Norpace CR

Name: Norpace CR


Mechanism of action

Direct membrane depressant that decreases conduction velocity, prolongs refractoriness, decreases automaticity and reduces repolarization abnormalities


Bioavailability: 60-83%

Peak Plasma Time: 1-2.5 hr (immediate-release); 4-7 hr (controlled-release)

Onset: 30 min-3.5 hr

Duration: 1.5-8.5 hr


Protein Bound: 20-60%

Vd: 0.8-2 L/kg


Metabolised by CYP3A4 in liver (45%) and intestinal wall (16%)

Metabolites: N-monodealkylated metabolite (active met w/ less antiarrhythmic activity, but greater anticholinergic activity)


Half-Life: 4-10 hr (parent drug); 12.9 hr (metabolite: N-monodealkylated metabolite)

Total Body Clearance: 1-2 mL/min/kg

Renal Clearance: 107 mL/min

Excretion: urine (40-80%); feces (10-15%)

Dialyzable: Yes, maintenance dose after dialysis is recommended

Side Effects of Norpace CR

Serious side effects have been reported with Norpace CR. See the “Norpace CR Precautions” section.

Common side effects include:

  • dry mouth
  • difficult urination
  • constipation
  • blurred vision
  • dry eyes, nose, and throat
  • urinary retention
  • frequent urination
  • nausea
  • bloating and gas pains
  • dizziness
  • fatigue
  • muscle weakness
  • headache

This is not a complete list of Norpace CR side effects. Ask your doctor or pharmacist for more information.

Tell your doctor if you have any side effect that bothers you or that does not go away.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Norpace CR Interactions

Tell your doctor about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take:

  • medications that block a protein in the body (CYP3A4) such as some macrolide antibiotics (clarithromycin, telithromycin), some HIV protease inhibitors (indinavir, nelfinavir, ritonavir, saquinavir), some HCV protease inhibitors (boceprevir, telaprevir), some azole antifungals (ketoconazole, itraconazole, posaconazole, voriconazole), conivaptan (Vaprisol), delavirdine (Rescriptor), and nefazodone
  • verapamil
  • phenytoin

This is not a complete list of Norpace CR drug interactions. Ask your doctor or pharmacist for more information.

Norpace CR Food Interactions

Medications can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of Norpace CR, there are no specific foods that you must exclude from your diet when receiving this medication.

Inform MD

Before taking Norpace CR, tell your doctor about all of your medical conditions. Especially tell your doctor if you:

  • are allergic to disopyramide (Norpace CR) or any other drugs.
  • have or have ever had congestive heart disease, high blood pressure, diabetes, kidney or liver disease, glaucoma, myasthenia gravis, urinary retention, or benign prostatic hypertrophy.
  • are pregnant, plan to become pregnant, or are breast-feeding. 
  • are having surgery, including dental surgery
  • use cigarettes and caffeine-containing beverages. These products may increase the irritability of your heart and interfere with the action of Norpace CR.

Norpace CR can make you drowsy. Do not drive a car or operate machinery until you know how this medication affects you. Alcohol can add to the drowsiness caused by this medication.

Talk to your doctor about the risks and benefits of taking Norpace CR if you are 65 years of age or older. Older adults should not usually take Norpace CR because it is not as safe or effective as other medications that can be used to treat the same condition.

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements.

Norpace CR Usage

Take Norpace CR exactly as prescribed.

Norpace CR comes in capsule form and is taken twice every day. 

Do not cut, crush, or chew extended-release capsules; swallow them whole.

If you forget a dose, take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

Norpace CR Dosage

The dosage of Norpace CR must be individualized for each patient on the basis of response and tolerance.

The usual adult dosage of Norpace CR is 400 to 800 mg per day given in divided doses.

The recommended dosage for most adults is 600 mg/day given in divided doses (300 mg every 12 hours).

For patients whose body weight is less than 110 pounds (50 kg), the recommended dosage is 400 mg/day given in divided doses (200 mg every 12 hours). 

What is Norpace CR (disopyramide)?

Disopyramide affects the way that your heart beats.

Disopyramide is used to treat life-threatening irregular heartbeat patterns.

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

What happens if I overdose?

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

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

Consumer Information Use and Disclaimer

  • If your symptoms or health problems do not get better or if they become worse, call your doctor.
  • Do not share your drugs with others and do not take anyone else's drugs.
  • Keep a list of all your drugs (prescription, natural products, vitamins, OTC) with you. Give this list to your doctor.
  • Talk with the doctor before starting any new drug, including prescription or OTC, natural products, or vitamins.
  • Some drugs may have another patient information leaflet. Check with your pharmacist. If you have any questions about this medicine, please talk with your doctor, nurse, pharmacist, or other health care provider.
  • If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

This information should not be used to decide whether or not to take Norpace CR (disopyramide sustained-release capsules) or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to Norpace CR. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using this medicine.

Review Date: October 4, 2017