Heart failure drugs

Question 1

What is the mechanism of action of digitoxin

Answer 1

Na/K+ pump inhibitor

Question 2

What are the consequential actions of Digitoxin

Answer 2

Increased force of contraction
Increased excitability
Increased A-V conduction
Decreased heart rate

Question 3

What is the effective range (dose) of Digitoxin

Answer 3

1.0-2.5ng/ml

Question 4

What is the toxic dose of Digitoxin

Answer 4

> 1.5ng/ml

Question 5

What are the side effects of Digitoxin

Answer 5

GI:
-anorexia 
-abdominal pain 
-vominting and diarrhoea 
Arrythmias:
-Premature ventricular contractions 
-Atrial tachycardias 
-Atrioventircualr dissociation

Question 6

Where is Digitoxin extracted from

Answer 6

foxglove plant (Digitalis)

Question 7

What is the use of Digitalis (Digitoxin)

Answer 7

Clearly indicated in failure when atrial flutter/ fibrillation is present

Question 8

Describe the half life and administration of Digitoxin

Answer 8

The long half life means that careful titration of patient dose is needed

Question 9

Give examples of receptor sympathomimetics used to treat heart failure

Answer 9

Dobutamine

Dopamine

Question 10

what is the mechanism of action of Dobutamine and Dopamine

Answer 10

stimulate beta-1 receptors

Question 11

Give an example of a nitrate used to treat angina

Answer 11

GTN (glycerol trinitrate)

Question 12

what is the mechanism of action of GTN (glycerol trinitrate)

Answer 12

Increase the amount of NO
Mo causes relaxation of vascular smooth muscle in arteries and veins
This decreases preload and afterload

Question 13

What are the side effects of GTN (glycerol trinitrate)

Answer 13

heachache

dizziness

Question 14

Give an example of a loop agent diuretic used to treat heart failure

Answer 14

Furosemide

Question 15

What is the mechanism of action of furosemide

Answer 15

inhibits reabsorption of 30% of the filtered Na+ in the kidney

Question 16

What is furosemide used for

Answer 16

Pulmonary and refractory oedema

Kidney failure

Question 17

What are the side effecs of furosemide

Answer 17

Ototoxicity
Hypovolemia
Hypokalemia
Hypomagnesia

Question 18

Give an example of a thiazide diuretic

Answer 18

Hydrochlorothiazide

Question 19

What is the mechanism of action of Hydrochlorothiazide

Answer 19

Mild diuretic effect
Inhibits reabsorption of <10% of filtered Na+
It mainly acts on the distal convoluted tubule
Direct vasodilator action on smooth muscle

Question 20

When is Hydrochlorothiazide used clinically

Answer 20

Hypertensives

Question 21

What are the side effects of Hydrochlorothiazide

Answer 21

Potassium loss

Hypotension

Question 22

Give an example of a K+ sparing diuretic

Answer 22

Amiloride

Spirononlactone

Question 23

What is the mechanism of action of Amiloride and

Spirononlactone

Answer 23

Weak diuretic effect

inhibits reabsorption of <5% of filtered Na+

Question 24

What are Amiloride and Spirononlactone useful for

Answer 24

controlling K+ loss

Question 25

What are the side effects of Amiloride and | Spirononlactone

Answer 25

Hyperkalemia Spirononlactone has oestrogen like effects

Question 26

Give examples of ACE inhibitors used to treat heart failure

Answer 26

Captopril | Analpril

Question 27

What is the mechanism of action of the ACE inhibitors

Answer 27

Inhibit production of angiotensin II and thus: - inhibit aldosterone production - Cause vasodilation as inhibit bradykinin breakdown

Question 28

What are ACE inhibitors useful for

Answer 28

controlling K+ loss | Hypertension

Question 29

What are the side effects of ACE inhibitors

Answer 29

Cough Hypotension Hyperkalemia

Question 30

Give an example of an angiotensin II receptor blocker used to treat heart failure

Answer 30

Losartan

Question 31

What is the mechanism of action of losartan

Answer 31

angiotensin II receptor blocker it reduces BP Does not effect bradykinin so no cough

Question 32

What are the side effects of losartan

Answer 32

Less vasodilation than ACE inhibitors | Birth defects