Anti-arrhythmic drugs, or rhythm control medications, are prescribed to actually stop your atrial fibrillation completely. Their purpose is to get your heart to beat regularly. That’s a big difference from rate control medications that merely slow your heart rate down, while allowing you to stay in afib.
Unfortunately, these drugs aren’t always effective and can have serious side effects. In addition, patients are prone to develop a resistance to them. Up to 50% of patients experience a recurrence of afib after 1-year of antiarrhythmic treatment, and up-to 85% experience a recurrence after 2-years.source
When you first start taking rhythm control drugs you may have to spend time in the hospital for a few days to make sure that you don’t have any adverse reactions to them. Some of the side effects of these drugs include:
- Skin discoloration
- Pulmonary fibrosis (scaring of the lungs)
- Impaired liver function
Classes of Anti-Arrhythmic Drugs
Rhythm control medications and rate control medications fall into one of five classes – Class I, II, III, IV and V – based on how they work. Listed below are the five classes and the drugs in each class.
The drug names are listed by generic name followed by the brand names in parentheses. The drugs in bold are the most common rhythm control medications (again, drugs meant to stop your afib and get your heart to beat regularly).
Class I – Sodium Channel Blockers
These decrease the speed of electrical conduction in the heart muscle. The drugs in this class are divided into three groups – IA, IB, and IC.
- IA Drugs: quinidine (Quinaglute, Quinidine Glaconate, Quinidex), procainamide (Procan SR, Promine, Pronestyl, Procanbid), disopyramide (Norpace)
- IB Drugs: lidocaine, phenytoin, mexiletine, tocainide
- IC Drugs: flecainide (Tambocor), propafenone (Rhythmol and the newer version Rhythmol SR), moricizine, encainide
Class II – Beta Blockers
These slow down conduction through the heart and make the AV node less sensitive to atrial fibrillation impulses. The drugs in this class include:
- propranolol (Inderal)
- esmolol (Brevibloc)
- metoprolol (Lopressor, Toprol-XL)
- atenolol (Tenormin)
- carvedilol (Coreg)
- nebivolol (Bystolic)
Class III – Potassium Channel Blockers
These slow nerve impulses in the heart. The drugs in this class include:
- amiodarone (Cordarone, Pacerone)
- sotalol (Betapace)
- ibutilide (Corvert)
- dofetilide (Tikosyn)
- dronedarone (Multaq)
Class IV – Calcium Channel Blockers
These prevent or slow the flow of calcium into the heart, which impedes muscle cell contraction. The drugs in this class include:
- verapamil (Calan, Isoptin)
- diltiazem (Dilt, Cardizem, Tilazem, Cartia XT)
Class V – Unknown
The drugs in this class work by other or unknown mechanisms. They include:
- magnesium sulfate
The PIP Treatment Approach (Pill-in-the-Pocket)
Anti-arrhythmic drugs are either prescribed for you to take daily or “as needed.” The latter option is called the pill-in-the-pocket treatment approach. The idea is you only take your medication when you have an atrial fibrillation episode. You don’t take it everyday. If you have occasional episodes of afib, this is a treatment approach many doctors and patients will consider.
Another treatment approach is to take a low daily dose of a rhythm control medication and then take a higher dose during an atrial fibrillation episode.
If your doctor prescribes anti-arrhythmic drugs, he/she will work with you to determine which treatment option is best for you. You may have to take these drugs daily or only when needed (PIP treatment).