Worst Pills, Best Pills

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Drug Profile

The information on this site is intended to supplement and enhance, not replace, the advice of a physician who is familiar with your medical history. Decisions about your health should always be made ONLY after detailed conversation with your doctor.

Limited Use [what does this mean?]
Generic drug name: disopyramide (dye soe PEER a mide)
Brand name(s): NORPACE
GENERIC: available FAMILY: Drugs for Abnormal Heart Rhythm
Find the drug label by searching at DailyMed.

Pregnancy and Breast-feeding Warnings [top]

Pregnancy Warning

This drug caused harm to developing fetuses in animal studies, including decreased implantation, growth, and survival. Use during pregnancy only for clear medical reasons. Tell your doctor if you are pregnant or thinking of becoming pregnant before you take this drug.

Breast-feeding Warning

Disopyramide is excreted in human milk. Because of the potential for serious adverse effects in nursing infants, you should not take this drug while nursing.

Safety Warnings For This Drug [top]


In the National Heart, Lung, and Blood Institute’s Cardiac Arrhythmia Suppression Trial (CAST) (a long-term, multicentered, randomized, double-blind study), in patients with asymptomatic non-life-threatening ventricular (the large chambers of the heart) arrhythmias (rhythm disturbances) who had a heart attack more than six days but less than two years previous, deaths or nonfatal cardiac arrest were seen in 7.7% of those patients treated with encainide or flecainide, members of the Class 1 group of antiarrhythmic drugs, compared to 3.0% in patients receiving an inactive sugar pill or placebo.

Because of the known ability of the Class 1 drugs, such as quinidine, to cause rhythm disturbances, and the lack of evidence of improved survival for any antiarrhythmic drug in patients without life-threatening heart rhythm disturbances, the use of the Class 1 drugs should be reserved for patients with life-threatening rhythm disturbances of the ventricles. These warnings now appear in the FDA-approved product labeling, or package insert, for all Class 1 drugs, including: disopyramide (NORPACE and generics), flecainide (TAMBOCOR), mexiletine (MEXITIL and generics), moricizine (ETHMOZINE), procainamide (PROCANBID and generics), propafenone (RYTHMOL), quinidine (DURAQUIN, QUINAGLUTE DURA-TABS, QUINIDEX, and generics), and tocainide (TONOCARD).


When this drug was used to treat rhythm disturbances of the small chambers of the heart (atria), it provided no survival advantage and a higher risk of serious adverse effects than older drugs such as digoxin, the beta-blockers, and the calcium channel blockers diltiazem and verapamil.[1],[2]

This drug is not approved by the FDA to treat rhythm disturbances of the atria.

Product Warnings

Ask a doctor or pharmacist before use if you are taking antibiotics.

When using this product, tiredness, drowsiness or dizziness may occur. Be careful driving or operating machinery.

Stop using and ask a doctor if symptoms get worse, diarrhea lasts more than two days or you get abdominal swelling or bulging. These may be signs of a serious condition.

If pregnant or breast-feeding, ask a health care professional before use.

Older adults are especially sensitive to the harmful anticholinergic effects of this drug. Drugs in this family should not be used unless absolutely necessary.

Mental Effects: confusion, delirium, short-term memory problems, disorientation and impaired attention.

Physical Effects: dry mouth, constipation, difficulty urinating (especially for a man with an enlarged prostate), blurred vision, decreased sweating with increased body temperature, sexual dysfunction and worsening of glaucoma.

Facts About This Drug [top]

Disopyramide slows the heart rate and stabilizes irregular heartbeats (arrhythmias).


Disopyramide is linked to a high incidence of congestive heart failure and problems with urination, so people with these medical problems should not use the drug.[3] Since there is a narrow range between a helpful and a harmful amount of this drug in your body, call your doctor immediately if you experience these adverse effects or any of those listed under Adverse Effects. If you have decreased...

Disopyramide slows the heart rate and stabilizes irregular heartbeats (arrhythmias).


Disopyramide is linked to a high incidence of congestive heart failure and problems with urination, so people with these medical problems should not use the drug.[3] Since there is a narrow range between a helpful and a harmful amount of this drug in your body, call your doctor immediately if you experience these adverse effects or any of those listed under Adverse Effects. If you have decreased kidney function, you should be taking less than the usual dose of disopyramide.[3]


Many people who are taking disopyramide or another drug in its family have relatively mild disturbances in their heart rhythm and no symptoms of underlying heart disease. The vast majority of these people do not need these drugs, and there is no evidence that using them improves health. In fact, most of the drugs in this family have severe adverse effects that are sometimes worse and even more life-threatening than the irregular heartbeats they treat. All of these drugs can also cause new irregularities in your heartbeat.


If you have an irregular heartbeat without any symptoms of underlying heart disease, you should not be exposed to the dangers of a drug that has no health benefit for your condition.[4] If you are taking disopyramide or another drug in its family for an irregular heartbeat, talk to your doctor and find out whether you also have symptoms of underlying heart disease. If not, discuss the possibility of stopping the drug.


Disopyramide remains on a well-recognized list of drugs that are inappropriate for use in older adults because it may induce heart failure in older adults and is strongly anticholinergic.[5]


In 2015, a study published in JAMA Internal Medicine showed that strong anticholinergic drugs, such as disopyramide, were associated with an increased risk of dementia in older adults. The study also showed that higher doses and longer use of these drugs are associated with a higher risk of dementia.[6]


Refer to the August 2015 issue of Worst Pills, Best Pills News for examples of strong anticholinergic drugs.

Before You Use This Drug [top]

Do not use if you have or have had:

  • complete heart block
  • shock due to heart failure
  • QT interval prolongation (congenital)

Tell your doctor if you have or have had:

  • allergies to drugs
  • diabetes
  • any heart problems
  • enlarged prostate gland
  • glaucoma
  • kidney function impairment
  • liver function impairment
  • too much or too little blood potassium or magnesium
  • myasthenia gravis
  • urinary obstruction
  • pregnancy or are breast-feeding
  • low blood pressure

Tell your doctor about any other drugs you take, including aspirin, herbs, vitamins, and other nonprescription products.

When You Use This Drug [top]

  • Until you know how you react to this drug, do not drive or perform other activities requiring alertness. Disopyramide may cause dizziness.
  • You may feel dizzy when rising from a lying or sitting position. When getting out of bed, hang your legs over the side of the bed for a few minutes, then get up slowly. When getting up from a chair, get up slowly and stay beside the chair until you are sure that you are not dizzy.
  • Notify your physician and take sugar if symptoms of low blood sugar appear.
  • Take precautions during exercise or hot weather because of possible reduced sweating.
  • Do not stop taking this drug suddenly. Your doctor must give you a schedule to lower your dose gradually, to prevent serious changes in heart function.
  • Wear a medical identification bracelet or carry a card stating that you take this drug.
  • If you plan to have any surgery, including dental, tell your doctor that you take this drug.

How to Use This Drug [top]

  • If you miss a dose, take it as soon as you remember, but skip it if it is less than four hours (eight hours if you are taking extended-release capsules) until your next scheduled dose. Do not take double doses.
  • Do not share your medication with others.
  • Take the drug at the same time(s) each day.
  • Take with food or milk.
  • Swallow extended-release tablets whole. Do not crush or break.
  • Store at room temperature with lid on tightly. Do not store in the bathroom. Do not expose to heat, moisture, or strong light. Keep out of reach of children.

Interactions with Other Drugs [top]

The following drugs, biologics (e.g., vaccines, therapeutic antibodies), or foods are listed in Evaluations of Drug Interactions 2003 as causing “highly clinically significant” or “clinically significant” interactions when used together with any of the drugs in this section. In some sections with multiple drugs, the interaction may have been reported for one but not all drugs in this section, but we include the interaction because the drugs in this section are similar to one another. We have also included potentially serious interactions listed in the drug’s FDA-approved professional package insert or in published medical journal articles. There may be other drugs, especially those in the families of drugs listed below, that also will react with this drug to cause severe adverse effects. Make sure to tell your doctor and pharmacist the drugs you are taking and tell them if you are taking any of these interacting drugs:

AVELOX, BETAPACE, charcoal, DILANTIN, EES, ERYTHROCIN, erythromycin, halofantrine, ISORDIL, isosorbide dinitrate, mizolastine, moxifloxacin, NORVIR, ORAP, phenytoin, pimozide, PRIFTIN, rifapentine, ritonavir, SORBITRATE, sotalol, sparfloxacin, ZAGAM, zotepine.

Adverse Effects [top]

Call your doctor immediately if you experience:

  • difficulty urinating
  • chest pains
  • confusion
  • dizziness, lightheadedness, or fainting
  • unusual tiredness
  • muscle weakness
  • shortness of breath
  • swelling of feet or lower legs
  • unusually fast or slow heartbeat
  • rapid weight gain
  • rash and/or itching
  • enlargement of breasts in men
  • nosebleeds or bleeding gums
  • depression
  • sore throat and fever
  • yellow eyes and skin
  • signs of low blood sugar: anxious feeling, chills, cold sweats, confusion, cool pale skin, drowsiness, headache, excessive hunger, nausea, nervousness, rapid heartbeat, shakiness, unsteady walk, unusual tiredness or weakness

Call your doctor if these symptoms continue:

  • dry mouth, throat, eyes, or nose (relieve by sucking ice or chewing sugarless gum)
  • bloating or stomach pain
  • blurred vision
  • decreased sexual ability
  • loss of appetite
  • nausea
  • nervousness
  • frequent urge to urinate
  • constipation
  • diarrhea
  • headache
  • trouble sleeping


Periodic Tests[top]

Ask your doctor which of these tests should be done periodically while you are taking this drug:

  • blood pressure
  • heart function tests, such as electrocardiogram (ECG, EKG)
  • kidney function tests
  • liver function tests
  • blood levels of glucose and potassium
  • eye pressure exams


last reviewed December 31, 2023