Cardiac Pharmacology: Drugs for Heart Failure (2)

Question 1

CLASS: IA
MECHANISM OF ACTION:
Binds to activated sodium channels and blocks the flow of sodium ions into the cardiac myocyte (prolongs action potential)
CLINICAL USE:
Atrial fibrillation
Atrial flutter
Ventricular tachycardia

Answer 1

EXAMPLES:
Quinidine
Procainamide
Disopyramide

Question 2

CLASS: IB
MECHANISM OF ACTION:
Bind to both activated and inactivated sodium channels and blocks the flow of sodium ions in the cardiac myocyte (Shortens action potential)
CLINICAL USE:
Post-ischemic arrythmia
Ventricular fibrillation
Ventricular tachycardia

Answer 2

EXAMPLES:
Lidocaine
Tocainide
Mexiletine

Question 3

CLASS: IC
MECHANISM OF ACTION:
Binds to activated sodium channels and blocks the flow of sodium ions into the cardiac myocyte (No effect on action potential)
CLINICAL USE:
Treatment of severe refractory

Answer 3

EXAMPLES:
Flecainide
Encainide
Propafenone

Question 4

CLASS: II
MECHANISM OF ACTION:
Blocks beta-adrenergic receptors
CLINICAL USE:
Numerous

Answer 4

EXAMPLES:
Propanolol
Metoprolol

Question 5

CLASS: III
MECHANISM OF ACTION:
Binds to potassium channels and blocks the flow of K in the myocyte (Prolongs action potential)
CLINICAL USE:
Atrial and ventricular arrythmias

Answer 5

EXAMPLES:
Sotalol
Ibutilide
Bretylium
Amiodarone (has Class I-IV anti-arrythmic actions)

Question 6

CLASS: IV
MECHANISM OF ACTION:
Blocks voltage-gated calcium channels thereby blocking the flow of calcium into the cell
CLINICAL USE:
Supraventricular tachycardia
Rate reduction in patients with atrial fibrillation

Answer 6

EXAMPLES:
Verapamil
Diltiazem