Indications
Propafenone is used to prevent and treat certain abnormal heart rhythms (arrhythmias), such as paroxysmal atrial fibrillation (episodes of a fast, irregular heartbeat starting in the upper chambers of the heart) and some serious ventricular arrhythmias, in people whose heart structure is otherwise mostly normal. It is started and monitored by a doctor, often a heart specialist.
How It Works
Propafenone slows the movement of sodium into heart muscle cells. This steadies the electrical signals in the heart and helps keep a normal rhythm. It also has a mild beta-blocking effect, which can slow the heart rate.
Dosage and Administration
Take exactly as prescribed. For adults, treatment is usually started at 150 mg every 8 hours, and the doctor may increase it gradually (for example to 300 mg every 8 to 12 hours) depending on response, ECG results and side effects. Swallow tablets whole with water after food. Do not stop suddenly or change the dose without advice.
Interactions
Many medicines interact. Propafenone can raise levels of Digoxin, Warfarin, beta blockers such as Metoprolol, and Ciclosporin. Medicines such as Ketoconazole, Erythromycin, Clarithromycin, Ritonavir, Fluoxetine, Paroxetine, Quinidine and Cimetidine can raise propafenone levels. Rifampicin can lower them. Other heart rhythm medicines and medicines that prolong the QT interval add to the risk. Avoid grapefruit juice. Tell your doctor about every medicine you take.
Contraindications
Do not use in heart failure that is not controlled, shock caused by heart problems, a recent heart attack (in many cases), very slow heartbeat, certain heart block or conduction problems without a pacemaker, Brugada syndrome, very low blood pressure, severe asthma or COPD, serious salt imbalance, myasthenia gravis, or allergy to Propafenone.
Side Effects
Common side effects include dizziness, a metallic or bitter taste, nausea, vomiting, constipation, tiredness, headache, blurred vision and dry mouth.
Get urgent medical help if you have fainting, chest pain, a new or worse irregular, very slow or very fast heartbeat, worsening breathlessness or swelling of the ankles, fever or sore throat that does not go away (a possible sign of low white blood cells), or signs of an allergic reaction.
Pregnancy and Lactation
Use in pregnancy only if the doctor decides the benefit is greater than the risk. It passes into breast milk; ask your doctor before breastfeeding.
Precautions and Warnings
Regular ECGs and check-ups are needed. Like other medicines of this type, it can sometimes cause new or worse arrhythmias. Use with care in liver or kidney disease, the elderly, and people with pacemakers (settings may need checking). Potassium and magnesium imbalances should be corrected first. It may cause dizziness: take care when driving.
Overdose
Overdose is dangerous and can cause very low blood pressure, slow or irregular heartbeat, seizures and collapse. Go to the nearest hospital straight away.
Therapeutic Class
Class IC antiarrhythmic.
Storage
Store below 30°C in a dry place, away from light and out of the reach of children.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.