Antiarrhythmic
Medications
Antiarrhythmic drug therapy is a treatment option for many
patients with cardiac tachyarrhythmias. Table 1 summarizes the common medications used for the treatment of cardiac arrhythmias.
Table 1. Commons Medications Used in the Treatment of Cardiac Tachyarrhythmias
|
Class
of Medication |
Examples |
Common
Side Effects* |
|
Digitalis
Glycosides |
Digoxin |
None
at therapeutic levels |
|
Beta-Adrenergic
Blocking Drugs |
Atenolol,
Propranolol,
Metoprolol |
Fatigue,
Lethargy |
|
Calcium
Channel Blocking Drugs |
Verapamil,
Diltiazem |
Constipation,
Fatigue |
|
Class
IA Antiarrhythmic Drugs |
Quinidine,
Procainamide, Disopyramide |
Variable.
Rarely, may cause arrhythmias. |
|
Class
IC Antiarrhythmic Drugs |
Flecainide,
Propafenone |
Variable.
Rarely, may cause arrhythmias. |
|
Class
III Antiarrhythmic Drugs |
Sotalol,
Amiodarone, Dofetilide |
Variable.
Amiodarone may cause liver, thyroid, or lung
problems. Rarely, may cause arrhythmias. |
*In all cases, side effects cannot be predicted and are dependent upon individual patient variation.
Calcium blockers
and beta-adrenergic blockers are the most common medications used for
patients with AV nodal reentrant tachycardia, AV reciprocating tachycardia,
and atrial tachycardia because they have mild side effects and may
be very effective. Patients with atrial flutter and atrial fibrillation
often require treatment with class I, II, or III antiarrhythmic drugs
for best control. Patients with potentially life-threatening ventricular
tachyarrhythmias generally are treated with implantable cardioverter-defibrillators
(ICD), although amiodarone or sotalol are often used in conjunction
with the ICD. However, patients with atypical monomorphic ventricular
tachycardia (and structurally normal hearts) may be effectively and
safely treated with these drugs.
Drug efficacy, however,
is highly individualized, with some patients responding very well to
these medications, while other patients may find these medications
completely ineffective. It is rare that a medication is either 100%
effective or 100% ineffective, with most providing partial improvement
in the frequency, severity, and duration of arrhythmia episodes. In
addition, drug therapy of these arrhythmias is a trial and error proposition;
it is not possible to determine ahead of time which medication will
work best in a particular patient. The critical feature of drug therapy
is that it does not cure the tachycardia; at best it only can suppress
the tachyarrhythmia if the medication is taken on a regular basis.
Because an oral medication can take an hour or more to reach significant
levels in your blood after swallowing the pill or tablet, taking the
medication only at the time of onset of the tachycardia is rarely effective
in immediately terminating the arrhythmia. |
