Disopyramide belongs to the class of medications called antiarrhythmics. It is used to treat abnormal heart rhythms. It works in various areas of the heart to help normalize abnormal heart rhythms.

The dose of disopyramide is individualized for each person, depending on the person’s weight and response to the medication. The usual dose of disopyramide capsules is 100 mg to 200 mg every 6 hours. In certain circumstances, the doctor may start with a higher dose for the first dose only. People with reduced kidney or liver function may need lower daily doses.

Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Do not take this medication if you:

• are allergic to disopyramide or any ingredients of the medication
• are in shock
• are taking other medications to treat abnormal heart rhythms or medications that may cause abnormal heart rhythms (e.g., amiodarone, quinidine, sotalol, verapamil, diltiazem, pimozide)
• have cardiomyopathy (a disease of the heart muscle)
• have certain severe heart rhythm disorders (i.e., bundle-branch block associated with first-degree AV block, double block, or second- and third-degree AV block with no pacemaker)
• have extensive heart disease
• have glaucoma
• have kidney failure
• have long QT interval
• have severe or uncontrolled congestive heart failure
• have severe sinus node (the heart’s natural pacemaker) dysfunction
• have urinary retention

• Rare occurrence of congestive heart failure (CHF), hypotension, widening QRS, sinus arrest,
  nodal rhythm dissociation, cardiac arrest and cardiovascular collapse have been reported. An
  occasional paradoxical ventricular tachycardia, evolving sometimes to fibrillation has been
  observed. A definite relationship to the drug was not always established in the above
  cardiovascular effects.
• Intra-cardiac conduction abnormalities may occur: QT interval prolongation, atrioventricular
  block and bundle-branch block.
• Other types of arrhythmia have been reported: bradycardia, sinus block.
• The most common adverse reactions which are dose-dependent are associated with the
  anticholinergic properties of the drug. These may be transitory, but may be persistent and can be
  severe. Urinary retention is the most serious anticholinergic effect.
• The following reactions were reported in more than 10% of patients:
  • Anticholinergic: dry mouth (16-30%), urinary retention (7-13%), constipation.
  • Gastrointestinal: nausea, indigestion, vomiting, diarrhea, flatulence, bad taste in the mouth,
    anorexia.
• The following reactions were reported in 1 to 10% of patients:
  • Anticholinergic: blurred vision, dry eyes/nose/throat.
  • Cardiovascular: hypotension with or without CHF, increased CHF, cardiac conduction
    disturbances, proarrhythmic effects (6%), œdema, dyspnea, cyanosis, chest
    pain.
  • Dermatologic: skin reactions including pruritus, urticaria, morbilliform eruption, abdominal
    rash, photosensitization.
  • General: dizziness, vertigo, drowsiness, profuse sweating.
  • Genitourinary: urinary hesitancy and frequency.
  • Other: raised SGOT levels

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breastfeeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Abnormal heart rhythms: Certain medications used to treat abnormal heart rhythms, including disopyramide, can also cause new abnormal heart rhythms, some of which can be life-threatening. Treatment with disopyramide should be started in the hospital, where appropriate monitoring and treatment can be provided.

Certain medications (e.g., sotalol, quinidine, thioridazine, chlorpromazine, droperidol, pimozide, moxifloxacin, mefloquine, pentamidine, arsenic trioxide, probucol, tacrolimus) can increase the risk of a type of abnormal heart rhythm called QT prolongation, and should not be used in combination with disopyramide. If you are taking other medications, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Please refer to the patient leaflet for a comprehensive list of drugs that may interact with RYTHMODAN^®