The active substance flecainide is classified as an antiarrhythmic agent. It is used for the therapy of cardiac arrhythmias.
What is flecainide?
Flecainide is an antiarrhythmic drug used to treat cardiac arrhythmias. The drug was discovered in the 1970s. It was approved for use in Europe in 1982 and was marketed in Germany under the trade names Flecagamma and Tambocor. In 2004, flecainide‘s patent protection expired. Thereafter, various generics containing the drug were offered in Germany. Flecainide has the disadvantage that it can itself cause cardiac arrhythmias. This occurs primarily through interactions with other drugs or too high a dosage.
Pharmacologic effects on the body and organs
Flecainide belongs to the class Ic antiarrhythmic drug group. As a result, the drug acts in the same way as the other antiarrhythmics in this group. The human heart is composed of a chamber (ventricle) on both sides and an atrium (atrium). From there, the blood is pumped out via a valve mechanism. The heart rhythm is generated within the sinus node of the right atrium. Special pacemaker cells are located there, whose function is to clock the heart pumping rate. First, they cause the two atria to contract. This is followed by the two ventricles. A cardiac arrhythmia occurs either in the ventricle or in the atrium. Likewise, it can affect both structures at the same time. If the heart beats too intensively, which physicians call tachycardia, its contraction is so rapid that it is no longer able to pump blood effectively. This is where flecainide comes into play. The active ingredient achieves a reduction in the conduction velocity of the sinus node‘s conduction pathways. The impulse for the tachycardia originates either from the ventricle or from the atrium. Flecainide belongs to the group of sodium channel blockers. This means that the active ingredient stops the supply of sodium ions. As a result, no further action potentials can form, which leads to dampening of the heart muscle activity. In this way, a slowing of the heart rate can be achieved. Flecainide acts rapidly, so there is no need for conversion of the active ingredient within the body. Since the organism can access the full dose of the drug, the patient’s condition quickly improves. Therefore, flecainide is also suitable for the treatment of life-threatening cardiac arrhythmias. Following its intake, flecainide is rapidly absorbed by the blood through the intestines. The highest concentration occurs after about three hours. The active substance is broken down in the liver. It is excreted in the urine via the kidneys. After about 20 hours, only about 50 percent of the drug remains in the body.
Medical use and use for treatment and prevention.
Flecainide is used to treat specific forms of cardiac arrhythmias. These are supraventricular tachyarrhythmias, which can be life-threatening. Also among the drug’s uses is an irregular and rapid heartbeat due to tachycardic supraventricular arrhythmias such as palpitations. This originates from the AV node of the heart and is known in medicine as AV junctional tachycardia. Other indications include paroxysmal atrial fibrillation and supraventricular tachycardia in WPW syndrome. In addition to the treatment of cardiac arrhythmias, flecainide is also suitable for their prevention. The drug is taken in the form of tablets. The patient takes them with water during or after a meal. The usual dosage is two times 50 to 100 grams of flecainide per day. If the patient has a higher body weight or in a special case, up to 400 milligrams per day can be administered. As a rule, treatment starts gradually with a low dose, which is then gradually increased. By following this procedure, patients tolerate the drug better and suffer side effects less frequently.
Risks and side effects
Taking flecainide may be associated with adverse side effects. These primarily include visual disturbances, dizziness, and disturbances of balance.In addition, approximately 10 out of 100 patients experience headaches, sleep problems, anxiety, depression, sensory disturbances such as tingling, tremors, fatigue, rashes and redness on the skin, feelings of weakness, tinnitus, nausea, vomiting, difficulty breathing, water retention, constipation, and cardiac arrhythmias. Other side effects may include abdominal pain, gastrointestinal problems, unsteadiness when walking, movement disorders, increased sweating, drowsiness, diarrhea, a refusal to eat, and fever. In rare cases, people also suffer from hives, hair loss, nerve disorders in the limbs, memory problems, convulsions, pneumonia, and confusion or delusions. Most side effects occur at the beginning of treatment and improve as treatment progresses. In some cases, reducing the dose may help. If the patient is hypersensitive to flecainide, has limited cardiac output, or has a blockage of conduction within the atrium, the antiarrhythmic must not be taken. Life-threatening ventricular arrhythmias are an exception. The use of other drugs that affect the heart can also be problematic. These are primarily cardiac glycosides such as digitoxin or digoxin, beta blockers such as bisoprolol or metoprolol, and calcium blockers such as verapamil. If concomitant use must occur, it may be appropriate to reduce the flecainide dose. In addition, ECG checks should be performed regularly. Pregnant and breastfeeding women should not take flecainide. The same applies to children younger than 12 years of age.
