Norpace

(Disopyramide Phosphate)

The active ingredient in Norpace is disopyramide phosphate, which is an antiarrhythmic medication. Its mechanism of action involves blocking sodium channels in heart muscle cells, which slows electrical conduction and stabilizes the heart’s rhythm. This helps prevent irregular, fast, or dangerous heartbeats and allows the heart to pump more effectively and regularly.

Follow all directions given to you by your doctor and read all documents provided, including the full Prescribing Information, FDA-Approved Product Labeling, Instructions for Use, and Medication Guide before using Norpace. However, the following is a synopsis of the general guidelines for the use of Norpace:

• Norpace is taken by mouth as capsules.
• It may be prescribed as immediate-release Norpace or extended-release Norpace CR.
• Take the medication exactly as prescribed and at evenly spaced times.
• Do not crush or chew extended-release capsules.
• Norpace may be taken with or without food.
• Your dose may be adjusted based on response, side effects, kidney function, and heart rhythm monitoring.
• Regular medical visits, ECGs, and blood tests may be required.
• Do not stop taking Norpace suddenly without medical advice.

Some mild or common side effects of Norpace seen in clinical trials include:

• Dry mouth.
• Constipation.
• Blurred vision.
• Bloating or gas.
• Nausea.
• Dizziness or lightheadedness.
• Headache.
• Difficulty urinating.
• Fluid retention (edema) or weight gain
• Low blood pressure (hypotension).

Some individuals may experience serious side effects while using Norpace. These side effects may require immediate medical attention. If you experience any of the following, contact your healthcare provider or seek emergency medical help:

• Heart rhythm changes such as fast or irregular heartbeat, lightheadedness, dizziness, chest pain, and trouble breathing.
• Signs of heart failure include swelling, rapid weight gain, or trouble breathing.
• Very low blood pressure.
• Severe hypoglycemia.
• Muscle weakness, especially in people with myasthenia gravis.
• Allergic reactions such as hives, rash, shortness of breath, or swelling of the face or throat.

These are not all of the possible side effects of Norpace. You should always seek medical advice from your healthcare provider for any questions or concerns about your medical condition or treatment. Read all patient information, medication guides, or drug information sheets that come with this medication. You can also report adverse effects to the Food and Drug Administration at www.fda.gov/medwatch or 1-800-FDA-1088.

Before starting Norpace, it is crucial to discuss any existing health conditions with your healthcare provider. You should be sure that your healthcare provider is aware of all your medical conditions, including:

• Heart failure or cardiomyopathy.
• A history of heart attack.
• Heart block or have a pacemaker.
• Low blood pressure.
• Kidney disease or liver disease.
• Glaucoma.
• Urinary retention or prostate problems.
• Myasthenia gravis.
• Diabetes or blood sugar problems.
• A history of QT prolongation.
• Electrolyte imbalances.
• Are taking other heart rhythm medications.

Boxed Warning

Norpace has an FDA boxed warning.

Antiarrhythmic drugs, including Norpace, have been shown to increase the risk of death in patients with recent myocardial infarction.

Norpace should be used only for life-threatening ventricular arrhythmias.

The use of Norpace for less severe arrhythmias is generally not recommended because the risks may outweigh the benefits.

Norpace should not be used in patients with cardiogenic shock, second- or third-degree heart block without a pacemaker, congenital long QT syndrome, or known hypersensitivity to disopyramide. It may also not be suitable for patients with untreated glaucoma or urinary retention, and for those with myasthenia gravis.

Norpace begins working within a few hours of a dose, but stabilizing the heart rhythm may take up to a few weeks. Continuous monitoring is often required when treatment is started or adjusted.

When Norpace is taken with other prescription drugs, over-the-counter medications, vitamins, and supplements, it may change how they work or increase the frequency or severity of side effects. Make sure that you tell your healthcare professional about anything that you are taking to avoid any negative drug interactions, including:

• Quinidine or procainamide, due to the increased risk of heart rhythm problems.
• Flecainide, due to its additive antiarrhythmic effects.
• Verapamil or beta blockers, due to the increased risk of low blood pressure and heart block.
• Erythromycin or clarithromycin, due to increased disopyramide levels and QT prolongation.
• Ketoconazole, due to increased drug levels.
• Phenytoin, due to the reduced effectiveness of Norpace.
• Ziprasidone or thioridazine, due to the increased risk of QT prolongation.
• Dronedarone or dofetilide, due to serious heart rhythm interactions.
• Arsenic trioxide, due to the QT prolongation risk.

Norpace is available in immediate-release capsules and extended-release Norpace CR capsules.

Dosage summary based on prescribing information:

Immediate-release Norpace is typically started at 100 mg every 6 hours.

Extended-release Norpace CR is commonly prescribed at 200 mg every 12 hours.

Norpace is approved for use in adults.

It should be stored at room temperature, away from the reach of children or pets.

Norpace is manufactured by Pfizer.

Yes, disopyramide is available as a generic medication.

Do not stop taking Norpace without consulting your healthcare provider. Stopping suddenly may worsen heart rhythm problems. Your doctor will guide you on how to safely reduce or discontinue treatment if needed.

Norpace should only be used during pregnancy if the potential benefit outweighs the potential risk to the unborn baby. Inform your healthcare provider if you are pregnant or planning to become pregnant.

Disopyramide may pass into breast milk. Breastfeeding is generally not recommended while taking Norpace unless your healthcare provider determines that the benefits outweigh the potential risks to the infant.