance of V2 receptor to ADH binding

16

Which gene mutates to cause nephrogenic diabetes insipidus?

AVPR2

17

How is neurogenic diabetes insipidus treated?

Desmopressin

18

Why does ethanol cause increased diuresis?

Alcohol inhibits ADH

19

Why does smoking cause reduced diuresis?

Nicotine stimulates ADH

20

What type of receptor is V2?

G-protein coupled receptor

activates adenyl cyclase, then cAMP etc.

21

What change in the apical membrane does activation of V2 receptors cause?

Increased expression of aquaporins

22

Which drugs block V2 receptors?

How do they affect

a) water reabsorption

b) Na+ reabsorption?

Vaptans

Block V2 receptors, so less water is reabsorbed

Same amount of Nais reabsorbed, but smaller BV, so HYPERNATRAEMIA

23

What is an example of a vaptan which is used to treat SIADH and ADPKD?

Tolvaptan

24

Which transporters are found in the proximal tubules and can be targeted by -flozins?

SGLT2

25

Which sodium-glucose transporters are found in the

a) early proximal

b) late proximal

tubules?

a) SGLT2

b) SGLT1

26

How does SGLT work?

Transports glucose INTO cells, against a concentration gradient, by coupling it to Natransport down a concentration gradient

27

Which SGLT channels have

a) a low affinity and high capacity

b) a high affinity and low capacity?

Why is this useful?

a) SGLT2 (proximal)

b) SGLT1 (distal)

If SGLT2 is overloaded with glucose, SGLT1 picks up the rest

28

What renal symptom do SGLT2 inhibitors cause?

Glycosuria

sugary urine

29

Which drugs are used to inhibit SGLT2 inhibitors in the treatment of diabetes?

-flozins

e.g empagliflozin

30

What are the effects on SGLT2 inhibitors?

Reduces HbA1c

Weight loss

31

Given that they cause glycosuria, what is a side effect of SGLT2 inhibitors?

UTI

32

Which acid is metabolised by enzymes to form prostaglandins?

Arachidonic acid

33

Which enzymes metabolise arachidonic acid to form prostaglandins?

COX1 and COX2

34

What do prostaglandins cause in the kidney?

1. Vasodilation of the afferent arteriole (directly)

2. Vasoconstriction of the efferent arteriole (by stimulating RENIN release)

Help to maintain vascular tone of kidneys

35

What property of the kidney do prostaglandins have a large effect on?

GFR

36

How do prostaglandins increase GFR?

1. Prostaglandins DILATE afferent arteriole, increasing RBF

2. Also stimulate secretion of renin, causing Angiotensin II to CONSTRICT efferent arteriole, increasing filtration pressure

37

What may NSAIDs cause in patients with kidney problems?

Why?

Which other drugs may contribute to this?

Acute renal failure

Inhibit COX1 and COX2, inhibiting prostaglandin production

Renal vascular tone disrupted, decreased renal blood flow causes ischaemic nephropathy AKI

ACE inhibitors, ARBs, diuretics