Cardiovascular Pharmacology (Drugs)

Question 1

What substances can mimic the effect of sympathetic stimulation of the heart?

Answer 1

• Cholera toxin: Stimulates β₁-associated G-protein
• Forskolin: Adenylyl cyclase agonist

Question 2

What are Vaughan Williams’ classifications of antidysrhythmic drugs?

Answer 2

1. Class I: Voltage-gated Na⁺ channel blockers
2. Class II: Sympathetic antagonists (β-blockers)
3. Class III: Prolonge action potential
4. Class IV: Ca²⁺ channel blockers

Question 3

What are the subdivisions of class I drugs?

Answer 3

1. Class Ia: Intermediate association/dissociation time. Displays both Ib and Ic properties.
2. Class Ib: Fast association/dissociation time. Binds to Na⁺ channels during depolarisation phase of AP and prevents premature activation.
3. Class Ic: Slow association/dissociation time. Binds to Na⁺ channel throughout AP. Has no effects on AP waveform but slows down rate of AP conduction.

Question 4

What are examples of Ia antidysrhythmic drugs?

Answer 4

1. Quinidine
2. Procainamide

Question 5

What are examples of Ib antidysrhythmic drugs?

Answer 5

Lidocaine

Question 6

What are examples of Ic antidysrhythmic drugs?

Answer 6

1. Flecainide
2. encainide

Question 7

What are examples of class II antidysrhythmic drugs?

Answer 7

1. Propanolol
2. Atenolol
3. Metoprolol

Question 8

What are examples of class III antidysthythmic drugs?

Answer 8

Amiodarone

Question 9

What are examples of class IV antidysrhythmic drugs?

Answer 9

1. Verapamil

Question 10

What are the different types of drugs used to treat heart failure?

Answer 10

1. Cardiac glycosides
2. β agonists
3. β antagonists
4. Inodilators
5. ACE inhibitors
6. Calcium sensitisers

Question 11

What are examples of cardiac glycosides?

Answer 11

1. Digoxin
2. Ouabain

Question 12

What are examples of β₁ agonists used in heart failure?

Answer 12

Dobutamine

Question 13

What are the clinical uses of β₁ agonists in heart failure?

Answer 13

1. Shock
2. Heart failure in absence of hypertension

Question 14

What are examples of β-antagonists in heart failure?

Answer 14

1. Bisoprolol
2. Carvedilol

Question 15

What are inodilators?

Answer 15

Phosphodiesterase inhibitors

Question 16

What are the types of phosphodiesterases?

Answer 16

1. Type I: Ca²⁺/calmodulin-dependent
2. Type II: cGMP-stimulated
3. Type III: cGMP-inhibited
4. Type IV: cAMP-specific
5. Type V: cGMP-specific

Question 17

What are examples of type III phosphodiesterase-specific inodilators?

Answer 17

Milrinone

Question 18

What are examples of type V phosphodiesterase-specific inodilators?

Answer 18

1. Dipyridamole
2. Sildenafil (viagra)

Question 19

Which type of PDE is most widely targeted to treat heart failure?

Answer 19

Class III

Question 20

What is the mechanism of methylxanthines in heart failure?

Answer 20

1. Inhibition of PDE causes increased [cAMP] and sympathomimetic effects on heart.
2. Inhibition of adenosine A_1/2 receptors causes release of intracellular Ca²⁺.

Question 21

What is an example of a Ca²⁺ sensitiser?

Answer 21

Levosimendan

Question 22

What are the classes calcium channel antagonists?

Answer 22

1. Dihydropyridines
2. Phenylalkylamines
3. Benzothiazepines

Question 23

What are examples of dihydropyridines?

Answer 23

Nifedipine

Question 24

What are examples of phenylalkylamines?

Answer 24

Verapamil

Question 25

What are examples of benzothiazepines?

Answer 25

Diltiazem