Procainamide Pharmacology

Procainamide

About Procainamide
Sodium (Na+) channel blocker, Antiarrhythmic (Class Ia),local or regional anesthetic.
Mechanism of Action of Procainamide
Procainamide 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 block 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 APD in atria, ventricles and His-Purkinje system. It shortens ERP of AV node. Anticholinergic action of the drug also increases AVnode conductivity. It suppresses automaticity in His- Purkinje system ectopic pacemakers. It prolongs PR and QT interval. It also exerts peripheral vasodilatory effect.
Pharmacokinets of Procainamide
Absorption: Well absorbed orally. Distribution: Widely distributed in to the tissues. Metabolism: Metabolized in liver primarily by acetylation to N-acetyl Procainamide; which blocks K+ channels and prolongs repolarisation. Excretion: Excreted through urine both as metabolites and as unchanged drug.
Onset of Action for Procainamide
30 to 60 minutes.
Duration of Action for Procainamide
Below 3 years
Half Life of Procainamide
2 to 6 hours
Side Effects of Procainamide
1.Nausea
2.Vomiting
3.Anorexia
4.Diarrhoea
5.Bitter taste
6.Mood changes
7.Confusion
8.Hallucinations
9.Arrhythmias
10.Prolongs Q-T intervals
11.Hypotension
12.Ventricular asystole
13.Bradycardia
14.AV block
15.Ventricular fibrillation
16.Fever
17.Angioedema
18.Thrombocytopenia
19.Agranulocytosis
20.Allergic manifestations
21.Elevated liver function tests
22.Renal impairment
23.Systemic lupus erythematosus like syndrome
24.False positive results for Anti Nuclear Antibody tests
Contra-indications of Procainamide
1.Hypersensitivity to the drug
2.Complete, Second, or third degree Heart block
3.Long Q-T interval
4.Myasthenia gravis
5.Systemic lupus erythematosus

Special Precautions while taking Procainamide
1.Renal impairment
2.Hepatic impairment
3.Congestive heart failure
4.Hypotensive state
5.Digitalis intoxication
6.History of embolism
7.Sinus Bradycardia
8.Blood dyscrasia
9.Bone marrow suppression
10.Muscle weakness
11.Infection accompanied by fever because hypersensitivity reactions are masked

Pregnancy Related Information
Use with caution
Old Age Related Information
Use with caution
Breast Feeding Related Information
Use with caution
Children Related Information
Use with caution
Indications for Procainamide
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 Procainamide
N/A
Typical Dosage for Procainamide
Oral: 50mg/kg/day in divided doses at every 3 to 6 hours. Increases the dosage if required until arrhythmias disappear, adverse effects develop, or 500mg has been given.
I.V.: 50 to 100mg every 5 minutes by slow I.V. rate not more than 25 to 50mg/minute;
Until arrhythmias disappear, adverse effects develop, or 500mg has been given. When arrhythmias disappear; give continuous infusion of 1 to 6mg/minute.If arrhythmias reoccur repeat bolus as above and increase infusion rate.
Maximum dose: 1gm.
Children: Oral: 40 to 60mg/kg/day in four to six divided doses.
I.V.: 3 to 6mg/kg over 5 minutes; followed by 0.02 to 0.08mg/kg/minute.

Schedule of Procainamide
H
Storage Requirements for Procainamide
Store at controlled room temperature at a range of 15 to 25 degree C. in a well closed container and protects from moisture.
Effects of Missed Dosage of Procainamide
Take the missed dose as soon as noticed and if it is the time for next dose then skip the missed dose. Continue the regular schedule. Do not double the dose.
Effects of Overdose of Procainamide
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 phenylephrine or nor epinephrine after adequate hydration. Perform cardiac pacing if required. Treat altered Q-T interval with isoproterinol or ventricular pacing. I.V. infusion of 1/6 sodium lactate solution reduces cardiotoxic effect of drug. Haemodialysis may be effective in removing drug and metabolite.

Home Delivery for Procainamide in Your City

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

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 procainamide and other medicines and health products. Home delivery services for procainamide 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 procainamide 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 procainamide before they complete the sale. You can get this information while placing the order for procainamide with the pharmacy.

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