Heart Failure

Question 1

Ouabain

Answer 1

Cardiac glycoside. Too potent for therapeutic use.
Blocks cardiac NaKATPase. This reduces the extracellular sodium gradient for calcium export, increasing intracellular calcium levels.
Dangerously potentiated by calcium loss so only use potassium sparing diuretics alongside eg. Spironolactone
May combine with ACE inhibitors

Question 2

Enalapril

Answer 2

ACE inhibitor prodrug. Converted in liver to enalaprilat.
Prevents activation of ATI in the lungs to ATII.
Reduces thirst, increases nateuresis, lowering blood volume and pressure and reducing the load on the heart - lowering oedema.

Question 3

Captopril

Answer 3

ACE inhibitor.
Prevents activation of ATI in the lungs to ATII.
Reduces thirst, increases nateuresis, lowering blood volume and pressure and reducing the load on the heart - lowering oedema.

Question 4

Losartan

Answer 4

Non peptide angiotensin receptor blocker
Blocks AT1
High benefit in cardiac failure associated with high renin levels
Decrease pre load and after load
Reduces aldosterone, avoiding hypokalaemia

Question 5

Dobutamine

Answer 5

Beta 1 receptor agonist
Greater ionotropic effects than chronotropic
IV administration
Side effects include increasing oxygen demand, increasing HR and hypertension

Question 6

Bisoprolol

Answer 6

Beta 1 blocker
Dampens the physiological sympathetic response which further damages the heart
There is a physiological receptor desensitisation, particular B1
Potential for overinhibition

Question 7

Milrinone

Answer 7

Inodilator
PDE III inhibitor
Short term treatment of heart failure
Prevents cAMP/cGMP breakdown, potentiating the effect of beta agonists

Question 8

Digoxin

Answer 8

Cardiac glycoside.
Blocks cardiac NaKATPase. This reduces the extracellular sodium gradient for calcium export, increasing intracellular calcium levels.
Dangerously potentiated by calcium loss so only use potassium sparing diuretics alongside eg. Spironolactone
May combine with ACE inhibitors

Question 9

Pimobendan

Answer 9

Calcium sensitiser, inodilator
Blocks PDE III
Used in canine cardiomyopathies

Question 10

Levisomendan

Answer 10

Calcium sensitiser/inodilator
Inhibits PDE III
Human use outside UK