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pronounced as (proe pa feen' one)


In clinical studies, people who had recently had a heart attack and took certain medications for irregular heartbeat that are similar to propafenone were more likely to die than people who did not take one of the medications. Propafenone may also cause life-threatening irregular heartbeat and increase the risk of death in certain patients. Tell your doctor if you have had a heart attack within the past two years or if you have heart disease.

Because of the risks of taking propafenone, it should be used only to treat life-threatening irregular heartbeat. Talk to your doctor about the risks of taking propafenone.

Your doctor may examine you and may order certain lab tests and electrocardiogram (EKG) tests to check your body's response to propafenone. Keep all appointments with your doctor and the laboratory.

Why is this medication prescribed?

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.

How should this medicine be used?

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.

Other uses for this medicine

This medication should not be prescribed for other uses; ask your doctor or pharmacist for more information.

What special precautions should I follow?

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 IMPORTANT WARNING 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.

What special dietary instructions should I follow?

Talk to your doctor about eating foods and salt substitutes that contain potassium.

Talk to your doctor about eating grapefruit and drinking grapefruit juice while you are taking this medication.

What should I do if I forget a dose?

Take the missed dose as soon as you remember it. However, if it is almost time for your next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What side effects can this medication cause?

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

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online ( or by phone (1-800-332-1088).

What should I know about storage and disposal of this medication?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach.

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website ( for more information if you do not have access to a take-back program.

In case of emergency/overdose

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Symptoms of overdose may include:

  • tiredness
  • slow or irregular heartbeat
  • seizures

What other information should I know?

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.

Brand names

  • Rythmol®
  • Rythmol® SR
Last Revised - 01/15/2018