Living in the modern world has made many things that were difficult to find or buy in the past much more accessible now. However, it is quite terrifying to think that medicine that should only be received or used when prescribed by a doctor, can be easily available in the marketplace. It is important to only buy medication that is marketed as over-the-counter drugs and to only use medication prescribed by a doctor when the medication should only be available with prescription. In this article, we will learn more about dronedarone.
Dronedarone is a drug that belongs to a class of medications known as antiarrhythmics. Antiarrhythmic medications are medications that prevent and treat abnormal heartbeats. This abnormal heartbeat is caused by disruption in the way the heart’s electrical system works. Antiarrhythmic medication in general are categorised according to the Vaughan-Williams (VW) classification system. This system classifies medications to its primary ways of working in the human body (mechanism of action) but there may be several medications that have properties from multiple classes.
Dronedarone is a Class III antiarrhythmic drug. Class III antiarrhythmic drug works by inhibiting delayed rectifier potassium currents. The prolongation of repolarization is a typical feature of this group. This increases the refractory period (resting state in a depolarized cardiac cell) and widens the QT interval.
Just as with other class III antiarrhythmic drugs, dronedarone blocks potassium channel in phase 3 of action potential and slows the efflux of potassium cation back out of the myocyte (heart cell). This slows the repolarization rate of the cell and widening the action potential’s plateau phase. Lengthening of the QT interval on the ECG represents the refractory period of atrial, ventricular and Purkinje cells that are increased. Dronedarone also blocks the sodium ion channels and exerts antiadrenergic effects.
Dronedarone is a derivative of amiodarone that is not iodinated by benzofuran. Is dronedarone the same as amiodarone? No, it is not. Yes, it is true that dronedarone appears to share the same pharmacological actions with amiodarone, but it lacks the iodine components that play a role for the multiple organ toxicities of the latter. Thus, dronedarone is shown in studies to be safer than amiodarone. Furthermore, dronedarone is better tolerated than amiodarone.
Dronedarone is mostly used to treat those who have had atrial fibrillation in the past and currently with normal heart rhythm. Atrial fibrillation occurs when the abnormal electrical impulses suddenly start firing in the atria (upper chamber of the heart). This causes an irregular and abnormal high heart rate. Dronedarone is used to reduce risk of hospitalisation for heart problems with paroxysmal or persistent atrial fibrillation. It is recommended to be used for clinically stable patients associated with risk for recurrent atrial fibrillation as the first choice for rhythm control in patients with no coronary artery disease, hypertension without left ventricular hypertrophy and heart disease. Dronedarone is proven to be effective in reducing the likelihood for repeated atrial fibrillation in patients who have been cardioverted back to sinus rhythm.
The recommended dose for oral dronedarone is 400 mg, two times daily. Due to the fact that many patients who require dronedarone therapy are already on other antiarrhythmic agents, it is common for patients to have medications to be switched to prevent adverse effects. For example, dronedarone can be started on a patient after about 48 hours of discontinuation of amiodarone. Dronedarone comes in tablet form. Patients need to take dronedarone as instructed by the doctor which is typically one tablet in the morning and one in the evening. It is best to take dronedarone at the same time everyday to help patients remember taking it regularly. Patients should not take more or less dronedarone than what is prescribed by the doctor.
Similar to many other medications, dronedarone does come with possible side effects. Common side effects include nausea, vomiting, abdominal pain, skin rash, diarrhoea and slow heart beats. Rare side effects but serious ones such as liver injury, stroke and heart failure should receive emergency care as this can be life-threatening. Dronedarone may cause unwanted side effects not mentioned previously. Patients are encouraged to talk with their doctor if they experience any side effects or unusual problems when taking dronedarone.
Patients who have other medical conditions should tell their doctor about their condition. Patients who already take other medications or supplements should notify this to the doctor before taking dronedarone. This is because specific medications such as simvastatin, digoxin, verapamil, diltiazem, diuretics and tacrolimus, have shown to cause reaction with dronedarone when taken together. Thus, letting doctors acknowledge all medications or supplements help to ensure patients that take dronedarone have less chances for adverse drug events or side effects.
In essence, dronedarone is effective in reducing the likelihood for recurrent atrial fibrillation. It may be less effective when compared to amiodarone but is well tolerated and much safer than amiodarone. Dronedarone is recommended as an antiarrhythmic agent of choice to clinically stable patients with associated risk factors for recurrent atrial fibrillation that have no coronary heart disease, hypertension without left ventricular hypertrophy or heart disease.