Tambocor (Flecainide 50mg) Tablets

Tambocor general information

What is Tambocor?

Tambocor tablets 50mg contain flecainide, a medication that is used to control irregular or uneven heartbeat.  This condition is known as arrhythmia, and it increases the risk of stroke, heart failure and heart attack.  Tambocor is only used for severe arrhythmias, and only if symptoms cannot be controlled by other treatments or if you are unable to tolerate other medications.

The heart has two chambers, the lower ventricles, and the upper atria.  They usually beat in a coordinated, regular and steady rhythm.  This keeps blood pumping out of the heart to the rest of the body and allows it to fill again.  The heartbeat is controlled by the heart’s own electrical circuit. Any failure of this electrical system results in random or uncoordinated beating between the chambers of the heart, which is the cause of the arrhythmia. 

There are several arrhythmia types, and atrial fibrillation is the most common heart rhythm disorder, where the abnormal rhythm begins in the upper chambers of the heart.  Atrial fibrillation symptoms include feeling a sensation of fluttering in the chest, palpitations, shortness of breath, and extreme tiredness or fatigue.  You may also have a rapid heartbeat (tachycardia), extra heartbeat or a missed heartbeat.  Atrial flutter is another form of atrial arrhythmia and is when the atrial chambers beat regularly but faster and more often than the ventricles.  Both of these are also called supraventricular arrhythmia.  Tambocor tablets 50mg are used to treat paroxysmal fibrillation, which means that it happens in short episodes and symptoms can begin suddenly and then stop abruptly.  This is different from chronic arrhythmia that continues for some time.  Arrhythmia can start when you exert yourself, or it can happen when at rest so that it is unpredictable. 

Ventricular arrhythmia is the result of abnormal electrical impulses that originate in the ventricular chambers.  It is caused by rapid, irregular contraction of the ventricles, which prevents oxygen-rich blood from circulating efficiently to the heart itself and the rest of the body.  This increases the workload on the heart and its need for oxygen, and can result in restriction of oxygen to the tissues (ischemia) and heart attack.  This can become a serious and life-threatening condition.  Symptoms include pain in the chest and a rapid heartbeat (tachycardia).  Tambocor tablets 50mg are only used for severe and sustained ventricular arrhythmia.

How does Tambocor work?

Flecainide in Tambocor tablets 50mg belongs to a group of drugs known as the Class I antiarrhythmics, and it works by correcting the misfiring of electrical impulses in the heart. 

The heart has a specialised electrical system composed of three main parts.  The sinoatrial node in the walls of the upper right-hand atrial chamber is the heart’s natural pacemaker, and this spontaneously generates an electrical signal called the action potential.  This signal is transmitted to the atrioventricular node, which conducts electrical impulses between the atrial and ventricular chambers of the heart.  More specialised cells called the left and right bundle of His and the Purkinje fibres transmit electrical signals around the heart.  The rate at which the heart beats depends on the speed that the action potential is produced, which determines how fast the heart muscle cells (cardiac myocytes) contract. 

The electrical signal generated by the atrioventricular node stimulates atrial cells to contract, pushing blood into the ventricles.  The signal is then distributed to the ventricles, causing them to contract, pushing blood out of the heart and into the lungs and out to the rest of the body.  Between each muscle contraction is a rest phase, which is when the heart fills up with blood.

Contraction of heart muscle cells depends on the movement of ions into and out of the cells, which is called depolarisation and repolarisation.  QT interval is used to measure the electrical activity of the heart muscle and includes depolarisation and repolarisation.

Flecainide is a sodium channel blocker, which means that it stops the flow of sodium ions into the cells, through gaps in the heart muscle cell membrane called sodium channels.  This increases the QT interval and extends the rest phase of the heart muscle between contractions, which slows down the contraction of heart muscle cells, stabilises abnormal rhythms of the heart and restores rhythm control. 

Tambocor tablets 50mg are formulated for immediate release, which means that flecainide is released as soon as you have swallowed the tablet and enters the circulation rapidly.  However, flecainide reaches peak blood concentration after 6 hours and then drops, which is why you need to take your Tambocor tablets 50mg twice daily.

What does Tambocor contain?

Tambocor tablets 50mg contain the active ingredient flecainide, an antiarrhythmic used to treat irregular heartbeat.  They also contain croscarmellose sodium hydrogenated vegetable oil magnesium stearate microcrystalline cellulose pregelatinised maize starch.

What are the side effects of Tambocor?

Most medications have some side effects, but they are not experienced by everyone.  Some side effects are commonly experienced when taking Tambocor tablets 50mg and these include feeling dizzy, double vision, blurred vision, feeling weak and lacking in energy, feeling hot (pyrexia) and oedema (fluid in the tissues).

When should Tambocor not be used?

Have a talk with your primary healthcare physician before taking Tambocor tablets 50mg so that you have a full understanding of what this medicine is for and how to use it.  There are some reasons for not taking a medication; these are called contraindications, and you should consider the following before taking Tambocor:

• Have you ever had a reaction or an allergy when taking Tambocor?
• Are pregnant or are breastfeeding?
• Do you have any disease of the kidneys or liver?
• Have you ever had a heart attack, congestive heart failure or heart valve disease?
• Do you have a pacemaker?
• Do you have severe bradycardia (slow heart rate) or hypotension (low blood pressure)?
• Do you have chronic atrial fibrillation, which is arrhythmia that continues over time?

What medications interact with Tambocor?

Some medicines interact with Tambocor tablets 50mg and may affect the way it works, be affected by Tambocor, or increase side effects.  You should discuss possible flecainide interactions with your primary care physician, who may advise that you do not take them or adjust the dose you take. 

These interactions may include: other antiarrhythmics that work in the same way, beta blockers like propranolol for high blood pressure, digoxin for heart problems, calcium channel blockers like diltiazem and verapamil for high blood pressure, anti-psychotics like pimozide, anti-depressants like amitriptyline and fluoxetine, antihistamines like terfenadine, antivirals like ritonavir for HIV, antiepileptics like phenytoin and carbamazepine, antimalarials like quinine, cimetidine for stomach ulcers, quit smoking aids like bupropion.

If other medications may interact with Tambocor, your doctor will discuss these with you. 

How should Tambocor be used and for how long?

You should take your Tambocor tablets 50mg swallowed whole with a glass of water, on an empty stomach or at least one hour before a meal, as food may affect how Tambocor is absorbed.  The dose you take should be as recommended by your doctor.  The usual starting dose is one tablet twice daily but your doctor may increase your dosage, depending on how you respond and how it affects you.  You should continue to take your Tambocor tablets 50mg for as long as recommended by your doctor, which may be several weeks or longer.

Missed dose of Tambocor

If you miss a dose of Tambocor tablets 50mg take it as soon as you remember, unless it is time to take the next dose, then skip the missed dose.  Do not take a double dose.

How should Tambocor be stored?

You should store your Tambocor tablets 50mg below 25°C in a cool dry place.