Flecainide acetate

Pharmacological properties

flecainide acetate is an antiarrhythmic agent of IC class, intended for the treatment of life-threatening symptomatic ventricular arrhythmias and supraventricular arrhythmias of a high degree of severity.

According to the electrophysiological properties, flecainide is a local anesthetic (class IC) of antiarrhythmic action. This is a local amide type anesthetic, structurally similar to procainamide and encainide, since these substances are also benzamide derivatives.

Flecainide as a compound of class ІС has three main properties: pronounced inhibition of the fast sodium channels of the heart; a slow onset of action and a shift in the kinetic characteristics of the inhibition of sodium channels (which is the result of slow binding and dissociation from sodium channels); the differentiated effect of the drug on the duration of the change in the bioelectric potential of the muscles of the ventricles and Purkinje fibers, namely: the absence of influence on the former and a significant reduction in the duration of the shift for the latter. This combination of properties provides a significant decrease in the conductivity of the fibers, the depolarization of which depends on the fast sodium channels, with a moderate increase in the effective refractory period, as evidenced by the results of studies using isolated cardiac tissues. The indicated electrophysiological properties of acetate flecainide are due to the possibility of lengthening the P – R interval and the QRS complex on an ECG. In a very high concentration, flecainide causes a weak suppression of the slow myocardial channels. This effect is associated with a negative inotropic effect.

Pharmacokinetics Oral flecainide Sandoz is absorbed almost completely and does not undergo an active metabolic transformation of the first passage. According to available information, the bioavailability of flecainide in the form of acetate is approximately 90%. The range of therapeutic plasma concentrations, as is commonly believed, is 200-1000 ng / ml. With a / in the introduction of the average duration of the period until reaching C_max in blood plasma is 0.67 hours, and the average bioavailability indicator is 98% compared with 1 hour and 78%, respectively, when taking the drug in the form of a solution for oral administration and 4 hours and 81%, respectively, in the form of tablets. About 40% of flecainide binds to plasma proteins.

Flecainide Sandoz crosses the placenta and is excreted in breast milk.

Flecainide Sandoz undergoes an active metabolic transformation (depending on genetic polymorphism), the two main metabolites are meta-O-dealkylated flecainide and meta-O-dealkylated flecainide lactam, both metabolites are relatively active. Metabolic conversion occurs with the participation of the enzyme of the cytochrome P450 system, namely the CYP 2D6 enzyme, and is associated with genetic polymorphism.

Flecainide Sandoz is excreted mainly in the urine, about 30% of the dose received is excreted in the form of an unchanged substance, the rest in the form of metabolites. About 5% is excreted in feces. The level of excretion of flecainide decreases with renal failure, liver disease, heart failure and alkaline urine. With hemodialysis, only 1% of flecainide is excreted in the form of an unchanged substance. T_½ flecainide is about 20 hours.

Indications

Av-nodal resistant tachycardia; arrhythmias associated with Wolf-Parkinson-White syndrome and similar disorders caused by the presence of additional pathways - in case of inefficiency of other types of treatment.

Symptomatic paroxysmal ventricular arrhythmia of a high degree of severity, threatening the life of the patient, in the absence of a response to other types of therapy. It is also used for intolerance or inability to conduct other forms of therapy.

Paroxysmal atrial arrhythmia (atrial fibrillation, atrial flutter, atrial tachycardia) in patients with adverse symptoms after conversion, provided there is an undoubted need for therapy, which is confirmed by the severity of the clinical symptoms if other treatments are ineffective.

Before starting use, it is necessary to exclude the presence of heart diseases of organic origin and / or violation of the ejection fraction of the left ventricle, since in this case the risk of an undesirable increase in arrhythmia increases.

Application

The drug is administered orally. to eliminate the effect of food on drug absorption, flecainide sandoz should be taken on an empty stomach or 1 hour before meals. a tablet of flecainide sandoz 100 mg can be divided into two equal parts.

The beginning of therapy with the use of flecainide acetate and changes in the dosage regimen should be carried out under the supervision of ECG monitoring and control of the concentration of the substance in the blood plasma. Some patients require hospitalization for this period of time, in particular patients with life-threatening ventricular arrhythmia. The decision on the need for hospitalization is made by a specialist. In patients with heart diseases of organic origin, especially if there is a history of myocardial infarction, flecainide therapy should be started only if other antiarrhythmic drugs, with the exception of IC class drugs (especially amiodarone), are ineffective or not tolerated by the patient, and provided that non-drug treatment (surgery, amputation, implantation of a defibrillator) is not indicated. During the period of therapy, constant ECG monitoring and control of the concentration of the substance in the blood plasma are necessary.

Adults and children over 13 years old. Supraventricular arrhythmia: the recommended initial dose is 50 mg 2 times a day. For most patients, taking the indicated dose provides control of undesirable symptoms. If necessary, the dose can be increased to a maximum of 300 mg / day.

Ventricular arrhythmia: the recommended initial dose is 100 mg 2 times a day. The maximum daily dose is 400 mg, but this dose is used only in the treatment of patients with large physique or, if necessary, to quickly ensure control of arrhythmia. After 3-5 days, a gradual dose adjustment is recommended to a minimum sufficient level that provides control of arrhythmia. With prolonged use of the drug, a dose reduction is possible.

Use in the treatment of elderly patients. In the treatment of elderly patients, the drug is used in an initial daily dose not exceeding 100 mg (1 tablet 50 mg 2 times a day), since the rate of removal of flecainide from blood plasma in people of this age category can be reduced. This should also be considered when adjusting the dose. The maximum dose for elderly patients should not exceed 300 mg (150 mg 2 times a day).

Plasma level. According to indicators of elimination of ventricular extrasystoles, to ensure the maximum therapeutic effect, the content of the substance in the blood plasma should be 200-1000 ng / ml. Plasma concentrations greater than 700–1000 ng / ml are associated with an increased likelihood of adverse events.

Impaired renal function. In the treatment of patients with severe renal impairment (creatinine clearance 35 ml / min / 1.73 m² or lower) the initial dose should not exceed 100 mg / day (or 50 mg 2 times a day). When using the drug in the treatment of such patients, monitoring of the concentration of the substance in the blood plasma is strongly recommended. Depending on the effect and tolerance, the dose can be gradually and carefully increased. After 6-7 days, the dosage regimen is subject to correction taking into account the effectiveness and tolerability of therapy.In some patients with severe renal impairment, the clearance of flecainide is very low, resulting in an increase in the duration of T_½ (60–70 hours).

Impaired liver function. When using the drug in the treatment of patients with impaired liver function, careful monitoring is necessary, the initial dose should not exceed 100 mg / day (50 mg 2 times a day).

In the treatment of patients with an implanted pacemaker, the drug should be used with caution, the daily dose should not exceed 100 mg, the dose is divided into 2 doses.

With simultaneous use with cimetidine or amiodarone, careful monitoring is necessary. In the treatment of some patients, the dose should be reduced, the daily dose should not exceed 100 mg, which is divided into 2 doses. It is necessary to monitor the condition of patients during both initial and maintenance therapy.

It is recommended to monitor the concentration of a substance in blood plasma and ECG monitoring (monitoring ECG once a month). At the stage of initial therapy and with increasing doses, an ECG examination should be carried out every 2–4 days.

When using the drug Flecainide Sandoz in the treatment of patients in need of reduced doses, ECG monitoring should often be performed (in addition to monitoring the concentration of flecainide in the blood plasma). Dose adjustment is carried out at intervals of 6-8 days. To control the individual dosing regimen, an ECG examination of such patients should be carried out 2 and 3 weeks after the start of therapy.

Contraindications

Hypersensitivity reaction to flecainide or any of the excipients of the drug.

Heart failure, a history of myocardial infarction, with asymptomatic ventricular ectopia or asymptomatic unstable ventricular tachycardia.

Cardiogenic shock.

Long-term atrial fibrillation, in the treatment of which no attempt was made to convert sinus rhythm, as well as valvular heart disease with significant impaired hemodynamic parameters.

Decreased or impaired ventricular function in the presence of cardiogenic shock, high severity bradycardia (50 beats per minute), high severity of arterial hypotension.

Use in combination with class I antiarrhythmic drugs (sodium channel blockers).

Brugada syndrome.

In the absence of the possibility of cardiac pacing, flecainide should not be used in the treatment of patients with impaired sinus function, atrial conduction disturbance, with AV block II or higher, with blockade of the bundle of the bundle or block of the distal sections.

Asymptomatic ventricular arrhythmia or mild symptoms of ventricular arrhythmia.

Side effects

Like other antiarrhythmic drugs, flecainide can cause increased arrhythmias. perhaps an increase in the intensity of symptoms of an existing arrhythmia or the development of a new episode. the risk of proarrhythmic effects is most pronounced in patients with heart diseases of organic origin and / or with significant impaired left ventricular function.

The most common side effects are AV-block II – III severity, bradycardia, heart failure, chest pain, myocardial infarction, hypotension, cessation of sinus node activity, tachycardia (atrial and ventricular tachycardia) and severe heartbeat.

Frequent adverse events such as dizziness and visual impairment occur in approximately 15% of patients. These adverse events, as a rule, are temporary and disappear with further treatment or a dose reduction. The above list of side effects is based on the experience gained during the clinical trials and the information obtained in the framework of pharmacological supervision after registration of the drug.

Side effects are classified by organ systems and classes, as well as frequency. The frequency is determined as follows: very often (≥1 / 10), often (≥1 / 100, 1/10), infrequently (≥1 / 1000, 1/100), single (≥1 / 10,000, 1/1000) , rarely (1/10 000), the frequency is unknown (cannot be determined from the available data).

From the hemopoietic system and the lymphatic system: infrequently - a decrease in the number of red blood cells, a decrease in the number of white blood cells and a decrease in the number of platelets.

On the part of the immune system: rarely - an increase in the number of antinuclear antibodies, associated or not associated with systemic inflammation.

From the psyche: isolated - hallucinations, depression, confused state of consciousness, anxiety, amnesia, insomnia.

From the side of the nervous system: very often - dizziness, which usually passes quickly; single ones - paresthesia, ataxia, hypesthesia, hyperhidrosis, fainting, tremors, flushing, drowsiness, headache, peripheral neuropathy, convulsions, dyskinesia.

From the side of the organ of vision: very often - visual impairment, such as diplopia and blurred vision; rarely - precipitate on the cornea.

From the side of the organ of hearing and balance: single - ringing in the ears, dizziness like vertigo.

From the side of the cardiovascular system: often - pro-arrhythmic effect (most likely for patients with heart diseases of organic origin); infrequently - patients with atrial flutter may develop (1: 1) AV conduction with an increase in heart rate; the frequency is unknown - possibly a dose-dependent increase in the P – R interval and the QRS complex.

Changing the threshold of sensitivity to a pacemaker signal.

Grade II – III AV block, cardiac arrest, bradycardia, heart failure / congestive heart failure, chest pain, hypotension, myocardial infarction, severe heartbeat, cessation of sinus node activity, tachycardia (atrial and ventricular) or atrial fibrillation. The manifestation of symptoms of the existing Brugada syndrome.

From the respiratory system: often - shortness of breath; single - pneumonitis; frequency unknown - pulmonary fibrosis, interstitial lung disease.

From the digestive system: infrequently - nausea, vomiting, constipation, abdominal pain, decreased appetite, diarrhea, dyspepsia, flatulence.

From the hepatobiliary system: single - increased activity of liver enzymes, with or without jaundice; frequency unknown - impaired hepatic function.

From the skin and subcutaneous tissues: infrequently - allergic dermatitis, including rash, alopecia; single - urticaria of a severe degree; rarely - photosensitivity reaction.

Systemic disorders and disorders associated with the injection site: often - asthenia, fatigue, fever, edema.

special instructions

Flecainide sandoz for oral administration should be prescribed only in a hospital setting or under the direct supervision of a specialist for the treatment of patients with:

AV-nodal resistant tachycardia, arrhythmias associated with Wolf-Parkinson-White syndrome and similar disorders associated with the presence of additional pathways.

Paroxysmal atrial fibrillation, in the presence of adverse symptoms.

The use of the drug for other indications should begin in a hospital setting.

Flecainide has been shown to increase the risk of death for patients after myocardial infarction with asymptomatic ventricular arrhythmia.

Flecainide Sandoz, like other antiarrhythmic drugs, can cause increased arrhythmia, that is, it can cause more severe arrhythmia, an increase in the frequency of arrhythmia episodes, or an increase in the intensity of undesirable symptoms.

Avoid the use of flecainide in the treatment of patients with heart disease of organic origin or impaired left ventricular ejection fraction.

Flecainide should be used with caution in the treatment of patients with acute development of atrial fibrillation after cardiac surgery.

Flecainide causes a prolongation of the Q – T interval and an increase in the QRS complex by 12–20%. The effect on the Q – T interval is negligible.

Brugada symptom may appear when a patient receives flecainide. If changes are detected by the results of an ECG examination, which may indicate the presence of Brugada syndrome, during therapy with flecainide, the appropriateness of canceling further therapy should be considered.

Since the removal of flecainide from the blood plasma of patients with severe liver dysfunction can be much slower, flecainide should not be used in the treatment of such patients, unless the potential benefit outweighs the potential risks. They recommend monitoring the concentration of a substance in blood plasma.

Flecainide Sandoz should be used with caution in the treatment of patients with impaired renal function (creatinine clearance 35 ml / min / 1.73 m² or lower); therapeutic monitoring recommended.

The rate of elimination of flecainide from the blood plasma of elderly patients can be reduced. This should be remembered when adjusting the dosage regimen.

Imbalance in electrolytes (e.g. hypokalemia and hyperkalemia) should be corrected before starting treatment with flecainide.

Severe bradycardia or significant arterial hypotension should be eliminated before starting treatment with flecainide.

It is known that Flecainide Sandoz increases the threshold of sensitivity of the endocardium to pacemaker signals, that is, the sensitivity of the endocardium to pacemaker decreases. This effect is reversible and affects the threshold of acute rather than chronic sensitivity. So, flecainide should be used with caution in the treatment of patients with established permanent or temporary pacemakers and should not be used in the treatment of patients with a high threshold for pacemaker sensitivity and in the case of using a non-programmable pacemaker in the absence of proper resuscitation equipment.

As a rule, doubling the frequency or amplitude of the stimulating impulse (voltage) is sufficient to normalize the work of the heart, but at the initial stages after implantation, when a patient receives flecainide, it is very difficult to provide a ventricular sensitivity threshold of 1 V.

There were difficulties with defibrillation. In most of these cases, patients had a history of heart disease with an increase in heart size, myocardial infarction, arteriosclerotic heart disease, and heart failure.

There are reports of cases of increased rate of ventricular contraction with atrial fibrillation in the absence of a therapeutic effect. Flecainide Sandoz has a selective effect, increases the refractory period of anterograde and especially retrograde conduction from the sinus node to the ventricles of the heart. This effect is manifested on the ECG of most patients as an extension of the corrected Q – T interval, so the effect on the Q – T interval is negligible. However, there are reports of cases of prolongation of the Q – T interval by 4%. However, this effect is less pronounced than with class Ia antiarrhythmic drugs.

Use in pediatric practice. Flecainide Sandoz is not recommended for use in the treatment of children under the age of 12 years due to a lack of adequate safety and efficacy data.

Dairy products (milk, baby food, and possibly yoghurts) can reduce the absorption of flecainide in children and newborns.The toxicity of flecainide, which was used in children subject to a reduction in milk intake, as well as in newborns who have replaced dairy baby food with a diet containing glucose, has been reported.

Use during pregnancy. Flecainide Sandoz crosses the placenta when taking the drug during pregnancy. Therefore, it should not be used during pregnancy if the expected benefit does not exceed the potential risk.

Use during lactation. Flecainide Sandoz passes into breast milk. The concentration in the blood plasma of a breast-fed baby is 5-10 times lower than the therapeutic. If treatment is necessary, breast-feeding should be discontinued.

Children. Flecainide Sandoz is not recommended for use in the treatment of children under the age of 13 years due to the lack of adequate data on safety and effectiveness.

The ability to influence the reaction rate when driving vehicles or working with other mechanisms. It is recommended to refrain from driving vehicles or working with other mechanisms, given the possibility of developing dizziness, visual impairment.

Interactions

Class I antiarrhythmic drugs. flecainide sandoz should not be used concurrently with class i antiarrhythmic drugs.

Class II antiarrhythmic drugs. The possibility of enhancing the undesirable inotropic effect of class II antiarrhythmic drugs, such as β-adrenergic receptor blockers, while using it with flecainide, should be considered.

Class III antiarrhythmic drugs. With the simultaneous use of flecainide with amiodarone, the usual dose of flecainide should be halved and careful monitoring of the patients condition should be ensured for the timely detection of adverse events. It is also recommended that the concentration of the substance in blood plasma be monitored.

Class IV antiarrhythmic drugs. The simultaneous use of flecainide with calcium channel blockers, such as verapamil, should be carried out with caution.

There are possible side effects that threaten the patients life, associated with drug interactions that cause an increase in the concentration of the substance in the blood plasma. The metabolic conversion of flecainide is provided mainly by CYP 2D6 isoenzymes, and when used with drugs that inhibit (e.g. antidepressants, antipsychotics, propranolol, ritonavir, some antihistamines) or increase the activity (e.g. phenytoin, phenobarbital, carbamazepine) of this enzyme, there is a corresponding increase or a decrease in the concentration of flecainide in blood plasma.

An increase in the concentration of flecainide in blood plasma may also be due to impaired renal function due to a decrease in the clearance of flecainide.

Hypokalemia, as well as hyperkalemia, or other disturbances in electrolyte balance should be adjusted before flecainide is used. Hypokalemia may result from the simultaneous use of diuretics, corticosteroids, or laxatives.

Antihistamines. The risk of ventricular arrhythmias increases when prescribed together with misolastine and terfenadine. Concurrent use should be avoided.

Antiviral agents. The concentration of the substance in blood plasma increases with simultaneous use with ritonavir, lopinavir and indinavir (increased risk of ventricular arrhythmias) (simultaneous use should be avoided).

Antidepressants. Fluoxetine, paroxetine and other antidepressants cause an increase in the concentration of flecainide in blood plasma; while taking tricyclic antidepressants, the risk of ventricular arrhythmias increases.

Antiepileptic drugs.Limited data from patients taking the drug along with enzyme activators (phenytoin, phenobarbital, carbamazepine) indicate a 30% increase in the rate of flecainide excretion.

Antipsychotics. Clozapine - increased risk of arrhythmias.

Antimalarial drugs. Quinine helps to increase the concentration of flecainide in blood plasma.

Antifungal agents. Terbinafine can cause an increase in the concentration of flecainide in blood plasma due to inhibition of the activity of the CYP 2D6 enzyme.

Diuretics The class effect of drugs, hypokalemia, the consequence of which is an increase in cardiotoxic effects.

N₂antihistamines (for the treatment of stomach ulcers). Antagonist N₂receptors, cimetidine, inhibits the metabolic conversion of flecainide. In healthy volunteers who received cimetidine (1 g / day) for 1 week, the AUC value of flecainide increased by about 30%, and T_½ increased by about 10%.

Drugs to help quit smoking: simultaneous administration of bupropion (the metabolic conversion of which is carried out with the participation of the enzyme CYP 2D6) and flecainide should be carried out with caution and begin treatment with the minimum dose of the recommended range. If bupropion is prescribed when the patient receives flecainide, consider the advisability of lowering the dose of the latter.

Cardioglycosides. With the use of flecainide, an increase in the content of digoxin in blood plasma by 15% is possible, which is unlikely to have clinical value when the concentration in the blood plasma of patients in the therapeutic range. It is recommended that the level of digoxin in the blood plasma of patients receiving digitalis preparations be determined at least 6 hours after the use of digoxin, regardless of the dose, before or after taking flecainide.

Anticoagulants. Flecainide can be used simultaneously with anticoagulants for oral use.

Overdose

An overdose of flecainide sandoz is life threatening and requires immediate medical attention. hypersensitivity to the drug and an increase in plasma concentration to a level exceeding the therapeutic may also be due to interaction with other drugs. specific antidote unknown. There is no known method to quickly remove flecainide sandoz from the body. dialysis or hemoperfusion is ineffective.

Supportive therapy is needed, it is possible to remove the substance not yet absorbed from the digestive tract. In the future, it is possible to use drugs of inotropic action or stimulators of cardiac activity, such as dopamine, dobutamine or isoproterenol, as well as mechanical ventilation and measures to maintain blood circulation (for example, an auxiliary circulation pump). The feasibility of using a temporary transvenous pacemaker should be considered in case of conduction blockade. Since T_½ blood plasma is about 20 hours, these measures of maintenance therapy should be carried out for a long time.

Forced diuresis with oxidation of urine theoretically promotes excretion of the substance.

Storage conditions

In the original packaging at a temperature not exceeding 25 ° C.

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