ANTI-ARRHYTHMIC DRUGS

Question 1

The ultimate goal of antiarrhythmic drug therapy is to

Answer 1

Restore normal sinus rhythm and conduction
Prevent more serious and possibly lethal arrhythmias from occurring.

Question 2

Antiarrhythmic drugs are used to

Answer 2

decrease conduction velocity
change the duration of the effective refractory period (ERP)
suppress abnormal automaticity

Question 3

classify antiarrhythmic drugs according to Vaughan William

Answer 3

checknote

Question 4

Class 1A Drugs

Answer 4

Quinidine
Procainamide

Question 5

Class IA Drugs Uses

Answer 5

Supraventricular and ventricular arrhythmias

Question 6

Class IA Drugs Toxicity

Answer 6

quinidine-
AV block
Torsade’s de pointes arrhythmia
↑digoxin concentration
Ventricular tachycardia

procainamide-
Asystole or ventricular arrhythmia
Hypersensitivity : fever, agranulocytosis

Question 7

Class IB Drugs

Answer 7

Lidocaine, Mexiletine

Question 8

Class IC Drugs

Answer 8

Propafenone, Flecaimide

Question 9

Class II ANTIARRHYTHMIC DRUGS uses

Answer 9

(β-adrenergic blockers)
Treatment of increased sympathetic activity-induced arrhythmias such as stress- and exercise-induced arrhythmias

Question 10

Class III ANTIARRHYTHMIC DRUGS

Answer 10

Amiodarone, Sotalol

Question 11

Class III ANTIARRHYTHMIC DRUGS Uses

Answer 11

Ventricular arrhythmias, especially ventricular fibrillation or tachycardia
Supra-ventricular tachycardia

Question 12

Class IV ANTIARRHYTHMIC DRUGS examples

Answer 12

: verapamil & diltiazem
used because they act on the heart only and not on blood vessels.
Dihydropyridine family are not used because they only act on blood vessels

Question 13

DRUGS TO TREAT HEART FALIURE classification

Answer 13

inotropic drugs
diuretics
aldosterone antagonist
beta blockers
vasodilators

Question 14

Inotropic drugs
examples

Answer 14

Cardiac glycosides:
Digoxin, digitoxin

Sympathomimetic amines:
Dopamine , dobutamine

Phosphodiesterase inhibitors:
Amrinone , milrinone

Question 15

Vasodilators examples

Answer 15

Arteriolar: hydralazine , minoxidil,

Venodilators: nitrates

Arteriolar and venodilators: ACE inhibitors, ARB

Question 16

diuretics examples

Answer 16

Loop diuretics: furosemide, torsemide
Thiazide diuretics: hydrochlorthiazide
K+ Sparing diuretics:
Spironolactone
Amiloride

Question 17

Beta Blockers
(cardioselective)

Answer 17

Metoprolol, atenolol

Question 18

Digoxin –Mechanism of action

Answer 18

Induces an increase in intracellular sodium that will drive an influx of calcium in the heart and cause an increase in contractility
Also inhibits the AV Node

Question 19

Uses of digoxin

Answer 19

Congestive heart failure
Cardiac arrhythmias

Question 20

Adverse effects of digoxin

Answer 20

GIT: Nausea & vomiting (first to appear)
CNS: Restlessness, Disorientation
Endocrine: Gynaecomastia

Cardiac
Bradycardia (first cardiac toxic sign)
arrhythmia

Question 21

Treatment of toxicity

Answer 21

Stop digitalis
Digoxin antibodies
Oral or parenteral potassium supplements
For ventricular arrhythmias- Lidocaine IV
For supraventricular arrhythmia-Propranolol IV or orally
For AV block and bradycardia- Atropine IM

Question 22

DOPAMINE

Answer 22

An endogenous catecholamine
Induces intrarenal vasodilatation, inhibition of renal tubular sodium reabsorption
Direct stimulation of peripheral dopaminergic receptors DA1 and DA2
In higher doses may affect the Beta-1 and alpha receptors promoting tachycardia and PVR
Hence, the preference of the synthetic amine, dobutamine, which is more beta-1 specific

Question 23

Dobutamine

Answer 23

Synthetic catecholamine
Stimulates beta1, beta 2 and alpha-1 receptors
Has no effect on dopamine and alpha -2 receptors
Dobutamine is preferred when there is a need to improve low cardiac output.

Question 24

DRUGS TO TREAT ANGINA PECTORIS

Answer 24

ORGANIC NITRATES: Glyceryl trinitrate (Nitroglycerin), Isosorbide dinitrate, etc

•BETA BLOCKERS: Propranolol, Atenolol, Metroprolol, Carvedilol, etc

• CALCIUM ANTAGONIST: Nifedipine, Diltiazem, Verapamil