Norpace (Disopyramide) - Oral

Warning:

The Food and Drug Administration (FDA) has issued a boxed warning for Norpace. Boxed warnings are the agency’s strongest warnings for serious and potentially life-threatening risks.

The boxed warning:

Taking antiarrhythmic drugs such as Norpace may increase the risk of death. Tell your healthcare provider if you experience any heart disease such as a valve problem or heart failure (HF), a condition when the heart cannot pump enough blood to other body parts.

In case of symptoms such as irregular heartbeat or chest pain, call your healthcare provider. Norpace may increase the chance of having arrhythmias (irregular heartbeats). Don't use Norpace in people without life-threatening arrhythmias.

What Is Norpace?

Norpace (disopyramide) is an orally administered prescription medication used to treat life-threatening abnormal heart rhythm problems in adults 18 and older.

Norpace contains the active drug, disopyramide, which belongs to the antiarrhythmic 1A drugs class.

The antiarrhythmic 1A drugs class refers to a grouping of drugs defined as sodium channel blockers that block fast sodium channels, therefore slowing conduction in fast-channel tissues.

Most antiarrhythmic drugs are grouped into four main classes, and it's important to know that these class I drugs are subdivided based on the specific kinetics (the rate of reaction) of their sodium channel effects.

Norpace works by blocking the electrical signals in the heart that causes abnormal heartbeats, making your heart more resistant to abnormal activity.

Containing the primary ingredient disopyramide, Norpace is a prescription drug available in the form of immediate-release (IR) tablets called Norpace, and extended-release (ER) capsules, under the brand name Norpace CR. Disopyramide is also available as a generic product administered via IR tablets.

This article will highlight both the orally administered IR tablets of Norpace and the ER capsule of Norpace CR.

For context, ER capsules slowly release the drug to work for a longer duration while IR capsules instantaneously disintegrate to make the drug immediately available for absorption.

Drug Facts

Generic Name: Disopyramide

Brand Name(s): Norpace, Norpace CR

Drug Availability: Prescription

Therapeutic Classification: Antiarrhythmic 1A

Available Generically: Yes

Controlled Substance: N/A

Administration Route: Oral

Active Ingredient: Disopyramide phosphate

Dosage Form(s): IR tablets, ER capsules

What Is Norpace Used For?

The FDA has approved Norpace for the treatment of documented and life-threatening ventricular arrhythmias, such as sustained ventricular tachycardia (ventricular rhythm faster than 100 beats per minute lasting at least 30 seconds).

Ventricular arrhythmias are abnormal heartbeats that originate in your lower heart chambers, called ventricles. Abnormal heartbeats often manifest themselves in the form of a heartbeat that beats too quickly (tachycardia) or a heart that beats too slowly (bradycardia).

There are limitations associated with the use of Norpace, including:

  • Use of Norpace is not recommended in lesser arrhythmias.
  • Avoid use in people with asymptomatic ventricular premature contractions.
  • Initiation of treatment with Norpace to treat life-threatening arrhythmias should be carried out in a hospital setting.
  • Don't use Norpace initially if rapid plasma levels of the drug are required.
  • Antiarrhythmic drugs do not enhance the survival rate in ventricular arrhythmias.

How to Take Norpace

Read the information leaflet before taking medicine.

Ask your healthcare provider if you have questions or don't understand any of the following:

  • Norpace is available as IR tablets and ER capsules.
  • Take the IR tablets every six to eight hours or as prescribed. 
  • Take ER capsules every 12 hours or as prescribed.
  • Swallow the ER capsule whole. Don't break, open, or crush the capsules.
  • Take the medicine as prescribed.
  • Norpace controls but does not cure ventricular arrhythmias. 
  • Don't stop taking it without talking to your healthcare provider, even if your condition improves.

Storage

Store at 77 degrees F. Keep your medications tightly closed and out of the reach of children and pets, ideally locked in a cabinet or closet. Do not store your medication in the bathroom.

Avoid pouring unused and expired drugs down the drain or in the toilet. Ask your pharmacist or healthcare provider about the best ways to dispose of this medicine.

Visit the FDA's website to know where and how to discard all unused and expired drugs. You can also find disposal boxes in your area. Ask your pharmacist or healthcare provider if you have any questions about the best ways to dispose of your medications.

If you travel with Norpace, get familiar with your final destination's regulations. In general, be sure to make a copy of your Norpace prescription.

Keep your medication in its original container from your pharmacy with your name on the label. Ask your healthcare provider if you have any questions about traveling with your medicine.

Off-Label Uses

Disopyramide has been used in the treatment of hypertrophic cardiomyopathy (HCM). HCM is a relatively common condition in which the heart muscle becomes thick and unable to pump blood normally.

How Long Does Norpace Take to Work?

Norpace is rapidly and almost completely absorbed after oral intake and reaches its peak plasma levels (when the drug is most concentrated in the bloodstream) in about two hours. However, depending on whether you take IR tablets or ER capsules, the time of impact and absorption will vary.

What Are the Side Effects of Norpace?

This is not a complete list of side effects, and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or a healthcare provider. You may report side effects to the FDA at fda.gov/medwatch or 800-FDA-1088.

Common Side Effects

Common side effects of Norpace include:

Call your healthcare provider if your symptoms worsen.

Severe Side Effects

The FDA has issued a boxed warning for Norpace. Boxed warnings are the agency’s strongest warnings for serious and potentially life-threatening risks.

The boxed warning:

Taking antiarrhythmic drugs such as Norpace may increase the risk of death. Tell your healthcare provider if you experience any heart disease such as a valve problem or heart failure.

In case of symptoms such as irregular heartbeat or chest pain, call your healthcare provider. Norpace may increase the chance of having arrhythmias. Don't use Norpace in people without life-threatening arrhythmias.

Contact your healthcare provider immediately if you develop any signs of a severe reaction. Call 911 if your symptoms feel life-threatening.

Serious side effects and their symptoms include:

  • Angina (chest pain)
  • Cardiac arrhythmias
  • Shortness of breath
  • Sudden changes in mental status
  • Edema (swelling of the feet, hands, or other parts of the body)
  • Unusual weight gain

Report Side Effects

Norpace may cause other side effects. Call your healthcare provider if you have unusual problems while taking this medication.

If you experience a serious side effect, you or your provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Norpace Should I Take?

Drug Content Provided and Reviewed by IBM Micromedex®

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For treatment of arrhythmias:
    • For short-acting oral dosage form (capsules):
      • Adults—100 to 150 mg taken every six to eight hours.
      • Children—Dose is based on body weight and age and must be determined by your doctor. The dose is usually 6 to 30 mg per kilogram (kg) (2.73 to 13.64 mg per pound) of body weight per day. This dose is evenly divided and taken every six hours.
    • For long-acting oral dosage forms (extended-release capsules or tablets):
      • Adults—200 or 400 mg every twelve hours.
      • Children—Use is not recommended.

Modifications

The following modifications (changes) should be kept in mind when using Norpace:

Severe allergic reaction: Avoid using Norpace if you have a known allergy to it or its ingredients. Ask your pharmacist or healthcare provider for a complete list of the ingredients if you're unsure.

Pregnancy: We don't know enough about the safety and effectiveness of Norpace in pregnant people and the unborn fetus. Discuss with your healthcare provider if you plan to become pregnant or are pregnant, and weigh the benefits and risks of taking Norpace during your pregnancy.

Breastfeeding: The metabolites of Norpace are present in human breast milk. Talk with your healthcare provider if you plan to breastfeed, to weigh the benefits and risks of taking Norpace while nursing and the different ways to feed your baby.

Adults over 65: Clinical studies haven't included a large enough number of people in this age group to see whether they respond differently from younger adults. Older adults with several medical conditions or taking several medications should use Norpace cautiously.

The dose selection should be toward the lower dosing end, attributing to decreased renal and hepatic functions. Older adults might also be more sensitive to Norpace side effects.

Children: The safety and effectiveness of Norpace have not been established in children.

Other modifications: The kidney excretes Norpace, and the risk of toxic reactions to this drug may be greater in people with impaired renal function. Carefully select the dose and monitor renal function.

Missed Dose

If you accidentally forgot your Norpace dose, take it as soon as you remember.

If it's already close to your next scheduled dose, skip the missed dose and take the following dose at your next scheduled dosing time. Don't try to double up to make up for the missed dose.

Try to find ways that work for you to help yourself remember to routinely keep your appointments and take your medication. If you miss too many doses, Norpace might be less effective at preventing your condition.

Overdose: What Happens If I Take Too Much Norpace?

If you think that you're experiencing an overdose or life-threatening symptoms, however, seek immediate medical attention.

The symptoms of a suspected overdose of Norpace include:

What Happens If I Overdose on Norpace?

If you think you or someone else may have overdosed on Norpace, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Norpace, call 911 immediately.

Precautions

Drug Content Provided and Reviewed by IBM Micromedex®

Your doctor should check your progress at regular visits to make sure the medicine is working properly.

Do not stop taking this medicine without first checking with your doctor. Stopping suddenly may cause a serious change in heart function .

Dizziness, lightheadedness, or fainting may occur, especially when you get up from a lying or sitting position. This is due to lowered blood pressure. Getting up slowly may help. This effect does not occur often at doses of disopyramide usually used; however, make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are not alert. If the problem continues or gets worse, check with your doctor.

Disopyramide may rarely cause hypoglycemia (low blood sugar) in some people. (See the Side Effects of This Medicine section below.) If these signs appear, eat or drink a food containing sugar and call your doctor right away.

This medicine may cause blurred vision or other vision problems. If any of these occur, do not drive, use machines, or do anything else that could be dangerous if you are not able to see well.

Disopyramide may cause dryness of the eyes, mouth, and nose. For temporary relief of mouth dryness, use sugarless candy or gum, melt bits of ice in your mouth, or use a saliva substitute. However, if dry mouth continues for more than 2 weeks, check with your medical doctor or dentist. Continuing dryness of the mouth may increase the chance of dental disease, including tooth decay, gum disease, and oral yeast infections.

This medicine often will make you sweat less, allowing your body temperature to increase. Use extra care not to become overheated during exercise or hot weather while you are taking this medicine, since becoming overheated could possibly result in heatstroke.

What Are Reasons I Shouldn’t Take Norpace?

Norpace is not encouraged for those with the following conditions:

What Other Medications May Interact With Norpace?

Use caution when taking Norpace with the following medications:

Your healthcare provider may need to adjust the dose of these drugs when used with Norpace.

And be sure to talk with your healthcare provider about any other medicines you take or plan to take, including over-the-counter (OTC), nonprescription products, vitamins, herbs, or plant-based medicines.

What Medications Are Similar?

Other drugs that work similarly to Norpace (medications used to treat ventricular arrhythmias) and that are also classified as 1A antiarrhythmic drugs include:

Frequently Asked Questions

  • What is Norpace?

    Norpace is an antiarrhythmic drug used to treat life-threatening irregular heartbeats. It contains the active drug, disopyramide, which belongs to the antiarrhythmic 1A drugs class.

  • How does Norpace work?

    Norpace works by blocking the electrical signals in the heart that causes abnormal heartbeats, therefore, making your heart more resistant to abnormal activity.

  • Can I take Norpace while I am pregnant or breastfeeding?

    There is not enough data available about the use of Norpace in pregnant and breastfeeding people. Ask your healthcare provider if you are pregnant or breastfeeding before using this drug.

    The drug should only be used if the benefit outweighs the risk.

How Can I Stay Healthy While Taking Norpace?

Heart arrhythmias can be a life-threatening condition and can negatively affect your quality of life.

As such, you may have tried different approaches or treatments. However, when prescribed Norpace, refer below for some specific tips on how to support your health while taking the medication:

  • Take your medications as recommended by your healthcare provider.
  • Don't skip the doses.
  • Achieve a healthy lifestyle to prevent the worsening of heart rhythm.
  • Consider working with a registered health practitioner to help you identify and manage your condition.
  • Talk to your healthcare provider before taking Norpace; if you become pregnant or breastfeeding.
  • Don't discontinue taking your medicine without asking your healthcare provider, even if you feel better.
  • Keep a close check on your symptoms. In case of chest pain or irregular heartbeat, immediately contact your healthcare provider.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended as a replacement for medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Prescribers' Digital Reference. Disopyramide phosphate - drug summary

  3. Merck Manual. Professional version. Drugs for arrhythmias.

  4. Priori SG, Blomström-Lundqvist C, Mazzanti A, et al. 2015 ESC guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: the task force for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death of the European Society of Cardiology (ESC). Endorsed by: Association for European Paediatric and Congenital Cardiology (AEPC). Eur Heart J. 2015;36(41):2793-2867. doi:10.1093/eurheartj/ehv316

  5. Food and Drug Administration. Drugs@FDA: FDA-approved drugs.

  6. Stanford Health Care. Types of ventricular arrhythmias.

  7. Sanchez-Nadales A, Anampa-Guzmán A, Khan A. Disopyramide for hypertrophic cardiomyopathyCureus. 2019;11(4):e4526. doi:10.7759/cureus.4526

  8. American Heart Association. Hypertrophic cardiomyopathy (HCM).

  9. Dailymed. Norpace label.