Propafenone is in a group of drugs called Class IC anti-arrhythmics. It 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 this medication if you are allergic to propafenone, or if you have untreated or uncontrolled congestive heart failure, a heart condition called "sick sinus syndrome" or "AV block" (unless you have a pacemaker), slow heartbeats or severely low blood pressure, an electrolyte imbalance, or a breathing disorder such as asthma.

Before you take propafenone, tell your doctor if you have congestive heart failure, liver or kidney disease, lupus, arthritis, myasthenia gravis, or if you have had a heart attack within the past 2 years.

Call your doctor at once if you have a serious side effect such as weak pulse, slow breathing, feeling like you might pass out, feeling short of breath, swelling, rapid weight gain, pale skin, easy bruising or bleeding, unusual weakness, confusion, unusual thoughts or behavior, or seizure.

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

• untreated or uncontrolled congestive heart failure;

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

• slow heartbeats or severely low blood pressure;

• a severe or uncontrolled electrolyte imbalance (such as low levels of potassium in your blood); or

• a breathing disorder such as severe COPD (chronic obstructive pulmonary disorder).

To make sure you can safely take propafenone, tell your doctor if you have any of these other conditions:

• congestive heart failure;

• a breathing disorder;

• liver disease;

• kidney disease;

• lupus;

• arthritis;

• myasthenia gravis; or

• if you have had a heart attack within the past 2 years.

FDA pregnancy category C. It is not known whether propafenone will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medication.

It is not known whether propafenone passes into breast milk or if it could harm a nursing baby. You should not breast-feed while you are using propafenone.