Aratac general information
What is Aratac used for?
If you feel your pulse by placing a finger on your wrist, you should feel a nice steady heartbeat that indicates a regular heart rhythm. This means that your heart is pumping by synchronised contraction of the heart muscle. The heart rate is the number of times your heart beats per minute and is usually 60-100 beats when you are at rest. Arrhythmia is a heart rhythm disorder that causes an irregular heartbeat and an increased heart rate. It is caused by abnormal electrical signals being transmitted around the heart in a disorganised manner. Aratac tablets 100mg are used to treat tachyarrhythmia, which is tachycardia (rapid heartbeat) due to abnormal heart rhythm (arrhythmia), and Aratac 100 is used only when other treatments have not worked or are contraindicated and cannot be used.
Electrical activity of the heartbeat
The heartbeat is controlled by a complex electrical system that connects the upper chambers of the heart, the atria, and the lower chambers, the ventricles. An electrical signal is automatically generated from an area of the heart called the atrioventricular (AV) node in the upper chambers or atria also known as the heart’s pacemaker, and this signal causes the muscle cells (myocytes) in the atria to contract, which forces blood into the ventricles. This electrical impulse is then transmitted to the Sinoatrial (SA) node in the ventricles, which then contract, forcing blood out to lungs (right ventricle) or the rest of the body (left ventricle). The signal fades, and another is immediately generated to start the heartbeat cycle over again.
Atrial fibrillation and flutter
Atrial fibrillation (AF) is the most common form of arrhythmia and is caused by electrical signals generated in the AV node firing off erratically, which makes the atrial cells beat unevenly instead of in unison, and also too fast. This irregular signal is transmitted to the ventricular cells and they cannot contract as fast as the atrial cells so that coordination between the upper and lower chambers is lost. Also, the atria cannot empty entirely of blood, causing blood to pool and with it a risk that a blood clot can form. Although not usually life-threatening, this increases the risk of heart attack and stroke. Atrial fibrillation can be stimulated as a one-off such as by intense activity or excess alcohol consumption, or it can happen in repeated episodes known as paroxysmal. If it continues, this is known as chronic AF and is usually caused by heart disease or another health condition.
Atrial flutter is another type of supraventricular tachycardia (rapid heartbeat initiated above the ventricle) when the atrial chambers beat regularly but faster and more often than the ventricles.
Ventricular arrhythmia and fibrillation
In ventricular arrhythmia, the abnormal electrical impulse originates in the lower (ventricular) chambers of the heart and is caused by the ventricles contracting too fast. The ventricles cannot beat efficiently, which restricts the supply of oxygen-rich blood to the heart itself, and from circulating to the brain and the rest of the body. This increases the workload on the heart, which also increases the demand for oxygen and can result in ischemia (restriction of oxygen to the tissues) and heart attack. Ventricular fibrillation, which can be initiated by a heart attack, is rapid, irregular electrical impulses, which causes the heart muscles to quiver instead of contract. This prevents the heart from pumping and can be life-threatening, resulting in cardiac arrest.
Wolff-Parkinson-White Syndrome is a rare inherited disorder of the electrical system of the heart that is present at birth but may not become evident until later in life. An extra electrical pathway between the upper and lower chambers of the heart, shortcuts the normal electrical pathway, causing the electrical impulse to continue instead of fade, as in a regular heartbeat. This is also known as re-entry tachycardia.
Atrioventricular nodal arrhythmia
If the abnormal electrical impulse originates in the AV node itself, this is known as atrioventricular nodal tachycardia, and it is another example of re-entry tachycardia caused by an extra electrical pathway that shortcuts the heart’s electrical circuit. This type of arrhythmia is also the most common form of rapid heartbeat that begins in the upper chambers of the heart (supraventricular tachycardia).
Symptoms of arrhythmia
Symptoms of abnormal heart rhythm or dysrhythmia include palpitations, chest pain, shortness of breath, dizziness, fatigue and tiredness.
How does Aratac work?
Aratac tablets 100mg contain amiodarone, a class III antiarrhythmic that is used to treat severe tachyarrhythmia due to rhythm disorders of the heart. Amiodarone in Aratac tablets 100mg works by slowing down the electrical signals that cause tachycardia. It has a broad spectrum of activity that is effective in controlling tachyarrhythmias in atrial, nodal and ventricular tissues of the heart.
The regular heartbeat is controlled by the cardiac action potential, which is the change in voltage across the cell membrane of heart muscle cells and is how the passage of electrical impulses through the heart muscle is conducted to cause the heart to contract. The action potential is triggered by the movement of charged particles of sodium, potassium and calcium ions into and out of the heart muscle cells (cardiac myocytes) through specialised channels in the cell membrane, which open and close through the various stages of the action potential.
When positive sodium ions enter the cell, this increases the overall positive charge resulting in depolarisation. When potassium ions leave the cell, this decreases the positive charge and is known as repolarisation. Calcium ions entering the cell changes the overall charge to negative, which triggers the contraction of cardiac cells so that blood is forced out of the atria into the ventricles, followed by blood being pumped out of the ventricles (systole). In between each action potential there is a rest phase (refractory period) before the next action potential begins and the heart refills with blood (diastole).
Amiodarone in Aratac tablets 100mg works by blocking the potassium channels in the heart muscle cells that cause repolarisation of the heart during phase three of the cardiac action potential. This prolongs the duration of the action potential and increases the refractory period, which helps slow down the heartbeat and control tachyarrhythmias, particularly re-entry tachycardia, in which new action potentials are generated prematurely.
Aratac helps suppress and stabilise abnormal rhythms of the heart to restore rhythm control, which slows down the electrical signals that cause tachycardia, thereby slowing down the heartbeat. This helps relieve symptoms of arrhythmia and reduces the risk of more serious health problems.
What does Aratac contain?
Aratac tablets 100mg contain the active ingredient amiodarone, a class III antiarrhythmic used to treat severe rhythm disorders of the heart. They also contain lactose monohydrate, talc purified, cellulose microcrystalline, crospovidone, povidone, magnesium stearate, colloidal silicon dioxide.
What are the side effects of Aratac?
Most medications have some side effects, but they are not experienced by everyone. Some side effects are commonly experienced when taking Aratac, but others are not so common, and you should discuss any problems or concerns with your primary care physician.
Common side effects when taking Aratac include gastrointestinal upset (nausea, vomiting), constipation, distorted sense of taste (dysgeusia), bradycardia (slow heartbeat), thyroid disorders (hypothyroidism and hyperthyroidism), reversible corneal microdeposits, tremor, insomnia, liver problems, sleep disorders, tremor, lung disorders including pneumonitis (inflammation of the lung), pleuritis (inflammation of the pleural membranes surrounding the lungs), bronchiolitis obliterans organising pneumonia (a serious inflammatory lung condition), photosensitivity and bluish discolouration of the skin.
When should Aratac not be used?
Have a talk with your primary healthcare physician before taking Aratac 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 for Aratac you should consider the following before taking Aratac:
- Have you ever had an unusual reaction or an allergy when taking Aratac?
- Are you pregnant or breastfeeding?
- Do you have any problems with your liver?
- Do you have a thyroid disorder, as Aratac can be toxic for the thyroid gland?
- Do you have hypotension (low blood pressure), or heart failure?
- Do you have problems with your lungs or severe respiratory failure?
- Do you have any eye disorder as Aratac can cause eye problems?
- Are you due to have a general anaesthetic?
What medications interact with Aratac?
Some medicines interact with Aratac and may affect the way it works or are affected by Aratac or increase side effects; you should discuss possible interactions with your primary care physician. These may include other antiarrhythmics, anti-psychotics like pimozide and haloperidol, anti-depressants like amitriptyline, lithium for mood disorders, antihistamines like terfenadine and astemizole, anti-malarials like quinine, quinolone antibiotics like moxifloxacin, beta-blockers like propranolol, calcium channel blockers like diltiazem, verapamil, satins like simvastatin, atorvastatin for high cholesterol, stimulant laxatives like bisacodyl, some diuretics, systemic corticosteroids, the antifungal amphotericin B given intravenously, digoxin for heart conditions, anticoagulants like warfarin and dabigatran, antivirals like sofosbuvir for HIV.
If other medications may interact with Aratac, your doctor will discuss these with you.
How should Aratac be taken and for how long?
You should take your Aratac tablets 100mg swallowed whole with a glass of water, with or without food, three times daily for one week, then twice daily for another week. The dose you take and how often may be adjusted depending on your doctor’s recommendation and if you experience side effects. You should continue to take your Aratac tablets 100mg for as long as recommended by your doctor
Missed dose of Aratac
If you miss a dose of Aratac tablets 100mg 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 Aratac be stored?
You should store your Aratac tablets 100mg below 25°C in a cool dry place.