Pharmacology Flashcards

1
Q

Example of loop diuretics

A

Furosemide

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2
Q

Action of loop diuretics

A

Inhibits Na+K+Cl- cotransporter -> increase ions in the tubules -> reduce hyperosmolarity in intersitium -> reduce in water reabsorption

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3
Q

What must happen for loop diuretics to work

A

Loop diuretics must be filtered out of the glomerulus into the ascending loop of Henle to work

= patients with poor renal function will need higher dose for sufficient effect

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4
Q

Where does loop diuretics act on

A

Ascending limb of loop of Henle

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5
Q

Which NKCC variant does loop diuretics mainly act on

A

NKCC2

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6
Q

When is loop diuretics indicated

A

Heart failure
Resistant hypertension in those with poor renal function

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7
Q

Side effects of loop diuretics

A

Hyponatraemia
Hypokalaemia
Ototoxicity
Hypocalcaemia
Hypomagnesaemia
Gout

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8
Q

loop diuretics can interact with other drugs to cause adverse effects. Which drugs

A

Steroids -> further decrease K+ level

Aminoglycosides -> increase risk of ototoxicity

NSAID -> decrease effect of loop diuretics

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9
Q

Examples of thiazide diuretics

A

Indapamide
Chlortalidone
Hydrochlorothiazide

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10
Q

Action of thiazide diuretics

A

Inhibit Na+ Cl- symporter

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11
Q

Where does thiazide diuretics act on

A

Distal convoluted tubule

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12
Q

Effect of thiazide diuretics

A
  1. Decrease in Na+ reabsorption = more excretion of water
  2. Decrease in Na+ causes increase in Na+ Ca2+ anti porter activity (Ca2+ in Na+ out)-> increase Ca2+ into blood
  3. Potassium loss
  4. Loss of Cl-
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13
Q

Why does thiazide diuretics cause loss of potassium

A

Because less Na+ is absorbed, the body will try to compensate by increasing aldosterone secretion.
Aldosterone increases Na+ reabsorption in exchange for K+ excretion

Hence more K+ excreted

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14
Q

Loss of Cl- due to thiazide diuretics causes

A

Hypochloraemic metabolic alkalosis

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15
Q

Side effects of thiazide diuretics

A

Postural hypotension
Impaired glucose tolerance
Impotence
Hyponatraemia
Hypokalaemia
Hypercalcaemia
Gout

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16
Q

Why can thiazide diuretics be used to prevent recurrence of renal stones

A

Because it causes hypercalcaemia = hypocalciuria (more Ca2+ in blood)

17
Q

Thiazide diuretics is contraindicated in

A

renal failure
may worsen glycaemic control in diabetics
Lithium therapy

18
Q

Types of potassium sparing diuretics

A

Aldosterone antagonist
ENaC (epithelial Na+ channels) inhibitors

19
Q

Example of aldosterone antagonist

A

Spironolactone
Eplerenone

20
Q

Examples of ENaC inhibitors

A

Amiloride
Triamterene

21
Q

Aldosterone antagonists act on

A

Collecting duct - blocks expression of Na+/K+ ATPase (used by aldosterone to increase sodium reabsorption and K+ excretion)

22
Q

ENaC inhibitors act on

23
Q

Potassium sparing diuretics are contraindicated in

A

Addison’s disease
ACEi use

24
Q

Why is potassium sparing diuretics contraindicated in ACEi use

A

ACEi blocks aldosterone hence further decrease K+ secretion which can cause hypokalaemia

25
Examples of osmotic diuretics
Mannitol Isosorbide Glycerine
26
Where do osmotic diuretics act on
PCT Loop of Henle Collecting duct
27
Side effects of osmotic diuretics
Cardiovascular toxicity immediately after injection
28
Osmotic diuretic is contraindicated in
Heart failure
29
Examples of carbonic anhydrase inhibitors
Acetazolamide Dorzolamide
30
Action of carbonic anhydrase inhibitors
Acts on proximal tubules to inhibit bicarbonate reabsorption
31
Effect of carbonic anhydrase inhibitors
Reduces H2CO3 dissociating into HCO3- and H+ -> reduces Na+ reabsorption (because H+ was supposed to be excreted in exchange for reabsorption of Na+)
32
Side effects of carbonic anhydrase inhibitors
Metabolic acidosis (H2CO3 is for acid base balance) Renal stones
33
Which drugs can interact with digoxin to cause toxicity
Loop and thiazide diuretics Spironolactone Amiodarone Verapamil Dilitiazem
34
What happens in digoxin toxicity
Caused by hypokalaemia Digoxin usually competes with K+ to bind to a transporter Hypokalaemia = less competition = enhanced effect of digoxin
35
Symptoms of digoxin toxicity
Unwell Yellow-green vision Anorexia Arrhythmia - bradycardia / heart block Confusion
36
Management of digoxin toxicity
Digibind