These are medications designed to prevent and treat heart rhythms that are too fast or irregular.
How They Work
Arrhythmias are caused by problems in the heart's electrical system. Antiarrhythmics target the specific "channels" (Sodium, Potassium, Calcium) in your heart cells to:
- Stop extra electrical impulses.
- Prevent impulses from traveling too fast.
- Slow down the heart rate.
The 4 Classes of Medication
Doctors classify these drugs using the Vaughan-Williams System.
Class I: Sodium Channel Blockers
Action: Slows electrical impulses in the heart muscle.
Examples: Flecainide, Propafenone, Quinidine.
Class II: Beta Blockers
Action: Slows heart rate by blocking adrenaline.
Examples: Metoprolol, Atenolol, Bisoprolol.
Class III: Potassium Channel Blockers
Action: Slows electrical impulses in all heart cells.
Examples: Amiodarone, Sotalol, Dofetilide.
Class IV: Calcium Channel Blockers
Action: Decreases heart rate and contractions.
Examples: Diltiazem, Verapamil.
Note: Other drugs like Digoxin and Adenosine are also used but fall outside this classification system.
Benefits
These drugs effectively relieve symptoms such as:
- Chest pain.
- Dizziness or fainting.
- Heart palpitations.
- Shortness of breath.
Common Side Effects
- Dizziness
- Nausea
- Headache
- Constipation
- Sun sensitivity
- Fluid swelling
- Vision changes
- Ringing ears
Important Safety Warnings
1. The "Pro-Arrhythmia" Risk
Ironically, arrhythmia medications can sometimes cause new arrhythmias. You must be monitored carefully by your doctor.
2. Drug Interactions
These drugs interact with many things, including herbal supplements and over-the-counter meds. Always give your doctor a full list of what you take.
3. Overdose Signs
Seek emergency help if you experience confusion, seizures, inability to wake up, or extreme difficulty breathing.
Duration: Most antiarrhythmics are long-term medications. Never stop taking them or change the dose without talking to your provider.