In the U.S.—

In Canada—

• Antiarrhythmic

Disopyramide ( dye-soe-PEER-a-mide) is used to treat abnormal heart rhythms.

It is available only with your doctor's prescription, in the following dosage forms:

Oral
• Capsules (U.S. and Canada)
• Extended-release capsules (U.S.)
• Extended-release tablets (Canada)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For disopyramide, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to disopyramide. Also tell your health care professional if you are allergic to any other substance, such as foods, preservatives, or dyes.

Pregnancy—Disopyramide has not been studied in pregnant women. However, use of disopyramide in a small number of pregnant women seems to show that this medicine may cause contractions of the uterus. Studies in animals have shown that disopyramide increases the risk of miscarriages. Before taking this medicine, make sure your doctor knows if you are pregnant or if you may become pregnant.

Breast-feeding—Disopyramide passes into breast milk.

Children—This medicine has been tested in children and has not been shown to cause different side effects or problems than it does in adults.

Older adults—Some side effects, such as difficult urination and dry mouth, may be especially likely to occur in elderly patients, who are usually more sensitive than younger adults to the effects of disopyramide.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking disopyramide, it is especially important that your health care professional know if you are taking any of the following:

• Antidepressants, tricyclic, such as amitriptyline (e.g., Elavil), clomipramine (e.g., Anafranil), desipramine (e.g., Norpramin), doxepin (e.g., Sinequan), imipramine (e.g., Tofranil), and nortriptyline (e.g., Pamelor) or
• Astemizole (e.g., Hismanal) or
• Chloroquine (e.g., Aralen) or
• Clarithromycin (e.g., Biaxin) or
• Cisapride (e.g., Propulsid) or
• Diphenhydramine (e.g., Benadryl) or
• Erythromycin (e.g., Erythrocin, Erytab) or
• Fludrocortisone (e.g., Florinef) or
• Halofantrine (e.g., Halfan) or
• Haloperidol (e.g., Haldol) or
• Indapamide (e.g., Lozol) or
• Maprotiline (e.g., Ludiomil) or
• Other heart medicine, including amiodarone (e.g., Cordarone); bepridil (e.g., Bepadin, Vascor); beta-adrenergic blocking agents, such as propranolol (e.g., Inderal) or sotalol (e.g., Betapace, Sotacor); diltiazem (e.g., Cardizem); encainide (e.g., Encaid); flecainide (e.g., Tambocor); ibutilide (e.g., Corvert); lidocaine (e.g., Xylocaine); procainamide (e.g., Procanbid); propafenone (e.g., Rythmol); quinidine (e.g., Quinidex); tocainide (e.g., Tonocard); and verapamil (e.g., Calan, Isoptin) or
• Pentamidine (e.g., NebuPent, Pentam) or
• Phenothiazines (chlorpromazine [e.g., Thorazine], prochlorperazine [e.g., Compazine], thioridazine [e.g., Mellaril]) or
• Pimozide (e.g., Orap) or
• Risperidone (e.g., Risperdal) or
• Sparfloxacin (e.g., Zagam) or
• Tamoxifen (e.g., Nolvadex) or
• Thiothixene (e.g., Navane) or
• Trimethoprim and sulfamethoxazole combination (e.g., Bactrim, Septra)—Effects on the heart may be increased

• Diabetes mellitus (sugar diabetes)—Disopyramide may cause low blood sugar

• Difficult urination or
• Enlarged prostate—Disopyramide may cause difficult urination

• Electrolyte disorders—Disopyramide may worsen heart rhythm problems

• Glaucoma (history of) or
• Myasthenia gravis—Disopyramide may aggravate these conditions

• Kidney disease or
• Liver disease—Effects may be increased because of slower removal of disopyramide from the body

• Low blood pressure or
• Other heart disorders—Effects of disopyramide on the heart may make these conditions worse

• Malnutrition, long term—Disopyramide may cause low blood sugar

Take disopyramide exactly as directed by your doctor even though you may feel well. Do not take more medicine than ordered.

For patients taking the extended-release capsules :

• Swallow the capsule whole without breaking, crushing, or chewing.

For patients taking the extended-release tablets:

• Do not crush or chew the tablet.

This medicine works best when there is a constant amount in the blood. To help keep the amount constant, do not miss any doses. Also, it is best to take the doses at evenly spaced times day and night. For example, if you are to take four doses a day, the doses should be spaced about 6 hours apart. If this interferes with your sleep or other daily activities, or if you need help in planning the best times to take your medicine, check with your health care professional.

Dosing—

The dose of disopyramide 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 disopyramide. If your dose is different, do not change it unless your doctor tells you to do so.

The number of tablets or capsules that you take depends on the strength of 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.

Missed dose—

If you miss a dose of this medicine, take it as soon as possible unless the next scheduled dose is in less than 4 hours. If you do not remember until later, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

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.

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
  • Chest pain;  fast or slow heartbeat, rapid weight gain, swelling of feet or lower legs;  lightheadedness;  rash and/or itching 
  
  

• Rare
  • Enlargement of breasts in men;  fever ;  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);  nausea;  nervousness;  shakiness;  unsteady walk;  unusual tiredness or weakness 
  
  

Other 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. However, check with your health care professional if any of the following side effects continue or are bothersome:

• More common
  • Blurred vision;  constipation;  dry eyes, mouth, nose, or throat;  problems with urination 
  
  

• Less common
  • Bloating or stomach pain;  diarrhea;  headache;  impotence;  loss of appetite;  muscle weakness;  nausea;  nervousness;  trouble in sleeping 
  
  

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.