Disopyramide-antiarrhythmic drug and its pharmacology

Description:-

A class I anti-arrhythmic agent (one that interferes directly with the depolarization of the cardiac membrane and thus serves as a membrane-stabilizing agent) with a depressant action on the heart similar to that of guanidine. It also possesses some anticholinergic and local anesthetic properties.

This compound belongs to the class of organic compounds known as pheniramines. These are compounds containing a pheniramine moiety, which is structurally characterized by the presence of a 2-benzylpyridine linked to an dimethyl(propyl)amine to form a dimethyl[3-phenyl-3-(pyridin-2-yl)propyl]amine skeleton.

Pharmacodynamics

Disopyramide is an antiarrhythmic drug indicated for the treatment of documented ventricular arrhythmias, such as sustained ventricular tachycardia that are life-threatening. In man, Disopyramide at therapeutic plasma levels shortens the sinus node recovery time, lengthens the effective refractory period of the atrium, and has a minimal effect on the effective refractory period of the AV node. Little effect has been shown on AV-nodal and His-Purkinje conduction times or QRS duration. However, prolongation of conduction in accessory pathways occurs.

 Pharmacokinetics:-

Absorption:- Nearly complete

Protein binding:- 50%-65%

Metabolism:- Hepatic

Half life 6.7 hours (range 4-10 hours)

Drug Interactions

1. Acarbose + disopyramide = Acarbose may increase the hypoglycemic activities of Disopyramide.

2. Acebutolol + disopyramide = Disopyramide may increase the bradycardic activities of Acebutolol.

3. Acetohexamide + disopyramide = Acetohexamide may increase the hypoglycemic activities of Disopyramide.

4. Acetylsalicylic acid + disopyramide = Acetylsalicylic acid may increase the hypoglycemic activities of Disopyramide.

5. Aicar + disopyramide = Aicar may increase the hypoglycemic activities of Disopyramide.

6. Alfuzosin + disopyramide = Alfuzosin may increase the QTc-prolonging activities of Disopyramide.

7. Alogliptin + disopyramide =Alogliptin may increase the hypoglycemic activities of Disopyramide.

8. Alprenolol + disopyramide = Disopyramide may increase the bradycardic activities of Alprenolol.

9. Amantadine + disopyramide = Amantadine may increase the QTc-prolonging activities of Disopyramide.

Side effects:-

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

 Therapeutic Uses:-

This medication is used to treat certain types of serious (possibly fatal) irregular heartbeat, such as persistent ventricular tachycardia. It is used to restore normal heart rhythm and maintain a regular, steady heartbeat. Disopyramide is known as an anti-arrhythmic drug. It works by blocking certain electrical signals in the heart that can cause an irregular heartbeat. Treating an irregular heartbeat can decrease the risk for blood clots, and this effect can reduce your risk of heart attack or stroke.

REFERENCE:-Tripathi K D"Essential of medical pharmacology",7th edition ,page no-528,529,531,537,538