Propafenone is a Class IC anti-arrhythmic that affects the way your heart beats.

Propafenone is used in certain situations to prevent serious heart rhythm disorders.

Propafenone may also be used for purposes not listed in this medication guide.

You should not use propafenone if you have heart failure, Brugada syndrome, sick sinus syndrome, AV block (without a pacemaker), severe low blood pressure, very slow heartbeats, a severe electrolyte imbalance, shortness of breath, or if you recently had a heart attack.

Propafenone may cause a new or worsening heartbeat pattern. Call your doctor at once if you have fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness.

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.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

You may take propafenone with or without food.

You may have very low blood pressure while taking this medication. Call your doctor if you are sick with vomiting or diarrhea, extreme thirst, loss of appetite, or if you are sweating more than usual.

You may need frequent blood tests. Your heart function may also need to be checked with an electrocardiograph or ECG (sometimes called an EKG), before and during treatment with propafenone.

Store at room temperature away from moisture, heat, and light. Keep the bottle tightly closed when not in use.

You should not use propafenone if you are allergic to it, or if you have:

• heart failure, or if you have recently had a heart attack;

• a genetic heart condition called Brugada syndrome;

• a serious heart condition such as "sick sinus syndrome" or "AV block" (unless you have a pacemaker);

• severe low blood pressure, or history of slow heart beats that have caused you to faint;

• a severe or uncontrolled electrolyte imbalance; or

• wheezing or shortness of breath.

Tell your doctor if you have ever had:

• a breathing disorder;

• liver or kidney disease;

• lupus;

• myasthenia gravis; or

• an abnormal blood test called Antinuclear Antibody Test or ANA.

Tell your doctor if you have a pacemaker or defibrillator. These devices may need to be re-programmed while you are taking propafenone.

Tell your doctor if you are pregnant or breast-feeding.

propafenone may affect fertility (ability to have children) in men. Talk with your doctor if you have concerns about this risk.

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

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. http://www.upandaway.org

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 (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

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.

Grapefruit may interact with propafenone and lead to unwanted side effects. Avoid the use of grapefruit products.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Propafenone may cause a new or worsening heartbeat pattern. Call your doctor at once if you have fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness (like you might pass out)

Also call your doctor at once if you have:

• shortness of breath (even with mild exertion);

• swelling in your arms or legs;

• sudden weight gain; or

• fever, chills, sore throat.

Common side effects of propafenone may include:

• irregular heartbeats;

• nausea, vomiting, constipation;

• headache, dizziness, tiredness; or

• unusual or unpleasant taste in your mouth.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective.

Propafenone can cause a serious heart problem. Your risk may be higher if you also use certain other medicines for infections, asthma, heart problems, high blood pressure, depression, mental illness, cancer, malaria, or HIV.

Many drugs can affect propafenone. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed here. Tell your doctor about all your current medicines and any medicine you start or stop using.

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.