Tambocor

/ Megapharm

Adults: Supraventicular arrhythmias: the recommended starting dosage is 50 mg twice daily and most patients will be contreolled at this dose. If required the dose may be increased to a maximum of 300 mg daily.
Ventricular arrhytmias: 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 the arrhythmia is required. After 3-5 days it is recommended that the dosage be progressively adjusted to the lowest level which maintains control of the arrhythmia. It may be possible to reduce dosage during long-term treatment.
Children: Flecainide is not recommended in children under 12, as there is insufficient evidence of its use in this age group.
Elderly Patients: The rate of flecainide elimination from plasma may be reduced in elderly people. This should be taken into consideration when making dose adjustments.
Plasma Levels: Based on PVC suppression, it appears that plasma levels of 200-1000 ng/ml may be needed to obtain the maximum therapeutic effect. Plasma levels about 700-1000 ng/ml are associated with increased likelihood of adverse experiences.
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 (or 50 mg twice daily). When used in such patients, frequent plasma level monitoring is strongly recommended. Treatment with oral Tambocor should be under direct hospital or specialist supervision for patients with:
– AV nodal reciprocating tachycardia; arrhytmias associated with Wolff-Parkinson-White Syndrome and similar conditions with accessory pathways.
– Paroxysmal atrial fibrilation in patients with disabling symptoms. Treatment for patients with other indications should continue to be initiated in hospital.

Serious ventricular arrhythmia that have not responded to other drugs, paroxysmal atrial fibrillation; atrial flutter.

Flecainide is contra-indicated in cardiac failure and in patients with a history of myocardial infarction who have either asymptomatic ventricular ectopics or asymptomatic non-sustained ventricular tachycardia. It is also contra-indicated in patients with long standing atrial fibrillation in whom there has been no attempt to convert to sinus rhythm, and in patients with haemodynamically significant valvular heart disease. Unless pacing rescue is available, flecainide 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. Flecainide is contra-indicated in case of hypersensitivity to the active substance of any of excipients.

Electrolyte disturbances should be corrected before using flecainide. 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 is strongly recommended in these circumstances. Flecainide 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 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 voltage 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. 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, arteriosclerotic heart disease and cardiac failure. Flecainide should be avoided in patients with structural organic heart disease or abnormal left ventricular function. Flecainide should be used with caution in patients with acute onset of atrial fibrillation following cardiac surgery. In a large scale, placebo-controlled clinical trial in post-myocardial infarction patients with asymptomatic ventricular arrhythmia, 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. Ventricular proarrhythmic effects in patients with atrial fibrillation/flutter: A review of the world literature revealed reports of 568 patients treated with oral Tambocor for paroxysmal atrial fibrillation/flutter (PAF). Ventricular tachycardia was experienced in 0.4% (2/568) of these patients. Of 19 patients in the literature with chronic atrial fibrillation (CAF), 10.5% (2) experience VT or VF. Flecainide is not recommended for use in patients with chronic atrial fibrillation. Case reports of ventricular proarrhythmic effects in patients treated with Tambocor for atrial fibrillation/flutter have included increased PVCS, VT, Ventricular fibrillation (VF), and death. As with other Class I agents, patients treated with Tambocor for atrial flutter have been reported with 1:1 atrioventricular conduction due to slowing the atrial rate. A paradoxical increase in the ventricular rate also may occur in patients with atrial fibrillation who receive Tambocor. Concomitant negative chronotropic therapy such as digoxin or beta-blockers may lower the risk of this complication.

Asthenia, fatigue, fever, edema. AV block-second degree and third degree, bradycardia, cardiac failure/congestive cardiac failure, chest pain, hypotension, myocardial infarction, palpilation, sinus pause or arrest and tachycardia. A range of allergic skin reactions have been reported. Reductions in red blood cells, white blood cells and platelets have been occasionally reported. Rarely, hallucinations, depression, confusion, anxiety and amnesia have been reported. Nausea and vomiting. Giddiness, dizziness and lightheadedness which are usually transient. Dyspnoea and rare cases of pneumonitis have been reported. For full details see prescribing information.

Other class 1 antiarrhythmics, cardiac glycosides, thiazide and loop diuretics. Calcium antagonists, beta-blockers, cimetidine, barbiturates, phenytoin, carbamazepine, acetazolamide.
For full details see prescribing information.

Pregnancy: 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.
Lactation: 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.

Overdose with flecainide is a potentially life threatening medical emergency. 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 conduction disturbances or the patient’s left ventricular function is otherwise compromised.