Disopyramide (Norpace) is used to treat certain types of arrhythmias (irregular heartbeat). You'll typically first start the medication in a hospital so your provider can monitor you closely. Some common side effects of disopyramide (Norpace) include dry mouth, difficulty urinating, and constipation. It's available as an immediate-release (IR) and extended-release (ER) capsule. While the IR version is available as brand and lower-cost generic, the ER version is only sold under the brand name Norpace CR.
Ventricular arrhythmias (a type of irregular heart rhythm)
Disopyramide (Norpace) is an antiarrhythmic. It slows down abnormal electrical activity in your heart to treat irregular heart rhythm.
Source:Â DailyMed
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor as soon as possible if any of the following side effects occur:
More common
Dizziness, feeling of faintness
fainting
heartbeat sensations
shortness of breath
unusual tiredness
Less common
fast or slow heartbeat, rapid weight gain, swelling of feet or lower legs
lightheadedness
rash and/or itching
Rare
Enlargement of breasts in men
mental depression
nosebleeds or bleeding gums
sore throat and fever
yellow eyes or skin
Signs and symptoms of hypoglycemia (low blood sugar)
Anxious feeling
chills
cold sweats
confusion
cool, pale skin
drowsiness
fast heartbeat
headache
hunger (excessive)
nervousness
shakiness
unsteady walk
unusual tiredness or weakness
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Can ask provider to use immediate-release (IR) capsules to make a liquid for children or those who have trouble swallowing pills
Available as a controlled-release (CR) version that's taken less frequently
Not a preferred medication if you have heart failure or have had a recent heart attack
Requires close monitoring by provider
IR capsule is taken up to 4 times a day
It's best to take disopyramide (Norpace) around-the-clock, spacing out the doses by the same amount of time. For example, if you need to take the medication 4 times a day, try to take it every 6 hours.
You can take disopyramide (Norpace) with or without food.
For Norpace CR — the controlled-release (CR) version of disopyramide: Don't crush or chew the capsule because this could cause more medication than normal to be released and raise your risk of side effects. Let your provider know if you have trouble swallowing the whole pills.
It's common to have side effects like dry mouth, trouble urinating, and constipation while you're taking disopyramide (Norpace). If they become too bothersome, ask your provider if you can take a lower dose, but don't adjust the dose on your own.
Disopyramide (Norpace) can cause serious side effects, such as heart failure, other abnormal heart rhythms, and chest pain. It's important to get regular follow-up and tests done as recommended to catch side effects early on before they become serious.
Make sure you tell your provider and pharmacist about all of the medications you take, including supplements, so they can counsel you on drug interactions with disopyramide (Norpace). Using disopyramide (Norpace) with certain medications can be very dangerous because of the risk of serious side effects, including abnormal heart rhythms.
There isn't enough information to know if disopyramide (Norpace) is safe to take while you're pregnant or breastfeeding. This medication has been found in breast milk and can potentially harm breastfed babies. Discuss the risks and benefits of taking disopyramide (Norpace) with your provider.
Disopyramide (Norpace) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
The Cardiac Arrhythmia Suppression Trial (CAST) was a medical study that showed that it might be harmful and even life-threatening to take certain antiarrhythmic medications to prevent fatal abnormal heart rhythms after a recent heart attack (i.e., within 2 years). Since disopyramide (Norpace) is an antiarrhythmic, it's important to be aware of this risk. And for this reason, disopyramide (Norpace) is usually reserved for people who are already experiencing a life-threatening abnormal heartbeat. If you've had a heart attack recently, your heart specialist will decide which medication is best for you based on your symptoms and electrocardiogram (EKG) results.
Risk factors: History of heart failure | Low blood pressure | Heart muscle inflammation (myocarditis) or stiffening (cardiomyopathy)
Disopyramide (Norpace) can cause your heart to squeeze less with each beat. This can lead to new or worsening congestive heart failure. Disopyramide (Norpace) can also cause dangerously low blood pressure. You shouldn't take this medication if you already have severe heart failure or low blood pressure, unless it's caused by your arrhythmia condition. If you have any history of abnormal heart muscle function and you need to take disopyramide (Norpace), you'll need closer monitoring. Let your provider know right away if you have symptoms of low blood pressure (e.g, dizziness, lightheadedness, fainting) or heart failure (e.g., shortness of breath, swelling of feet or ankles). You might need to stop taking disopyramide (Norpace).
Disopyramide (Norpace) can slow down the electrical activity in certain parts of your heart. Some changes can lead to life-threatening arrhythmias, including worsened ventricular arrhythmia. Other electrical changes can cause you to have heart block. Your provider will monitor your heart's electrical activity using an electrocardiogram (EKG) on a regular basis and adjust your dose accordingly. If you notice an abnormally slow or fast pulse, chest pain or discomfort, weakness, dizziness, or fainting while taking disopyramide (Norpace), get medical help right away.
Risk factors: Heart failure | Poor nutrition | Liver or kidney problems | Taking other medications that lower blood sugar | Drinking alcohol
Although rare, some people had low blood sugar while they were taking disopyramide (Norpace). Getting low blood sugar from disopyramide (Norpace) might be more likely to happen in people with heart failure, poor nutrition, liver or kidney problems, or those who take medications that can affect blood sugar levels. Make sure to watch out for symptoms of low blood sugar, including shakiness, dizziness, sweating, difficulty concentrating, or feeling moody.
Risk factors: Glaucoma | Myasthenia gravis | History of prostate or bladder problems
Disopyramide (Norpace) can worsen symptoms of glaucoma, myasthenia gravis, or urinary retention (trouble emptying your bladder, common in men with prostate problems). Tell your provider if you have a family history of glaucoma, since you might need your eye pressure checked before you start disopyramide (Norpace). If you have myasthenia gravis, only take this medication if you don't have any other option since it can trigger a myasthenia gravis "crisis."
Risk factors: History of kidney or liver problems
Your kidneys are responsible for clearing disopyramide (Norpace) out of the body. Your liver also helps your body break down disopyramide (Norpace). If you have poor kidney or liver function, the medication might stay in the body longer, accumulate (build up), and cause more side effects. Note that having significant heart disease also puts you at risk of having liver problems.
To lower the risk of side effects because of poor kidney or liver health, you might need a lower dose of disopyramide (Norpace). Let your provider know if you know you have kidney or liver problems before starting treatment. They'll check your kidney and liver function and prescribe you an appropriate dose. If you have severe kidney problems, you might not be able to take the controlled-release version, Norpace CR.
Antiarrhythmics like disopyramide (Norpace) might not work as well if you have low levels of potassium. On the other hand, they might cause more side effects if your potassium levels are too high. Your provider will order blood draws to make sure your potassium levels are normal before giving you disopyramide (Norpace).
Disopyramide (Norpace) can interact with other medications. Some medications, such as phenytoin (Dilantin), can lower the levels of disopyramide (Norpace) in the body. As a result, disopyramide (Norpace) might work less well. Other medications can potentially cause your disopyramide (Norpace) levels to be too high, leading to more side effects. If necessary, your provider can check the level of disopyramide (Norpace) in your blood. Like disopyramide (Norpace), some other antiarrhythmics can cause abnormal electrical activity in the heart; this effect is more likely to happen if you take several antiarrhythmic medications at the same time. Tell your provider and pharmacist about all the medications that you take, so they can help you look out for dangerous interactions.
Immediate-release capsule (Norpace brand and generic)
Adults: The typical dose is 150 mg by mouth every 6 hours.
Children: Your child's dose will be based on their age and body weight. It's typically given by mouth every 6 hours.
Extended-release capsule (Norpace CR brand)
Adults: The typical dose is 300 mg by mouth every 12 hours.
Children: Ask your child's provider if the extended-release version is right for your child.
Your dose might differ if you weigh less than 110 pounds, have kidney or liver problems, or have certain specific heart problems. Your provider might adjust your dose if you experience side effects.
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Shock due to heart damage (cardiogenic shock)
Long QT syndrome (an inherited heart rhythm condition)
Ventricular arrhythmias (a type of irregular heart rhythm)
Treatment of atrial fibrillation or flutter
Prevention of atrial fibrillation or flutter
Prevention of ventricular arrhythmias
Life-threatening ventricular fibrillation that keeps coming back (when other antiarrhythmics haven't worked well)
Life-threatening tachycardia that keeps coming back (when other antiarrhythmics haven't worked)
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Echt, D. S., et al. (1991). Mortality and morbidity in patients receiving encainide, flecainide, or placebo – The Cardiac Arrhythmia Suppression Trial. The New England Journal of Medicine.
Hindricks, G., et al. (2022). 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation developed in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS): The Task Force for the diagnosis and management of atrial fibrillation of the European Society of Cardiology (ESC) Developed with the special contribution of the European Heart Rhythm Association (EHRA) of the ESC. European Heart Journal.
MedlinePlus. (2022). Cardiogenic shock.
National Heart, Lung, and Blood Institute. (2022). Arrhythmias: Long QT syndrome.
National Heart, Lung, and Blood Institute. (2022). Arrhythmias: Types.
Ommen, S. R., et al. (2020). 2020 AHA/ACC guideline for the diagnosis and treatment of patients with hypertrophic cardiomyopathy: A report of the American College of Cardiology/American Heart Association joint committee on clinical practice guidelines. Circulation.
Teva Pharmaceuticals USA, Inc. (2022). DISOPYRAMIDE PHOSPHATE capsule [package insert]. DailyMed.
Wendell, L. C., et al. (2011). Myasthenic crisis. The Neurohospitalist.
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