Disopyramide Pharmacology


About Disopyramide
Class Ia Antiarrhythmic Agent, Pyridine derivative, anti-muscarinic, Anti-arrhythmic.
Mechanism of Action of Disopyramide
Disopyramide is a class-1 antiarrhythmic agent. It blocks myocardial Na+ channels in an open state, reduces automaticity, and maximal rate of 0 phase depolarization. It prolongs action potential duration (APD) due to K+ channel blockade and lengthens Effective refractory period (ERP) by its moderate effect on recovery of Na+ and K+ channels. It reduces availability of Na+ channels as well as delays their activation. It increases threshold for excitation. ERP is prolonged more than APD so that ERP/APD is increased. It decreases myocardial excitability and conduction velocity and may depress myocardial contractility. It also posses anticholinergic activity; which modifies its direct myocardial effects. It reduces conduction velocity in the atria, ventricles, and His-Purkinje system. It prolongs ERP and increase AV node conductivity. It suppresses automaticity in His- Purkinje system ectopic pacemakers. It prolongs QT interval.
Pharmacokinets of Disopyramide
Absorption: Well absorbed orally.
Distribution: Widely distributed in to the extra cellular fluid.
Metabolism: Partially metabolized in liver by dealkylation.
Excretion: Excreted through urine mostly as unchanged drug rest as metabolites.
Onset of Action for Disopyramide
30 to 60 minutes
Duration of Action for Disopyramide
6 to 7 hours
Half Life of Disopyramide
6 to 8 hours
Side Effects of Disopyramide
1. Dry mouth
2. Constipation
3. Urinary retention
4. Blurred vision
5. Hypotension
6. Heart failure
7. Heart block
8. Oedema
9. Arrhythmias
10. Shortness of breath
11. Chest pain
12. Dizziness
13. Agitation
14. Fatigue
15. Weakness
16. Syncope
17. Cholestatic jaundice
18. Rashes
19. Pruritus
20. Muscle pain

Contra-indications of Disopyramide
1. Hypersensitivity to the drug
2. Cardiogenic shock
3. Complete Second or third degree Heart block
4. Sinus node diseases
5. Cardiomyopathy
6. Hypotensive state
7. Prostate hypertrophy
8. Cardiac failure

Special Precautions while taking Disopyramide
1. Renal impairment
2. Hepatic impairment
3. Congestive heart failure
4. Conduction abnormalities
5. Myasthenia gravis
6. Glaucoma
7. Digitalis intoxication
8. History of embolism
9. Sinus Bradycardia
10. Muscle weakness
Pregnancy Related Information
Old Age Related Information
Use with caution
Breast Feeding Related Information
Children Related Information
Use with caution
Indications for Disopyramide
1. Atrial fibrillation
2. Atrial flutter
3. Paroxysmal supraventricular tachycardia
4. Atrial arrhythmia
5. Ventricular premature contractions
6. Premature atrial contractions
7. Ventricular tachycardia
8. Arrhythmia associated with Wolff Parkinson White syndrome

Interactions for Disopyramide
Anti-arrhythmics: Avoid other antiarrhythmics except in life threatening conditions.
Beta Blockers & Verapamil: Adverse negative chronotopic and inotropic effects potentiated.
Erythromycin: Efficacy of disopyramide enhanced leading to arrhythmias and increased QT intervals.
Quinidine: Increased disopyramide serum levels leading to toxicity and decreased quinidine levels resulting in reduced efficacy.
Rifampicin: Decreases serum levels of disopyramide.
Digoxin: Potentiates inhibitory effect on conduction system produced by digitalis.
Hydantoin: Efficacy of disopyramide reduced upto several days after withdrawal of hydantoin. Anticholinergic effects may be enhanced.
Typical Dosage for Disopyramide
Initially 200 to 300mg loading dose; proportionate to bodyweight. Then 100 to 150mg; four times daily. Or 300mg twice daily.
Maximum dose: 800mg in three to four divided doses.
Children (age 12 to 18): 6 to15mg/kg/day.
Children (age 4 to 12): 10 to15mg/kg/day.
Children (age 1 to 4): 10 to 20mg/kg/day.
Children (younger than 1): 10 to 30mg/kg/day.
Schedule of Disopyramide
Storage Requirements for Disopyramide
Store at room temperature in a well closed container and protects from moisture, heat and light. Keep out of reach of children.
Effects of Missed Dosage of Disopyramide
Effects of Overdose of Disopyramide
Treatment is supportive and symptomatic. If ingestion was recent remove drug from the body by induced emesis, gastric lavage. Absorption is reduced by administration of activated charcoal. Acidification of urine enhance elimination,. Monitor and support cardiovascular and respiratory functions with haemodynamic and ECG monitoring. Reverse hypotension using isoproterenol or dopamine after adequate hydration. Digoxin and diuretics are administered to treat heart failure. Haemodialysis and charcoal haemoperfusion may remove drug from the body. Some patients may require intra-aortic balloon counterpulsation, mechanically assisted respiration or endocardial pacing.

Home Delivery for Disopyramide in Your City

Medicine India is just a publishing medium for medicine related information and does not provide services or sales of medicines including disopyramide.

However, we do publish a comprehensive directory of Pharmacies, Chemists and Druggists in cities all over India. You can use this directory to find the medicine stores in your city (or area) that provide home delivery services for disopyramide and other medicines and health products. Home delivery services for disopyramide may be free or they may cost you depending on the pharmacy and the minimum order requirements. It would be best to get this clarified while placing the order.

Please be aware that you should take disopyramide only if a doctor has recommended or prescribed it. Some or all pharmacies who provide a home delivery service for medicines might insist on a prescription for disopyramide before they complete the sale. You can get this information while placing the order for disopyramide with the pharmacy.

Disopyramide is a generic medicine name and there are several brands available for it. Some of the brands for disopyramide might be better known than disopyramide itself. If the pharmacy that's willing to deliver medicines to your home doesn't have disopyramide in stock, you can ask for one of the branded alternatives for disopyramide.