Each tablet contains flecainide acetate 100 mg.
Flecainide acetate (Tambocor) is a Class 1 anti-arrhythmic (local anaesthetic) agent for the treatment of the conditions listed in Indications when these are resistant to other therapy or when other treatment is unsatisfactory. It is recommended that treatment with Flecainide acetate (Tambocor) should be initiated in hospitals.
Flecainide acetate (Tambocor) slows conduction through the heart, having its greatest effect on His-bundle conduction. It also acts selectively to increase anterograde and particularly retrograde accessory pathway refractoriness. Its actions may be reflected in the ECG by prolongation of the PR interval and widening of the QRS complex. The effect on the JT interval is insignificant at therapeutic levels.
Flecainide acetate (Tambocor) tablets are indicated for: Paroxysmal supraventricular tachycardias, including atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia and other supraventricular tachycardias of unspecified mechanism.
Paroxysmal atrial fibrillation/flutter.
Symptomatic sustained ventricular tachycardia.
Premature ventricular contractions and/or non-sustained ventricular tachycardia which are causing disabling symptoms.
Adults: Ventricular arrhythmias: the recommended starting dosage is 100 mg twice daily. The maximum daily dose is 400 mg and this is normally reserved for patients of large build or where rapid control of arrhythmia is required. After 3-5 days it is recommended that the dosage be progressively adjusted to the lowest level which maintains control of arrhythmia.
It may be possible to reduce dosage during long-term treatment.
Supraventricular arrhythmias: the recommended starting dosage is 50 mg twice daily and most patients will be controlled at this dose. If required, the dose maybe increased to a maximum of 300 mg daily.
Children: Flecainide acetate (Tambocor) is not recommended in children under 12, as there is no evidence of its use in this age group.
Elderly patients: The rate of flecainide elimination from plasma may be reduced in elderly people. An initial dose of one tablet twice daily will usually be adequate, and it may well be possible to reduce this dose for maintenance therapy after one week.
Dosage in impaired renal function: In patients with significant renal impairment (creatinine clearance of 35 mL/min./1.73 sq. m. or less) the maximum initial dosage should be 100 mg daily. When used in such patients, frequent plasma level monitoring is strongly recommended.
No specific antidote is known. There is no known way of rapidly removing flecainide from the system, but forced acid diuresis may theoretically be helpful.
Neither dialysis nor haemoperfusion is helpful and injections of anticholinergics are not recommended.
Treatment may include therapy with an inotropic agent, intravenous calcium, giving circulatory assistance (e.g. balloon pumping), mechanically assisting respiration, or temporarily inserting a transvenous pacemaker if there are severe disturbances or the patient's left ventricular function is otherwise compromised.
In cardiac failure.
Unless pacing rescue is available, Flecainide acetate (Tambocor) should not be given to patients with sinus node dysfunction, atrial conduction defects, second degree or greater atrioventricular block, bundle branch block or distal block.
Asymptomatic premature ventricular contractions and/or asymptomatic non-sustained ventricular tachycardia in patients with a history of myocardial infarction.
In a large scale, placebo-controlled clinical trial in post-myocardial infarction patients with asymptomatic ventricular arrhythmias, oral flecainide was associated with a 2.2 fold higher incidence of mortality or non-fatal cardiac arrest as compared with its matching placebo. In that same study, an even higher incidence of mortality was observed in flecainide-treated patients with more than one myocardial infarction. Comparable placebo-controlled clinical trials have not been done to determine if flecainide is associated with higher risk of mortality in other patient groups.
Electrolyte disturbances should be corrected before using Flecainide acetate (Tambocor). Since flecainide elimination from the plasma can be markedly slower, in patients with significant hepatic impairment, flecainide should not be used in such patients unless the potential benefits clearly outweigh the risks.
Plasma level monitoring strongly recommended in these circumstances.
Flecainide acetate (Tambocor) is known to increase endocardial pacing thresholds - i.e. to decrease endocardial pacing sensitivity. This effect is reversible and is more marked on the acute pacing threshold than on the chronic.
Flecainide acetate (Tambocor) should thus be used with caution in all patients with permanent pacemakers or temporary pacing electrodes, and should not be administered to patients with existing poor thresholds or non-programmable pacemakers unless suitable pacing rescue is available.
Generally, a doubling of either pulse width or current is sufficient to regain capture, but it may be difficult to obtain ventricular thresholds less than 1 volt at initial implantation in the presence of Flecainide acetate (Tambocor).
The minor negative inotropic effect of flecainide may assume importance in patients predisposed to cardiac failure.
Difficulty has been experienced in defibrillating some patients. Most of the cases reported had pre-existing heart disease with cardiac enlargement, a history of myocardial infarction, arterio-sclerotic heart disease and cardiac failure.
Concomitant antiarrhythmic therapy. Due to limited exposure, the concomitant use of Tambocor and other antiarrhythmic agents is not recommended.
Both disopyramide and verapamil have negative inotropic properties and the effects of coadministration with Tambocor are unknown. Neither disopyramide nor verapamil should be administered concurrently with Tambocor unless, in the judgment of the doctor, the benefit of this combination outweighs the risk.
Formal interaction studies have not been conducted with amiodarone and Tambocor. However clinical experience indicates, as for many other antiarrhythmic agents, that amiodarone can increase plasma levels of flecainide.
If, in the judgment of the doctor, the benefits outweigh the risks and Tambocor is to be administered in the presence of amiodarone, the dose of Tambocor should be reduced with plasma flecainide monitoring.
Lignocaine has been used occasionally with Tambocor while awaiting the therapeutic effect of Tambocor. No adverse drug interactions were apparent.
However, no studies have been performed to demonstrate the usefulness of this regimen.
Recommendations for initiation of treatment: For patients with paroxysmal supraventricular arrhythmias, oral flecainide therapy may be started on an outpatient basis.
For patients with symptomatic sustained ventricular tachycardia, oral flecainide therapy should be started in the hospital.
For patients with premature ventricular contractions and/or non-sustained ventricular tachycardia causing disabling symptoms, a decision regarding outpatient or inpatient initiation of oral flecainide therapy must be based upon the physician's assessment of the individual patient.
There is no evidence as to drug safety in human pregnancy.
In New Zealand White rabbits high doses of flecainide caused some foetal abnormalities, but these effects were not seen in Dutch Belted rabbits or rats. The relevance of these findings to humans has not been established. Data have shown that Flecainide crosses the placenta to the foetus in patients taking Flecainide during pregnancy.
Flecainide is excreted in human milk and appears in concentrations which reflect those in maternal blood.
The risk of adverse effects to the nursing infant is very small.
The benefit of TAMBOCOR during lactation should therefore be weighed against the possible effects on the child.
Most commonly giddiness, dizziness and lightheadedness.
Visual disturbances, such as double vision and blurring of vision, may occur. More rarely nausea and vomiting have been reported. These effects are usually transient and disappear upon continuing or reducing the dosage.
Pro-arrhythmic effects have been reported in a small number of patients.
A few cases of elevated liver enzymes and jaundice have been reported which were possibly related to treatment with Flecainide acetate (Tambocor).
During long term therapy a few cases of peripheral neuropathy, parathesia and ataxia have been reported.
Extremely rare cases of corneal deposits, pulmonary fibrosis, interstitial lung disease and pneumonitis have also been reported.
Use of flecainide with other sodium channel blockers is not recommended.
Treatment with Tambocor is compatible with use of oral anti-coagulants.
Flecainide can cause the plasma digoxin level rise by about 15%, which is unlikely to be of clinical significance for patients with plasma levels in the therapeutic range.
It is recommended that the digoxin plasma level in digitalised patients should be measured not less than six hours after any digoxin dose, before or after administration of flecainide.
The possibility of additive negative inotrophic effects of beta blockers and other cardiac depressants with flecainide should be recognised.
Limited data in patients receiving known enzyme inducers (phenytoin, phenobarbital, carbamazepine) indicate only 30% increase in the rate of flecainide elimination.
In healthy subjects receiving cimetidine (1 g daily) for one week, plasma flecainide levels increased by about 30% and the half life increased by 10%.
When flecainide is given in the presence of amiodarone, the usual flecainide dosage should be reduced by 50% and the patient monitored closely for adverse effects.
Plasma level monitoring is strongly recommended in these circumstances.
Store at a temperature not exceeding 30°C.
Shelf-life: 3 years.
C01BC04 - flecainide ; Belongs to class Ic antiarrhythmics.