(dye soe peer' a mide)
P : Caution when used during pregnancy
L : Caution when used during lactation
|| See TERMINOLOGY & ABBREVIATIONS ||
In the U.S. National Heart, Lung and Blood Institute's Cardiac Arrhythmia Suppression Trial (CAST), a long-term, multi-center, randomized, double-blind study in patients with asymptomatic non-life-threatening ventricular arrhythmias who had had a myocardial infarction more than 6 days but less than 2 years previously, an excessive mortality or non-fatal cardiac arrest rate (7.7%) was seen in patients treated with encainide or flecainide compared with that seen in patients assigned to carefully matched placebo-treated groups (3.0%). The average duration of treatment with encainide or flecainide in this study was 10 months.The applicability of the CAST results to other populations (e.g., those without recent myocardial infarction) is uncertain. Considering the known proarrhythmic properties of Disopyramide Phosphate and the lack of evidence of improved survival for any antiarrhythmic drug in patients without life-threatening arrhythmias, the use of Disopyramide Phosphate as well as other antiarrhythmic agents should be reserved for patients with life-threatening ventricular arrhythmias.
|Indication(s) & Dosage||Oral route
Supraventricular and ventricular arrhythmias
Adult: 300-800 mg daily in divided doses (as conventional capsules every 6 hr; as extended-release capsules every 12 hr), adjusted according to patient's response.
Child: 12-18 yr: 6-15 mg/kg daily; 4-12 yr: 10-15 mg/kg daily; 1-4 yr: 10-20 mg/kg daily; <1 yr: 10-30 mg/kg daily.
Hepatic impairment: 400 mg daily in divided doses. Liver cirrhosis: consider a therapeutic range 50% lower than in patients with normal hepatic function.
|Administration||May be taken with or without food.
|Overdosage||Symptoms: Anticholinergic side effects, loss of consciousness, hypotension, respiratory arrest, episodes of apnoea, cardiac conduction disturbances, arrhythmias, bradycardia, CHF, asystole and seizures. Management: Fast and aggressive treatment needed even without any symptoms, as it can be fatal. Empty stomach by emesis or gastric lavage. Treatment is supportive with ECG monitoring. Haemodialysis or charcoal haemoperfusion (preferred) may be useful.|
|Contraindications||Patients with complete heart block; glaucoma; predisposition to urinary retention; myasthenia gravis. Sinus node disease in absence of pacemaker. Cardiomyopathy. Cardiogenic shock. Hypotension. Hypersensitivity. Children.|
|Special Precautions||Conduction disorders or uncompensated heart failure. Pregnancy and lactation. Renal and hepatic failure. Family history of glaucoma. Correct potassium deficiency.|
|Adverse Drug Reaction(s)||Impotence, constipation, difficulty in micturition, dry mouth, blurred vision, nausea, bloating, abdominal pain, vomiting, diarrhoea, colic. Psychosis, depression, skin rashes, dizziness, fatigue, muscle weakness, headache, cholestatic jaundice, elevated liver enzymes, thrombocytopenia, agranulocytosis, ventricular tachycardia and fibrillation, heart failure, hypotension, conduction disturbances.
Potentially Fatal: Urinary retention, severe cardiovascular depression if given as rapid IV inj. High risk of recurrence of failure in patients with history of congestive cardiac failure. Negative inotropic effect especially prominent in patients with cardiomyopathy, hypertension and uncompensated cardiac failure.
|Drug Interactions||Avoid other Class I antiarrhythmics and other cardiac depressants including Î²-blockers except in life-threatening arrhythmias. Risk of worsening of arrhythmias, precipitation of new arrhythmias and ventricular fibrillation when used with other anti-arrhythmics. Reduced efficacy when co-admin withphenytoin.
Potentially Fatal: Enhanced antimuscarinic effects with other antimuscarinic drugs. Potentiates negative chronotropic and inotropic effects of Î²-blockers and verapamil. Potentiates inhibitory effect on the conduction system produced by digitalis. Potentiates QT interval prolongation produced by TCAs and amiodarone.
|Pregnancy Category (FDA)||Category C: Either studies in animals have revealed adverse effects on the foetus (teratogenic or embryocidal or other) and there are no controlled studies in women or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the foetus.|
|Storage||Intravenous: Store below 30Â°C. Oral: Store below 30Â°C.|
|Pharmacology||Disopyramide is a Ia antiarrhythmic agent which acts by decreasing myocardial excitability and conduction velocity. It lengthens the effective refractory period of the atrium. It also possesses antimuscarinic and negative inotropic effects.
Absorption: Readily and almost completely absorbed from the GI tract (oral); peak plasma concentrations after 0.5-3 hr.
Distribution: Crosses the placenta and enters the breast milk. Protein-binding: 50-65%.
Metabolism: Hepatic: Partial metabolism; converted to mono-N-dealkylated disopyramide (also has antiarrhythmic and antimuscarinic properties).
Excretion: Mainly in the kidneys via urine (50% as unchanged, 20% as N-dealkylated metabolite and 10% as other metabolites; via the faeces (10% of the dose). 4-10 hr (elimination half-life); may be increased in cardiac failure, renal and hepatic impairment.
|ATC Classification||C01BA03 - disopyramide; Belongs to class Ia antiarrhythmics.|
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|Studies have shown that some antiarrhythmic drugs may increase the risk of death, especially if you have had a previous heart attack. This information also may apply to disopyramide. Disopyramide usually is used only to treat life-threatening arrhythmias.|
Why is Disopyramide prescribed?
Disopyramide is used to treat abnormal heart rhythms (arrhythmias). It works by making your heart more resistant to abnormal activity.
How should Disopyramide be used?
Disopyramide may come as a capsule to take by mouth. Immediate-acting disopyramide may be taken 3 to 4 times a day. The long-acting product is usually taken twice a day. Do not cut, crush, or chew extended-release capsules; swallow them whole.
Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take disopyramide exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
Disopyramide helps control your condition but will not cure it. Continue to take disopyramide even if you feel well. Do not stop taking disopyramide without talking to your doctor.
Other uses for Disopyramide
Disopyramide is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.
What special precautions to follow?Before taking disopyramide,
- tell your doctor and pharmacist if you are allergic to disopyramide or any other drugs.
- tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially clarithromycin, erythromycin, itraconazole, ketoconazole, other medications for arrhythmias such as quinidine or procainamide, phenytoin, potassium supplements, propranolol, verapamil, and vitamins.
- tell your doctor if you 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.
- tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking disopyramide, call your doctor.
talk to your doctor about the risks and benefits of taking disopyramide if you are 65 years of age or older. Older adults should not usually take disopyramide because it is not as safe or effective as other medications that can be used to treat the same condition.
- if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking disopyramide.
- you should know that Disopyramide may make you drowsy. Do not drive a car or operate machinery until you know how Disopyramide affects you.
- remember that alcohol can add to the drowsiness caused by Disopyramide.
- talk to your doctor about the use of cigarettes and caffeine-containing beverages. These products may increase the irritability of your heart and interfere with the action of disopyramide.
What to do if I 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.
What side effects can Disopyramide cause?
Disopyramide may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
dizziness or lightheadedness
stomach pain or bloating
If you experience any of the following symptoms, call your doctor immediately:
swelling of the feet or hands
unusual weight gain
shortness of breath
fever, chills, or sore throat
skin rash or yellowing of the skin
Ref: MedlinePlus, U.S. Natl. Library of Medicine
|| See FDA approved Brand Manufacturer's Prescribing Information |
||| Latest mph edition: 04 Dec 2013 |||| Back to top ||