Special Warning : אזהרת שימוש

4.4 Special warnings and precautions for use

Intravenous treatment with flecainide acetate should be initiated in hospital. Treatment for patients with other indications should continue to be initiated in hospital.

Treatment with oral Tambocor tablets should be under direct hospital or specialist supervision for patients with:
• AV nodal reciprocating tachycardia; arrhythmias associated with Wolff-Parkinson- White Syndrome and similar conditions with accessory pathways.

• Paroxysmal atrial fibrillation in patients with disabling symptoms.

Continuous ECG monitoring is recommended in all patients receiving bolus injection.

Tambocor tablets, like other antiarrhythmics, may cause proarrhythmic effects, i.e. it may cause the appearance of a more severe type of arrhythmia, increase the frequency of an existing arrhythmia or the severity of the symptoms (see section 4.8).

Tambocor tablets should be avoided in patients with structural heart disease or abnormal left ventricular function (see section 4.8).

Tambocor tablets should be used with caution in patients with acute onset of atrial fibrillation following cardiac surgery.

Tambocor tablets has a selective effect that increases the refractory period of the anterograde,and especially, the retrograde pathways. Tambocor tablets prolongs the QT interval and widens the QRS complex by 12-20 %. The effect on the JT interval is insignificant. Nevertheless, there have been reports of prolongation of the JT interval of up to 4%. This action is less marked than that observed with the class 1a antiarrhythmic drugs however.

A Brugada syndrome may be unmasked due to Tambocor tablets therapy. In the case of development of ECG changes during treatment with Tambocor tablets that may indicate Brugada syndrome, consideration to discontinue the treatment should be made.

Since Tambocor tablets elimination from the plasma can be markedly slower in patients with significant hepatic impairment, Tambocor tablets should not be used in such patients unless the potential benefits clearly outweigh the risks. Plasma level monitoring is strongly recommended in these circumstances.

Tambocor tablets should be used with caution in patients with impaired renal function (creatinine clearance ≤ 35 ml/min/1.73 m2) and therapeutic drug monitoring is recommended as increase of plasma levels may also result from renal impairment due to a reduced clearance of Tambocor tables.

The rate of Tambocor tablets elimination from plasma may be reduced in the elderly.
This should be taken into consideration when making dose adjustments.

Tambocor tablets is not recommended in children under 12 years of age, as there is insufficient evidence of its use in this age group (see section 4.2)

Electrolyte disturbances (e.g. hypo- and hyperkalaemia) should be corrected before using Tambocor tablets. (see section 4.5 for some drugs causing electrolyte disturbances).

Severe bradycardia or pronounced hypotension should be corrected before using Tambocor tablets.

Tambocor tablets is known to increase endocardial pacing thresholds - ie to decrease endocardial pacing sensitivity. This effect is reversible and is more marked on the acute pacing threshold than on the chronic. Tambocor tablets 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.

Tambocor tablets should be used with caution in patients with ”sick sinus syndrome”.

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 Tambocor tablets.

The minor negative inotropic effect of Tambocor Tablets 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.

Tambocor tablets has been shown to increase mortality risk of post-myocardial infarction patients with asymptomatic ventricular arrhythmia.

In a large scale, placebo-controlled clinical trial; in post-myocardial infarction patients with asymptomatic ventricular arrhythmia, oral Tambocor tablets 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 Tambocor tablets -treated patients with more than one myocardial infarction. Comparable placebo-controlled clinical trials have not been done to determine if Tambocor tablets is associated with higher risk of mortality in other patient groups.

Dairy products (milk, infant formula and possibly yoghurt) may reduce the absorption of Tambocor tablets in children and infants. Tambocor tablets is not approved for use in children below the age of 12 years, however Tambocor tablets toxicity has been reported during treatment with Tambocor tablets in children who reduced their intake of milk, and in infants who were switched from milk formula to dextrose feedings.

Tambocor tablets as a narrow therapeutic index drug requires caution and close monitoring when switching a patient to a different formulation.

This medicinal product contains less than 1 mmol sodium (23 mg) per tablet, that is to say essentially ‘sodium-free’.

For further warnings and precautions please refer to section 4.5.

Effects on Driving

4.7 Effects on ability to drive and use machines

Undesirable effects such as dizziness and visual disturbances have been reported.
These effects are usually transient. However, if these undesirable effects are experienced then driving ability, operation of machinery and work without a secure fit may be affected.