Pharmacology Flashcards

1
Q

List the main drugs that act on the kidney

A
Diuretics
Vasopressin agonists/antagonists
SGLT2 inhibitors
Renal failure drugs
pH-altering drugs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What effect do diuretics have on volume of urine?

A

Increase urine volume by inhibiting reabsorption of salt which causes decreased reabsorption of water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How does oedema arise?

A

Imbalance between rate of formation and absorption of interstitial fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which forces are involved in formation of interstitial fluid?

A
Pc = capillary pressure
πp = capillary oncotic pressure
Pi = interstitial fluid pressure
πI = interstitial fluid oncotic pressure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Disease states that increase/decrease Pc or increase/decrease πp produce oedema

A

Disease states that increase Pc or decrease πp produce oedema

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What (simply) happens in nephrotic syndrome?

A

Disorder of glomerular filtration where plasma protein appears in filtrate, resulting in proteinuria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Once plasma protein is in the urine, it can’t be reabsorbed. True/False?

A

True

Thus voided in urine; urine appears frothy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What effect does the presence of plasma protein in the filtrate have on πp? What is the result of this?

A

Body loses plasma protein in urine so πp decreases; this leads to oedema

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What effect does decreased πp have on blood volume and cardiac output? What is the result of this?

A

Decreased πp causes decreased blood volume and cardiac output, activating RAAS to cause sodium and water retention

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What effect does sodium and water retention have on Pc and πp? What is the result of this?

A

Pc increases and πp decreases, causing oedema

when this happens in nephrotic syndrome, you ultimately get worsening oedema

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

List the major sites of diuretic action in the nephron

A

Proximal convoluted tubule
Ascending limb of loop of Henle
Distal convoluted tubule
Collecting tubule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which class of diuretic works in the proximal convoluted tubule? How does it work?

A

Carbonic anhydrase inhibitor

Blocks production of H+, thus inhibiting Na-H+ exchanger (H+ drive sodium reabsorption)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which class of diuretic works in the ascending limb of loop of Henle? How does it work?

A

Loop diuretic

Blocks Na-K-2Cl triple cotransporter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which class of diuretic works in the distal convoluted tubule? How does it work?

A

Thiazide diuretic

Blocks Na-Cl cotransporter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which class of diuretic works in the collecting tubule? How does it work?

A

Potassium-sparing diuretic

Blocks Na-K antiporter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Diuretics must be in the filtrate to reach site of action. Why?

A

Site of action is the apical membrane (near the lumen)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

List the ways diuretic can enter the filtrate

A

Glomerular filtration (if not bound to plasma protein)
Secretion via transport processes in proximal tubule
Organic anion transporter (OAT)
Organic cation transporter (OCT)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which type of drug - acid or alkali - is transported by organic anion transporter (OAT)?

A

Acidic drugs e.g. thiazide, loop diuretics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Which type of drug - acid or alkali - is transported by organic cation transporter (OCT)?

A

Basic drugs e.g. triamterene, amiloride

20
Q

How do acidic drugs reach the lumen of the tubule?

A

Enter cell via OAT on basolateral membrane in exchange for alpha-ketoglutarate
Exit cell/enter lumen via MRP2 or via OAT

21
Q

How do basic drugs reach the lumen of the tubule?

A

Enter cell via OCT on basolateral membrane

Exit cell/enter lumen via MRP1 or OC-H+ antiporter

22
Q

What competes with thiazide diuretic for the OAT? What is the consequence of this?

A

Uric acid competes with thiazide diuretic for the OAT

Predisposes to gout

23
Q

Name the main loop diuretics

A

Furosemide

Bumetanide

24
Q

Loop diuretics inhibit the Na-K-Cl triple cotransporter by binding the Cl site. This increases the load of Na in the distal tubules - what effect does this have on K, Ca and Mg levels?

A

Less K, Mg and Ca reabsorbed, resulting in hypokalaemia, hypocalcaemia, hypomagnesia

25
List clinical conditions where loop diuretics are used
Acute pulmonary oedema Chronic heart/kidney failure Nephrotic syndrome
26
Name the main thiazide diuretics
Bendroflumethiazide | Hydrochlorothiazide
27
Thiazide diuretics block the Na-Cl cotransporter by binding the Cl site. This increases Na delivered to the collecting tubule - what effect does this have on K and Cl levels?
Less K absorption, resulting in hypokalaemia | Interestingly, for no solid reason, increased Ca absorption
28
List clinical conditions where thiazide diuretics are used
Mild heart failure Hypertension Renal stone disease
29
Name the main potassium-sparing diuretics
Amiloride Triamterene Spironolactone Epleronone
30
How do amiloride and triamterene work?
Block apical Na channel to decrease Na reabsorption, ultimately reduce K excretion
31
How do spironolactone and epleronone work?
Block aldosterone receptor to decrease Na reabsorption, ultimately reduce K excretion
32
Potassium-sparing diuretics are usually used alone. True/False?
False Usually used in conjunction with loop/thiazide where there is hypokalaema Used alone, can cause hyperkalaemia
33
Name an osmotic diuretic
Mannitol
34
How do osmotic diuretics work?
Become trapped in filtrate (cannot be reabsorbed) and exert osmotic pressure to retain water, which in turn retains sodium due to dilution Net effect: decrease water and sodium reabsorption
35
What is the main indication for using osmotic diuretic?
Prevent acute hypovolaemic renal failure
36
Name a carbonic anhydrase inhibitor
Acetazolamide
37
What is the effect of carbonic anhydrase inhibitor?
Increase excretion of HCO3, Na, K and H20 (alkaline diuresis), resulting in metabolic acidosis
38
How do aquaretics work?
Block vasopressin receptors to cause excretion of water without Na loss, resulting in hypernatraemia
39
Name some aquaretics
Conivaptan (V1a, V2) | Tolvaptan (V2)
40
Where do SGLT2 inhibitors act?
Block SGLT2 in the proximal tubule to prevent glucose reabsorption
41
SGLT1 is present in the intestine only, SGLT2 in the kidney only. True/False?
False SGLT1 = intestine + kidney SGLT2 = kidney only
42
SGLT2 have low/high affinity for glucose; SGLT1 have low/high affinity for glucose
SGLT2 have low affinity for glucose; SGLT1 have high affinity for glucose
43
Name some SGLT2 inhibitors
Dapagliflozin | Canagliflozin
44
Which enzymes catalyse the formation of prostaglandins?
Cyclo-oxygenases | COX
45
State the major prostaglandins synthesised by the kidney
PGE2 (medulla) | PGI2 (glomeruli)
46
What is the effect of prostaglandins on vasculature and GFR?
Vasodilation of afferent arteriole | Increase GFR by constricting efferent arteriole
47
How might NSAIDs cause acute renal failure?
Inhibit COX, thus inhibit prostaglandin formation, so GFR decreases