CPRS 71: Positive Inotropic Drugs

Question 1

What are positive inotropic drugs

Answer 1

Drugs to increase the heart contraction force

Question 2

Name 2 Beta Adrenergic Receptor Stimulants

Answer 2

Dobutamine

Dopamine

Question 3

How does Beta Adrenergic Receptor Stimulants work

Answer 3

Increase cAMP level
PKA Activation
Increase calcium entry
Increase Calcium ions in cells for contraction

Question 4

Dobutamine (Negative enantiomer) is an agonist for ________ receptors. (Positive enantiomer) is an agonist for _________ receptors.

Answer 4

Alpha

Alpha

Question 5

Why is dobutamine only a mild vasodilator

Answer 5

Effect of negative enantiomer is offset by positive enantiomer plus beta 2 receptor stimulation.

Question 6

Dobutamine is a __________ beta receptor stimulant.

Answer 6

non-selective

Question 7

At low doses, dopamine will activate ______ receptors. At intermediate doses, dopamine will activate _______ receptors. At high doses, dopamine will activate _________ receptors.

Answer 7

Beta 2
Beta 1
Alpha

Question 8

At high doses, dopamine will activate alpha receptors, this will lead to _____________. This increases the _______ of the heart and leads to __________.

Answer 8

Vasoconstriction
Afterload
Decrease in cardiac output

Question 9

What are the adverse effects of beta adrenergic receptor stimulants

Answer 9

Pro-angina (Increase heart rate, B1)

Pro-arrhythmic (Increase Ca concentration, B2)

Question 10

What is the advantage of Beta adrenergic receptor stimulants

Answer 10

Short duration of action

Question 11

Name 2 PDE Inhibitors

Answer 11

Milrinone

Enoximone

Question 12

What’s the mechanism of PDE inhibtiors

Answer 12

Inhibit PDE
Reduce Breakdown of cAMP to AMP
Increase level of cAMP
Increase PKA level 
Increase Ca2+ ions, increase contraction

Question 13

Name the 2 adverse effects of PDE inhibitors

Answer 13

Pro-arrhythmic (Increase Ca 2+ concentration)

Hypotension

Question 14

Name 1 advantage of PDE inhibitors

Answer 14

Vasodilation

Question 15

Name 1 Cardiac Glycoside

Answer 15

Digoxin

Question 16

What is the mechanism of Cardiac Glycosides- Digoxin

Answer 16

Inhibit the Na/K ATPase, less Na+ pumped out
Shift Na/Ca exchanger to pump out Na and pump Ca in
Increase Ca storage for muscle contraction

Question 17

Name the 2 adverse effects of Cardiac Glycosides

Answer 17

Pro-arrhythmic (increase Ca2+)

Narrow Safety Margin- Not the 1st line therapy

Question 18

What is the major limitation of Cardiac Glycosides

Answer 18

Effect opposed by increase potassium level

Question 19

Name 1 Calcium Sensitizer

Answer 19

Levosimendan

Question 20

How does Calcium Sensitizer- Levosimendan, work?

Answer 20

Stabilize the binding between Troponin C and Calcium ions.

Increases the contractility of cardiac muscle without increase in Calcium concentration.

Question 21

What is the composition of LCZ696

Answer 21

Valsartan 50%

Sacubitril 50%

Question 22

What is LCZ696 used to treat

Answer 22

Chronic Heart Failure

Question 23

What is the function of Valsartan

Answer 23

Angiotensin receptor inhibitor

Prevent the rise in blood pressure

Question 24

What is the function of Sacubitril

Answer 24

Neprilysin Inhibitor

Question 25

What is the function of Neprilysin Inhibitor

Answer 25

Reduce the breakdown of natriuretic peptides, bradykinin and substance P Also reduce breakdown of Angiotensin II

Question 26

What will the accumulation of Natriuretic Peptides lead to

Answer 26

Diuresis Natriuresis Vasodilatation

Question 27

What will the accumulation of Bradykinin and Substance P lead to

Answer 27

Vasodilation

Question 28

What will the accumulation of Angiotensin II lead to

Answer 28

Vasoconstriction | That's why need Valsartan as Angiotensin Receptor Blocker

Question 29

What is the precaution of using LCZ696

Answer 29

Not to use it in combination with ACE inhibitor

Question 30

Name 2 Adverse Effects of LCZ696

Answer 30

``` Increase hypotension (vasodilation) Increase angioedema (Increase bradykinin and Substance P) ```