Norpace CR affects the way that your heart beats.

Norpace CR is used to treat life-threatening irregular heartbeat patterns.

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

You should not use Norpace CR if you have long QT syndrome, or a serious heart condition such as "AV block" (unless you have a pacemaker).

Do not use Norpace CR to treat any heart rhythm disorder that has not been checked and diagnosed by your doctor.

Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Your doctor may want to give your first dose of this medicine in a hospital or clinic setting to quickly treat any serious side effects that occur.

Do not crush, chew, break, or open an extended-release capsule. Swallow it whole.

Your heart function may need to be checked using an electrocardiograph or ECG (sometimes called an EKG).

Do not skip doses or change your dosing schedule without your doctor's advice. Sudden changes in the way you take Norpace CR can make your condition worse.

Store at room temperature away from moisture and heat.

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

• long QT syndrome; or

• a serious heart condition such as "AV block" (unless you have a pacemaker).

Do not use Norpace CR to treat any heart rhythm disorder that has not been checked and diagnosed by your doctor.

To make sure Norpace CR is safe for you, tell your doctor if you have:

• other heart rhythm disorders ("sick sinus syndrome", bundle branch block, Wolff-Parkinson-White syndrome);

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

• low blood pressure;

• low potassium levels in your blood (hypokalemia);

• low blood sugar, or diabetes;

• liver or kidney disease;

• enlarged prostate, bladder obstruction or other urination problems;

• glaucoma;

• myasthenia gravis; or

• if you are malnourished.

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

Disopyramide can pass into breast milk and may harm a nursing baby. You should not breast-feed while using this medicine.

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose of Norpace CR can be fatal.

Overdose symptoms may include trouble breathing, irregular heartbeats, and loss of consciousness.

Norpace CR may cause blurred vision and may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert and able to see clearly.

Drinking alcohol can increase certain side effects of disopyramide.

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

Norpace CR may cause serious side effects. Call your doctor at once if you have:

• a new or a worsening irregular heartbeat pattern;

• little or no urinating, painful or difficult urination;

• a light-headed feeling, like you might pass out;

• shortness of breath (even with mild exertion), swelling, rapid weight gain; or

• low blood sugar (headache, hunger, weakness, sweating, confusion, irritability, dizziness, fast heart rate, or feeling jittery).

Serious side effects such as heart failure or kidney problems may be more likely in older adults.

Common side effects of Norpace CR may include:

• dry mouth, nose, or throat;

• nausea, stomach pain, bloating;

• constipation;

• dry eyes, blurred vision;

• headache, tiredness, general ill feeling; or

• muscle pain or weakness.

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.

Many drugs can interact with Norpace CR. Not all possible interactions are listed here. Tell your doctor about all your medications and any you start or stop using, especially:

• ketoconazole;

• an antibiotic--clarithromycin, erythromycin; or

• other heart rhythm medicines--encainide, flecainide, propranolol, propafenone, quinidine.

This list is not complete and many other drugs can interact with Norpace CR. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Give a list of all your medicines to any healthcare provider who treats you.