What are the most common antiarrhythmic drugs?
So. what are the most common antiarrhythmic drugs? Let’s start with the basics
What are antiarrhythmic drugs?
Antiarrhythmics are medications that prevent and treat a heart rhythm that is too fast or irregular also known as arrhythmias. Arrhythmia involves a problem with your heart’s electrical system. Your heart may beat too quickly, too slowly or erratically (irregularly). Antiarrhythmics treat abnormal heart rhythms including atrial fibrillation, atrial flutter, ventricular tachycardia or ventricular fibrillation.
How do antiarrhythmics work?
In general, antiarrhythmics reset your heart to a normal rhythm or prevent episodes of arrhythmia. They act on the heart’s various electrical channels (see below) to:
- Stop an irregular, extra electrical impulse in your heart.
- Prevent abnormally fast electrical impulses from traveling along heart tissues.
There are several classes of antiarrhythmics. Each class works in a different way, depending on the type of arrhythmia and its cause.
Most arrhythmia medications are taken by mouth over a long period of time for lasting treatment. Some are delivered intravenously (injected into the bloodstream) for patients who are unstable or cannot take oral medications.
What are the treatment options for abnormal heart rhythms?
There are several types of arrhythmia treatments, including:
- Medication
- Lifestyle changes
- Implanted medical devices (e.g. a pacemaker)
- Surgery (e.g. cardiac ablation).
Your doctor will recommend treatment depending on the type of arrhythmia you have and how serious it is. They may recommend antiarrhythmic medications if arrhythmia:
- Doesn’t respond to lifestyle changes.
- Interferes with your daily activities.
- Might cause a life-threatening complication, such as heart failure, cardiac arrest or stroke.
What are the 4 classes of antiarrhythmic medication?
There are four classes of antiarrhythmics, based on the Vaughan-Williams (VW) classification system:
- Class I. Sodium channel blockers. These drugs prevent sodium from getting through cell membranes. This can slow electrical impulses in the heart muscle. Examples include disopyramide, flecainide, mexiletine, propafenone and quinidine.
- Class II. Beta blockers. These drugs slow down the heart rate. Examples include acebutolol, atenolol, bisoprolol, metoprolol, nadolol and propranolol.
- Class III. Potassium channel blockers. These drugs prevent potassium from getting through cell membranes. This slows down electrical impulses in the heart’s cells. Examples include amiodarone, bretylium, dofetilide, dronedarone, ibutilide and sotalol.
- Class IV. Nondihydropyridine calcium channel blockers. These drugs block calcium channels in heart muscle. This can decrease heart rate and contractions. Examples include diltiazem and verapamil.
Other antiarrhythmic drugs not included in the VW classification system include:
Adenosine. This medication can block or slow down electrical impulses at the atrioventricular node (AVN), between the upper and lower chambers of the heart.
Digoxin. This drug slows the heart rate and make it contracts more strongly.
Arrhythmia treatment also may involve other medications that are not antiarrhythmics, such as anticoagulants (blood thinners).
How effective are antiarrhythmic drugs?
Antiarrhythmics are often very effective. But it may take several tries to find the medication and dose that works best for you depending on efficacy and tolerability.
Summary
We have described what are the most common antiarrhythmic drugs. We hope it has been helpful.
Other resource
This is a good review article: King, 2023.
