How does it work?
Tambocor tablets and injection, and Tambocor XL capsules all contain the active ingredient flecainide, which is a type of medicine called an anti-arrhythmic. Flecainide tablets are also available without a brand name, ie as the generic medicine. Flecainide is used to control abnormal heartbeats.
The heart's pumping action is controlled by electrical signals that pass through the heart muscle. The electrical signals cause the two pairs of heart chambers (left and right atria and ventricles) to contract in a regular manner that produces the heartbeat. If the electrical activity in the heart is disturbed for any reason, irregular heartbeats (arrhythmias) of various types can result. These can seriously undermine the pumping action of the heart and result in inefficient blood circulation around the body.
Flecainide helps to treat arrhythmias by decreasing the sensitivity of the heart muscle cells to electrical impulses. This slows and regulates the electrical conduction in the heart muscle, which helps to restore disturbances in the heart rhythm.
Flecainide is used to correct irregular heartbeats and maintain heart rhythms. The medicine will usually be given by injection first, in order to quickly control the heartbeat. The heart rate can then be maintained with the medicine taken by mouth.
What is it used for?
Flecainide is used to control various types of irregular heartbeat including the following:
- Abnormal heart rhythms (arrhythmias) associated with Wolff-Parkinson-White syndrome.
- Rapid heartbeat caused by an additional electrical signal near the AV node (AV nodal reciprocating tachycardia).
- Rapid heartbeat that starts in the lower chambers of the heart and is causing symptoms (symptomatic ventricular tachycardia).
- Irregular heartbeat that only occurs occasionally and is caused by very rapid contraction of the top two chambers of the heart (paroxysmal atrial fibrillation).
How do I take this?
- Tambocor tablets are usually taken twice a day. The dose will vary from person to person and depend on the condition being treated. The tablets can be taken with or without food.
- Tambocor XL capsules are a 'long-acting' or 'modified-release' form of flecainide. This means that they are designed to release the flecainide slowly and continuously over several hours. This produces a steady blood level of the medicine throughout the day.
- Tambocor XL capsules are taken once daily. They can be taken with or without food. The capsules should be swallowed whole, and not opened or chewed, as this would damage the modified-release action.
- Before treatment with this medicine is started your doctor will want you to have a blood test to check your liver and kidney function, so that the correct dose of the medicine can be prescribed. The levels of electrolytes such as sodium, potassium or magnesium in your blood will also be checked and your doctor will correct any problems before starting treatment.
- Most medicines that control abnormal heart rhythms can also provoke them in some circumstances. For this reason, if you feel like your heart condition has got worse, or your heartbeat changes, gets faster or slower, or starts to pound, or you experience chest pain, shortness of breath or feeling faint, it is important to consult your doctor straight away.
Use with caution in
- Elderly people.
- Decreased kidney function.
- Decreased liver function.
- People who have an artificial pacemaker.
- People with heart disease or an enlarged heart.
- People with a sudden onset of irregular heartbeats (atrial fibrillation) following heart surgery.
Not to be used in
- People who have had a heart attack and now have either extra heartbeats that disrupt the normal rhythm of the heart (asymptomatic ventricular ectopics) or occasional short-lived abnormally fast heartbeats (asymptomatic non-sustained ventricular tachycardia).
- Heart failure.
- Heart valve disease affecting the blood circulation.
- Long-term irregular heartbeats (atrial fibrillation) that have not ever been treated.
- People whose irregular heartbeat is related to a problem with the sinus node in their heart (sinus node dysfunction), unless a pacemaker can be used.
- People who have a problem with the heart's electrical message pathways (heart block or atrial conduction defects), unless a pacemaker can be used.
- Children under 12 years old.
This medicine should not be used if you are allergic to any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.
If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Pregnancy and breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
- The safety of this medicine for use during pregnancy has not been established. Seek medical advice from your doctor.
- This medicine passes into breast milk. It is not known to be harmful if used during breastfeeding. However, as with all medicines, you seek medical advice from your doctor before breastfeeding during treatment with this medicine.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.
- Feeling weak or tired.
- Swelling caused by fluid retention (oedema).
- Visual disturbances, such as double vision or blurred vision.
- Shortness of breath.
- Disturbances of the gut such as, nausea, vomiting, abdominal pain, constipation, diarrhoea, indigestion and flatulence.
- Loss of appetite.
- Worsening of heart condition (see warning section above).
- Changes in heart rhythms (see warning section above).
- Yellowing of the skin and whites of the eyes (jaundice) - consult your doctor if you experience this.
- Elevated liver enzymes.
- Skin reactions such as rash, hives or increased sensitivity to sunlight.
- Pins and needles or numb sensations.
- False perceptions of things that are not really there (hallucinations).
- Loss of memory (amnesia).
- Difficulty sleeping (insomnia).
- Shaky movements and unsteady walk (ataxia).
- Inflammation of the lungs (pneumonitis).
- Micro-deposits in the protective outer layer of the eye (corneal microdeposits), which can cause drivers to be dazzled by headlights at night.
The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.
For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
How can this medicine affect other medicines?
It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to make sure that the combination is safe.
The following anti-arrhythmic medicines are not recommended for use with flecainide, as the combination can have an additive effect on slowing down and reducing the contractions of the heart:
There may be an increased risk of the heart beating too slowly if the following medicines are used in combination with flecainide:
- beta-blockers such as atenolol, propranolol
- calcium channel blockers such as verapamil
- other anti-arrhythmic medicines.
There may be an increased risk of irregular heartbeats if the following medicines are used in combination with flecainide:
- the antihistamines mizolastine or terfenadine (these must not be taken with flecainide)
- antipsychotics such as clozapine
- artemether and lumefantrine (Riamet) for malaria
- tricyclic antidepressants such as amitriptyline.
Diuretic medicines such as furosemide, acetazolamide and bendroflumethiazide can sometimes cause the level of potassium in the blood to drop too low. If this happens in someone taking flecainide it can increase the risk of irregular heartbeats. Your doctor will want to check your potassium levels regularly if you are taking a diuretic in combination with flecainide.
Taking this medicine in combination with digoxin can increase the amount of digoxin in the blood. Your doctor may need to monitor your digoxin levels and adjust your dose if necessary.
The following medicines may increase the level of flecainide in the blood and may therefore increase the risk of its side effects:
- amiodarone (your doctor may want to monitor the level of flecainide in your blood if you take it with amiodarone, and reduce your dose as necessary)
- the antimalarial medicine quinine
- protease inhibitors such as ritonavir, lopinavir, indinavir, saquinavir, fosamprenavir (these must not be taken with flecainide because the combination increases the risk of irregular heartbeats)
- selective serotonin re-uptake inhibitor antidepressants (SSRIs) such as fluoxetine.
Other medicines containing the same active ingredient
Flecainide tablets are also available generically (ie without a brand name).