Commonly Used Brand Names in the United States
Betapace/Betapace AF (sotalol)
Calan/Calan SR (verapamil)
Coreg/Coreg CR (carvedilol)
Dilacor XR (diltiazem)
Diltia XT (diltiazem)
Inderal/Inderal LA (propranolol)
Innopran XL (propranolol)
Lopressor/Lopressor HCT (metoprolol)
Norpace/Norpace CR (disopyramide)
Quinaglute Dura-tabs (quinidine)
Quinidex Extentabs (quinidine)
Toprol XL (metoprolol)
Verelan/Verelan PM (verapamil)
Therapeutic Uses of Antiarrhythmics
Antiarrhythmics are used to treat:
• Arrhythmias (heart rhythm disorders)
• Symptoms associated with arrhythmias
o heart palpitations
o irregular heartbeats
o fast heartbeats (tachycardia)
o chest pain (angina)
o high blood pressure (hypertension)
o shortness of breath
How Antiarrhythmics Work
Antiarrhythmic medicines slow the electrical impulses in the heart so that it can resume its normal rhythm and conduction patterns. The four different ways these medicines work are:
• Class I antiarrhythmic medicines are sodium channel blockers, which slow electrical conduction in the heart.
• Class II antiarrhythmic medicines are beta blockers, which block the impulses that may cause the irregular rhythm and interfere with hormonal influences (such as adrenaline) on the heart’s cells. This type of antiarrhythmic also reduces blood pressure and heart rate.
• Class III antiarrhythmic medicines are potassium channel blockers, which slow the electrical impulses in the heart.
• Class IV antiarrhythmic medicines are calcium channel blockers, which work like class II medicines.
Because each kind of antiarrhythmic medicine works in a slightly different way, no one medicine is used to treat every kind of arrhythmia. An antiarrhythmic medicine can sometimes cause more arrhythmias or make an arrhythmia worse (called proarrhythmia). A patient and his or her doctor must work closely together with good communication to try out the different kinds of antiarrhythmic medicines and determine which medicine works best. This process may include additional monitoring or testing with a Holter monitor or electrophysiology studies (EPS).
The information in this section is meant to provide a brief description of these medicines. It does not cover all of the possible uses, warnings, dosages, side effects, or interactions with other medicines and vitamin or herbal supplements. This information should not be used as medical advice for individual problems.
Texas Heart Institute www.texasheartinstitute.com/HIC/Topics/Meds/antiarrh.cfm
American Heart Association www.americanheart.org/presenter.jhtml?identifier=153
Updated December 2009