Indications
Amiodarone Hydrochloride is an antiarrhythmic medicine, meaning it is used to control abnormal heart rhythms. It is used for serious or life-threatening rhythm problems such as ventricular tachycardia and ventricular fibrillation, and for atrial fibrillation or atrial flutter when other medicines are not suitable or have not worked. It is usually started in hospital or by a heart specialist.
How It Works
The heart beats in a regular pattern controlled by electrical signals. Amiodarone slows down these signals and lengthens the time the heart muscle needs to recover between beats. This helps stop fast, irregular rhythms and keeps the heartbeat steady. It builds up slowly in the body, so its full effect can take days to weeks, and it stays in the body for months after stopping.
Dosage and Administration
The dose is set by a doctor and must be taken exactly as prescribed. Treatment usually starts with a higher loading dose for one to several weeks, then the dose is lowered to the smallest amount that keeps the rhythm controlled. Tablets can be taken with or without food, but take them the same way each day. The injection is given into a vein by a doctor or nurse in hospital with heart monitoring. Do not stop taking it on your own.
Interactions
Amiodarone interacts with many medicines. It can raise the levels and effects of Warfarin, Digoxin, Simvastatin and other statins, Ciclosporin and some medicines for HIV. Combining it with Sofosbuvir (a hepatitis C medicine), beta blockers or some calcium channel blockers can slow the heart dangerously. Other medicines that affect heart rhythm, such as some antibiotics, antipsychotics and antidepressants, raise the risk of serious rhythm problems. Avoid grapefruit juice. Always tell your doctor and pharmacist about every medicine, herbal product and supplement you use.
Contraindications
Do not use amiodarone if you have a very slow heartbeat or certain heart block conditions without a pacemaker, an overactive or underactive thyroid that is not controlled, an allergy to amiodarone or iodine, or if you are breastfeeding. The injection is not used in severe low blood pressure or severe breathing failure.
Side Effects
Common side effects include nausea, constipation, tiredness, tremor, sensitivity of the skin to sunlight, a blue-grey skin colour after long use, small deposits in the eye that can cause halos around lights, and changes in thyroid function. Less common but serious effects include lung inflammation, liver damage, nerve problems in the hands and feet, and new or worse heart rhythm problems.
Get urgent medical help if you have new or worsening shortness of breath or cough, chest pain, fainting, a very slow or very fast heartbeat, yellow skin or eyes, blurred or reduced vision, or signs of a serious allergic reaction such as swelling of the face or difficulty breathing.
Pregnancy and Lactation
Amiodarone can affect the baby’s thyroid and heart, so it is used in pregnancy only when the benefit clearly outweighs the risk. It passes into breast milk, and breastfeeding is not recommended during treatment. Talk to your doctor if you are pregnant, planning a pregnancy or breastfeeding.
Precautions and Warnings
Your doctor will check your thyroid, liver, lungs, eyes and heart (ECG) before and during treatment. Protect your skin from the sun with clothing and sunscreen. Tell any surgeon or anaesthetist that you take amiodarone. Use extra care in older people and in those with heart failure or liver or lung disease. Because the medicine stays in the body for a long time, side effects and interactions can continue for months after stopping.
Overdose
Too much amiodarone can cause a very slow heartbeat, low blood pressure, heart block and dangerous rhythm changes. If an overdose is suspected, go to hospital immediately. Treatment is supportive, with heart monitoring.
Therapeutic Class
Antiarrhythmic agent (class III).
Storage
Store tablets below 30°C in a dry place, away from light and out of the reach of children. Injections are stored as directed on the pack.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.