Flecainide Side Effects

Brand Names: Tambocor

Please note - some side effects for Flecainide may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA at http://www.fda.gov/medwatch/ or 1-800-FDA-1088 (1-800-332-1088).

Side Effects of Flecainide - for the Consumer

Flecainide

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Flecainide:

Blurred vision; constipation; difficulty focusing; dizziness; faintness; headache; nausea; seeing spots; stomach discomfort; tiredness; unsteadiness; weakness.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); chest pain; difficulty breathing; fainting; fast heartbeat; heart attack; life-threatening irregular heartbeat; lightheadedness; pounding in the chest; seizures; tremor; yellowing of the skin or eyes.

Flecainide Side Effects - for the Professional

Flecainide

In post-myocardial infarction patients with asymptomatic PVCs and non-sustained ventricular tachycardia, Flecainide therapy was found to be associated with a 5.1% rate of death and non-fatal cardiac arrest, compared with a 2.3% rate in a matched placebo group.

Adverse effects reported for Flecainide, described in detail in the WARNINGS section, were new or worsened arrhythmias which occurred in 1% of 108 patients with PSVT and in 7% of 117 patients with PAF; and new or exacerbated ventricular arrhythmias which occurred in 7% of 1330 patients with PVCs, non-sustained or sustained VT. In patients treated with Flecainide for sustained VT, 80% (51/64) of proarrhythmic events occurred within 14 days of the onset of therapy. 198 patients with sustained VT experienced a 13% incidence of new or exacerbated ventricular arrhythmias when dosage was initiated at 200 mg/day with slow upward titration, and did not exceed 300 mg/day in most patients. In some patients, Flecainide treatment has been associated with episodes of unresuscitatable VT or ventricular fibrillation (cardiac arrest). New or worsened CHF occurred in 6.3% of 1046 patients with PVCs, non-sustained or sustained VT. Of 297 patients with sustained VT, 9.1% experienced new or worsened CHF. New or worsened CHF was reported in 0.4% of 225 patients with supraventricular arrhythmias. There have also been instances of second- (0.5%) or third-degree (0.4%) AV block. Patients have developed sinus bradycardia, sinus pause, or sinus arrest, about 1.2% altogether. The frequency of most of these serious adverse events probably increases with higher trough plasma levels, especially when these trough levels exceed 1 mcg/mL.

There have been rare reports of isolated elevations of serum alkaline phosphatase and isolated elevations of serum transaminase levels. These elevations have been asymptomatic and no cause and effect relationship with Flecainide has been established. In foreign postmarketing surveillance studies, there have been rare reports of hepatic dysfunction including reports of cholestasis and hepatic failure, and extremely rare reports of blood dyscrasias. Although no cause and effect relationship has been established, it is advisable to discontinue Flecainide in patients who develop unexplained jaundice or signs of hepatic dysfunction or blood dyscrasias in order to eliminate Flecainide as the possible causative agent.

Incidence figures for other adverse effects in patients with ventricular arrhythmias are based on a multicenter efficacy study, utilizing starting doses of 200 mg/day with gradual upward titration to 400 mg/day. Patients were treated for an average of 4.7 months, with some receiving up to 22 months of therapy. In this trial, 5.4% of patients discontinued due to non-cardiac adverse effects.

Table 1

The following additional adverse experiences, possibly related to Flecainide therapy and occurring in 1% to less than 3% of patients, have been reported in acute and chronic studies: Body as a Whole -malaise, fever; Cardiovascular -tachycardia, sinus pause or arrest; Gastrointestinal -vomiting, diarrhea, dyspepsia, anorexia; Skin -rash; Visual -diplopia; Nervous System -hypoesthesia, paresthesia, paresis, ataxia, flushing, increased sweating, vertigo, syncope, somnolence, tinnitus; Psychiatric -anxiety, insomnia, depression.

The following additional adverse experiences, possibly related to Flecainide, have been reported in less than 1% of patients: Body as a Whole -swollen lips, tongue and mouth; arthralgia, bronchospasm, myalgia; Cardiovascular -angina pectoris, second-degree and third-degree AV block, bradycardia, hypertension, hypotension; Gastrointestinal -flatulence; Urinary System -polyuria, urinary retention; Hematologic -leukopenia, granulocytopenia, thrombocytopenia; Skin -urticaria, exfoliative dermatitis, pruritus, alopecia; Visual -eye pain or irritation, photophobia, nystagmus; Nervous System -twitching, weakness, change in taste, dry mouth, convulsions, impotence, speech disorder, stupor, neuropathy; Respiratory -pneumonitis/pulmonary infiltration possibly due to chronic Flecainide treatment: Psychiatric -amnesia, confusion, decreased libido, depersonalization, euphoria, morbid dreams, apathy.

For patients with supraventricular arrhythmias, the most commonly reported noncardiac adverse experiences remain consistent with those known for patients treated with Flecainide for ventricular arrhythmias. Dizziness is possibly more frequent in PAF patients.

Flecainide Tablets

In post-myocardial infarction patients with asymptomatic PVCs and non-sustained ventricular tachycardia, Flecainide therapy was found to be associated with a 5.1% rate of death and non-fatal cardiac arrest, compared with a 2.3% rate in a matched placebo group.

Adverse effects reported for Flecainide, described in detail in the WARNINGS section, were new or worsened arrhythmias which occurred in 1% of 108 patients with PSVT and in 7% of 117 patients with PAF; and new or exacerbated ventricular arrhythmias which occurred in 7% of 1330 patients with PVCs, non-sustained or sustained VT. In patients treated with Flecainide for sustained VT, 80% (51/64) of proarrhythmic events occurred within 14 days of the onset of therapy. 198 patients with sustained VT experienced a 13% incidence of new or exacerbated ventricular arrhythmias when dosage was initiated at 200 mg/day with slow upward titration, and did not exceed 300 mg/day in most patients. In some patients, Flecainide treatment has been associated with episodes of unresuscitatable VT or ventricular fibrillation (cardiac arrest). New or worsened CHF occurred in 6.3% of 1046 patients with PVCs, non-sustained or sustained VT. Of 297 patients with sustained VT, 9.1% experienced new or worsened CHF. New or worsened CHF was reported in 0.4% of 225 patients with supraventricular arrhythmias. There have also been instances of second- (0.5%) or third-degree (0.4%) AV block. Patients have developed sinus bradycardia, sinus pause, or sinus arrest, about 1.2% altogether. The frequency of most of these serious adverse events probably increases with higher trough plasma levels, especially when these trough levels exceed 1 mcg/mL.

There have been rare reports of isolated elevations of serum alkaline phosphatase and isolated elevations of serum transaminase levels. These elevations have been asymptomatic and no cause and effect relationship with Flecainide has been established. In foreign postmarketing surveillance studies, there have been rare reports of hepatic dysfunction including reports of cholestasis and hepatic failure, and extremely rare reports of blood dyscrasias. Although no cause and effect relationship has been established, it is advisable to discontinue Flecainide in patients who develop unexplained jaundice or signs of hepatic dysfunction or blood dyscrasias in order to eliminate Flecainide as the possible causative agent.

Incidence figures for other adverse effects in patients with ventricular arrhythmias are based on a multicenter efficacy study, utilizing starting doses of 200 mg/day with gradual upward titration to 400 mg/day. Patients were treated for an average of 4.7 months, with some receiving up to 22 months of therapy. In this trial, 5.4% of patients discontinued due to non-cardiac adverse effects.

Table 1 Most Common Non-Cardiac Adverse Effects in Ventricular Arrhythmia Patients Treated with Flecainide in the Multicenter Study

The following additional adverse experiences, possibly related to Flecainide therapy and occurring in 1% to less than 3% of patients, have been reported in acute and chronic studies: Body as a Whole -malaise, fever; Cardiovascular -tachycardia, sinus pause or arrest; Gastrointestinal -vomiting, diarrhea, dyspepsia, anorexia; Skin -rash; Visual -diplopia; Nervous System -hypoesthesia, paresthesia, paresis, ataxia, flushing, increased sweating, vertigo, syncope, somnolence, tinnitus; Psychiatric -anxiety, insomnia, depression.

The following additional adverse experiences, possibly related to Flecainide, have been reported in less than 1% of patients:

Body as a Whole - swollen lips, tongue and mouth; arthralgia, bronchospasm, myalgia;

Cardiovascular - angina pectoris, second-degree and third-degree AV block, bradycardia, hypertension, hypotension;

Gastrointestinal - flatulence;

Urinary System - polyuria, urinary retention;

Hematologic - leukopenia, granulocytopenia, thrombocytopenia;

Skin - urticaria, exfoliative dermatitis, pruritus, alopecia;

Visual - eye pain or irritation, photophobia, nystagmus;

Nervous System - twitching, weakness, change in taste, dry mouth, convulsions, impotence, speech disorder, stupor, neuropathy;

Respiratory - pneumonitis/pulmonary infiltration possibly due to chronic Flecainide treatment:

Psychiatric - amnesia, confusion, decreased libido, depersonalization, euphoria, morbid dreams, apathy.

For patients with supraventricular arrhythmias, the most commonly reported noncardiac adverse experiences remain consistent with those known for patients treated with Flecainide for ventricular arrhythmias. Dizziness is possibly more frequent in PAF patients.

1

*Dizziness includes reports of dizziness, lightheadedness, faintness, unsteadiness, near syncope, etc

2

†Visual disturbance includes reports of blurred vision, difficulty in focusing, spots before eyes, etc

Side Effects by Body System

General

The Cardiac Arrhythmia Suppression Trial (CAST) revealed significantly higher mortality associated with flecainide in patients with a recent history (more than six days but less than two years prior to study) of myocardial infarction (MI) and non-life-threatening ventricular ectopy relative to placebo (5.1% versus 2.3%). The risk of death relative to placebo in patients with a recent history of Q-wave MI and non-Q-wave MI is 8.7 and 1.7, respectively. Use of flecainide in this context is potentially harmful.

Side effects are more likely when plasma flecainide concentrations are greater than 1.0 mcg/mL.

Cardiovascular

Risk factors for a proarrhythmic effect include underlying congenital or structural heart disease.

A case of "pseudoinfarction" has been reported in which flecainide induced a transient right bundle branch block with a focal block in the septal fibers of the left bundle branch system. An electrocardiogram (ECG) also revealed ST segment elevations and a Q-wave pattern, consistent with septal infarction. The patient did not have a myocardial infarction by enzyme studies, and the ECG abnormalities resolved after discontinuation of flecainide.

One patient with a history of ischemic congestive heart failure, myocardial infarction (MI), and ventricular arrhythmias developed profound cardiogenic shock without evidence of MI or a new or worsened ventricular arrhythmia. The associated serum flecainide concentration was 1.8 mcg/mL.

Cardiovascular side effects including arrhythmias are the most serious side effects. Flecainide may cause or exacerbate arrhythmias in 1% of patients with preexisting paroxysmal supraventricular tachycardia and in 7% of patients with paroxysmal atrial fibrillation. Flecainide may also exacerbate arrhythmias in 7% to 13% of patients with preexisting sustained or nonsustained ventricular arrhythmias.

Flecainide-induced arrhythmias include sinus bradycardia or arrest in 2%, bundle branch blocks in 1%, increased premature ventricular depolarizations in 1%, ventricular tachycardia or fibrillation in 0.5%, and sudden death in 0.2% of patients. New ventricular arrhythmias have been reported in 3.4% of patients.

Flecainide may cause prolongation of the PR, QRS, and corrected QT intervals. Most of the QT interval prolongation is attributable to widening of the QRS complex rather than prolongation of the JT interval. Rare cases of torsades de pointes have been reported.

Exacerbation of congestive heart failure is rare and only occurs in about 0.5% and 9% of patients with preexisting supraventricular arrhythmias and ventricular arrhythmias, respectively. Hypotension is almost exclusively associated with intravenous administration of flecainide.

Nervous system

Nervous system side effects, such as dizziness and visual disturbances (including blurred vision, decreased acuity, and scotomata) occur in 13% to 28% of patients who are taking flecainide doses of 400 mg per day. Transient headaches, asthenia, feelings of a thick tongue or lips, fatigue, paresthesias, and tremors have been reported in 2% to 10% of patients.

Flecainide may exacerbate myasthenia gravis.

At least 6 cases of flecainide-induced peripheral neuropathy (sensory loss) have been reported and it appears to develop after prolonged use ( 2 to 10 years). Following discontinuation of flecainide therapy, symptoms (e.g., lower-extremity weakness and/or paresthesias, gait disturbance) resolved over 3 to 6 months. However, in some cases the neuropathy did not resolve after discontinuation of flecainide.

Gastrointestinal

Gastrointestinal side effects include abdominal pain, nausea, and constipation in 1% to 4% of patients. Diarrhea occurs rarely.

Musculoskeletal

Musculoskeletal side effects including weakness has been reported and may be more likely in patients with underlying muscular disorders.

A 33-year-old woman with atrial fibrillation, mitral valve prolapse, and a congenital muscle fiber disproportion myopathy developed muscle weakness which partially resolved after flecainide dosage reduction and completely resolved after substitution of flecainide with other antiarrhythmic agents.

Ocular

High performance liquid chromatographic analysis of excised corneal deposits in one patient revealed opacities with the same chromatographic characteristics of flecainide.

Ocular side effects are limited to rare cases of corneal deposits.

Genitourinary

Class I antiarrhythmic agents such as flecainide have local anesthetic and anticholinergic properties which may rarely cause urinary retention.

Genitourinary side effects including complaints of impotence are reported in 4% of patients. A case of urinary retention associated with flecainide has been reported.

Respiratory

A case of reversible flecainide-induced pneumonitis was reported in a 61-year-old man with a remote history of pulmonary tuberculosis. A complete infectious disease work-up was negative. Serial bronchial-alveolar lavages and chest radiographs were consistent with a drug-induced process.

Respiratory side effects are extremely rare.

Hematologic

One patient developed leukopenia after 5 months of flecainide therapy. The leukopenia resolved after drug discontinuation and did not recur when flecainide was reinstituted. The leukopenia may have been due to a concurrent viral infection.

Hematologic side effects are extremely rare.

Hepatic

Hepatic side effects including enzyme concentration elevations have been reported in rare cases.

Psychiatric

Psychiatric side effects including paranoid psychosis was reported in a 62-year-old patient receiving flecainide for the treatment of malignant neuropathic pain.

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