Brand name: Propafenon
Active ingredient (generic name): Propafenon
Manufacturer: Hexal
Importer: Behestan Darou
Pharmacotherapeutic group: Anti-arrhythmic
Pharmaceutical form: 150mg & 300mg tablets
It has a stabilizing action on myocardial membranes, reduces the fast inward current carried by sodium ions with a reduction in depolarization rate and prolongs the impulse conduction time in the atrium, AV node and primarily, in the His-Purkinje system.
Impulse conduction through accessory pathways, as in WPW syndrome, is either inhibited, by prolongation of the refractory period or blockade of the conduction pathway, both in anterograde but mostly retrograde direction.
At the same time, spontaneous excitability is reduced by an increase of the myocardial stimulus threshold while electrical excitability of the myocardium is decreased by an increase of the ventricular fibrillation threshold.
Pharmacokinetic:
Following oral administration, propafenone is nearly completely absorbed from the gastrointestinal tract in a dose-dependent manner and distributed rapidly in the body.
In the therapeutic concentration range, more than 95% of propafenone is bound to plasma proteins. propafenone is almost exclusively metabolised in the liver. Terminal elimination half-life in patients is 5-7 hours (12 hours in single cases) following repeated doses.
Therapeutic indication:
Arythmol is indicated for the prophylaxis and treatment of ventricular arrhythmias.
Arythmol is also indicated for the prophylaxis and treatment of paroxysmal supraventricular tachyarrhythmias.
Dosage and administration:
Initially, 150 mg three times daily increasing at a minimum of three-day intervals to 300 mg twice daily and if necessary, to a maximum of 300 mg three times daily.
Dosage in impaired liver function: Arythmol is extensively metabolised via a saturable hepatic oxidase pathway. In view of the increased bioavailability and elimination half-life of propafenone, a reduction in the recommended dose may be necessary.
Adverse reaction:
The following adverse events have been reported with this or other formulations of propafenone hydrochloride:
Anorexia, Psychiatric disorders, Anxiety, confusion
Dizziness, headache, syncope, ataxia, restlessness, nightmares, sleep disorders, extrapyramidal symptoms, vertigo, paresthesia, Blurred vision, Nausea, vomiting, constipation, dry mouth, bitter taste, abdominal pain, diarrhoea, bloating,retching
A marked reduction in heart rate (bradycardia) or conduction disorders (i.e. sinoatrial, atrioventricular or intraventricular block) may occur.
Musculoskeletal and connective tissue disorders: Lupus syndrome
Contraindication:
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Known hypersensitivity to propafenone or to any of the other ingredients. Arythmol is contra-indicated in patients with uncontrolled congestive heart failure, cardiogenic shock (unless arrhythmia-induced), severe bradycardia, uncontrolled electrolyte disturbances, severe obstructive pulmonary disease or marked hypotension. Arythmol may worsen myasthenia gravis. Unless patients are adequately paced (see section 4.4, Special Warnings and Precautions for Use), Arythmol should not be used in the presence of sinus node dysfunction, atrial conduction defects, second degree or greater AV block, bundle branch block or distal block. Minor prolongation of the PR interval and intra-ventricular conduction defects (QRS duration of less than 20%) are to be expected during treatment with Arythmol and do not warrant dose reduction or drug withdrawal. Due to the potential for increased plasma concentrations, co-administration of ritonavir and propafenone hydrochloride is contraindicated |
Pharmacokinetic interactions:
The effects of Arythmol may be potentiated if it is given in combination with other local anaesthetic type agents or agents which depress myocardial activity.
Plasma levels of propafenone may be increased by concomitant administration of cimetidine.
Increased propranolol and metoprolol plasma levels have been observed when these beta-blockers were used concurrently with Arythmol.
Coadministration of propafenone hydrochloride with drugs metabolised by CYP2D6 (such as venlafaxine) might lead to increased levels of these drugs.
Drugs that inhibit CYP2D6, CYP1A2 and CYP3A4, e.g. ketoconazole, cimetidine, quinidine, tropisetron, dolasetron, mizolastine, erythromycin and grapefruit juice may lead to increased levels of propafenone hydrochloride. When propafenone hydrochloride is administered with inhibitors of these enzymes, the patients should be closely monitored and the dose adjusted accordingly.
Combination therapy of amiodarone and propafenone hydrochloride can affect conduction and repolarisation and lead to abnormalities that have the potential to be proarrhythmic. Dose adjustments of both compounds based on therapeutic response may be required.
Concomitant use of propafenone and phenobarbital and/or rifampicin (CYP3A4 inducers) may reduce the antiarrythmic efficacy of propafenone as a result of a reduction in propafenone plasma levels.
Special warnings:
In common with other anti-arrhythmic drugs, Arythmol has been shown to alter sensitivity and pacing threshold. In patients with pacemakers, appropriate adjustments may be required.
There is potential for conversion of paroxysmal atrial fibrillation to atrial flutter with accompanying 2:1 or 1:1 conduction block.
Pregnancy and lactation:
Domperidone is divided in group C and it can be administered only if the perceived benefit justifies the potential risks.
Storage temperature:
Room temperature (15-25 C)
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