Propafenone is used to treat arrhythmia (irregular heartbeat) and to maintain a normal heart rate. Propafenone is in a class of medications called antiarrhythmics. It works by acting on the heart muscle to improve the heart’s rhythm.

Side Effects Of Propafenone

Propafenone may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • dizziness
  • dry mouth
  • headache
  • nausea
  • vomiting
  • diarrhea
  • constipation
  • loss of appetite
  • unusual taste in the mouth
  • gas
  • tiredness
  • anxiety
  • blurred vision
  • uncontrollable shaking of a part of the body
  • difficulty falling asleep or staying asleep
  • difficulty with coordination

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:

  • difficulty breathing
  • wheezing
  • chest pain
  • new or worsening irregular heartbeat
  • slow, fast, or pounding heartbeat
  • swelling of the hands, feet, ankles, or lower legs
  • sudden, unexplained weight gain
  • fainting
  • skin rash
  • unexplained fever, chills, weakness, or sore throat

Warnings & Precautions

Before taking propafenone:

  • tell your doctor and pharmacist if you are allergic to propafenone, any other medications, or any of the ingredients in propafenone tablets or extended-release capsules. Ask your doctor or pharmacist for a list of the ingredients.
  • tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: anticoagulants (‘blood thinners’) such as warfarin (Coumadin); certain antibiotics such as azithromycin (Zithromax), clarithromycin (Biaxin, in Prevpac), and erythromycin (E.E.S., others); antihistamines; beta-blockers such as atenolol (Tenormin), carteolol (Cartrol), labetalol (Normodyne, Trandate), metoprolol (Lopressor), nadolol (Corgard), propranolol (Inderal), sotalol (Betapace), and timolol (Blocadren); certain antidepressants such as desipramine (Norpramin) and imipramine (Tofranil);cimetidine (Tagamet); cisapride (Propulsid) (not available in the U.S.); digoxin (Lanoxin); haloperidol (Haldol); ketoconazole (Nizoral); lidocaine; medications for irregular heartbeat such as amiodarone (Cordarone, Pacerone), bepredil (not available in the U.S.), dofetilide (Tikosyn), disopyramide (Norpace), ibutilide (Corvert), procainamide, and quinidine (Quinaglute, others). medications for mental illness and nausea; orlistat (Alli, Xenical); ritonavir (Norvir); rifampin (Rifadin, Rimactane); saquinavir (Invirase); selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine (Prozac, Sarafem, in Symbyax), paroxetine (Paxil, Pexeva) and sertraline (Zoloft); and venlafaxine (Effexor).
  • tell your doctor if you have excessive diarrhea, sweating, vomiting, loss of appetite, or decreased thirst and if you have or have ever had a slow heartbeat; low blood pressure; low or high levels of sodium, potassium, chloride, or bicarbonate in your blood; heart failure; or asthma or any other condition that causes your airways to become narrow. Your doctor may tell you not to take propafenone.
  • in addition to the conditions listed in the WARNINGS and PRECAUTIONS section, tell your doctor if you have or have ever had a pacemaker; myasthenia gravis (a disorder of the nervous system that causes muscle weakness), or liver or kidney disease,
  • tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking propafenone, call your doctor.
  • if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking propafenone.
  • you should know that this medication may make you drowsy or dizzy. Do not drive a car or operate machinery until you know how it affects you.
  • tell your doctor if you use tobacco products. Cigarette smoking may decrease the effectiveness of this medication.

Dosage Of Propafenone

Propafenone comes as a tablet and an extended-release (long-acting) capsule to take by mouth. The tablet is usually taken three times a day, once every 8 hours. The extended-release capsule is usually taken two times a day, once every 12 hours, with or without food. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take propafenone exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Swallow the capsules whole; do not crush or open the capsules or divide the contents of a capsule into more than one dose.

You may begin taking propafenone in a hospital so that your doctor can monitor you carefully as your body gets used to the medication. Your doctor may start you on a low dose of propafenone and gradually increase your dose, not more often than once every 5 days.

Propafenone may control your irregular heartbeat, but will not cure it. Continue to take propafenone even if you feel well. Do not stop taking propafenone without talking to your doctor. Your heartbeat may become irregular if you suddenly stop taking propafenone.


Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.


All information has been provided courtesy of MedLinePlus from the National Library of Medicine and from the FDA.