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Drug Safety-related Labeling Changes (SrLC)

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RYTHMOL (NDA-019151)

(PROPAFENONE HYDROCHLORIDE)

Safety-related Labeling Changes Approved by FDA Center for Drug Evaluation and Research (CDER)

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11/02/2018 (SUPPL-15)

Approved Drug Label (PDF)

5 Warnings and Precautions

5.1 Proarrhythmic Effects

(Additions and/or revisions are underlined)

Propafenone has caused new or worsened arrhythmias. Such proarrhythmic effects include sudden death and life-threatening ventricular arrhythmias such as ventricular fibrillation, ventricular tachycardia, asystole, and torsade de pointes. It may also worsen premature ventricular contractions or supraventricular arrhythmias, and it may prolong the QT interval. It is therefore essential that each patient given RYTHMOL be evaluated electrocardiographically prior to and during therapy to determine whether the response to RYTHMOL supports continued treatment. Because propafenone prolongs the QRS interval in the electrocardiogram, changes in the QT interval are difficult to interpret.

 In a U.S. uncontrolled, open-label, multicenter trial in subjects with symptomatic supraventricular tachycardia (SVT), 1.9% (9/474) of these subjects experienced ventricular tachycardia (VT) or ventricular fibrillation (VF) during the trial. However, in 4 of the 9 subjects, the ventricular tachycardia was of atrial origin. Six of the 9 subjects that developed ventricular arrhythmias did so within 14 days of onset of therapy. About 2.3% (11/474) of all subjects had a recurrence of SVT during the trial which could have been a change in the subjects’ arrhythmia behavior or could represent a proarrhythmic event. Case reports in patients treated with propafenone for atrial fibrillation/flutter have included increased premature ventricular contractions (PVCs), VT, VF, torsade de pointes, asystole, and death.

Overall in clinical trials with RYTHMOL (which included subjects treated for ventricular arrhythmias, atrial fibrillation/flutter, and PSVT), 4.7% of all subjects had new or worsened ventricular arrhythmia possibly representing a proarrhythmic event (0.7% was an increase in PVCs; 4.0% a worsening or new appearance of VT or VF). Of the subjects who had worsening of VT (4%), 92% had a history of VT and/or VT/VF, 71% had coronary artery disease, and 68% had a prior myocardial infarction. The incidence of proarrhythmia in subjects with less serious or benign arrhythmias, which include subjects with an increase in frequency of PVCs, was 1.6%.

Although most proarrhythmic events occurred during the first week of therapy, late events also were seen and the CAST trial suggests that an increased risk of proarrythmia is present throughout treatment.

In a trial of sustained-release propafenone (RYTHMOL SR), there were too few deaths to assess the long-term risk to patients. There were 5 deaths; 3 in the pooled group for RYTHMOL SR (0.8%), and 2 in the placebo group (1.6%). In the overall database of 8 trials of  RYTHMOL SR and immediate-release RYTHMOL, the mortality rate was 2.5% per year on propafenone and 4.0% per year on placebo. Concurrent use of propafenone with other antiarrhythmic agents has not been well studied.

 

5.4         Drug Interactions: Simultaneous Use with Inhibitors of Cytochrome P450 Isoenzymes 2D6 and 3A4

 (Additions and/or revisions are underlined)

Propafenone is metabolized by CYP2D6, CYP3A4, and CYP1A2 isoenzymes. Approximately 6% of Caucasians in the U.S. population are naturally deficient in CYP2D6 activity and other demographic groups are deficient to a somewhat lesser extent. Drugs that inhibit these CYP pathways (such as desipramine, paroxetine, ritonavir, sertraline for CYP2D6; ketoconazole, erythromycin, saquinavir, and grapefruit juice for CYP3A4; and amiodarone and tobacco smoke for CYP1A2) can be expected to cause increased plasma levels of propafenone.

 

5.5         Use in Patients with a History of Heart Failure

 (Additions and/or revisions are underlined)

Propafenone exerts a negative inotropic activity on the myocardium as well as beta-blockade effects and may provoke overt heart failure.

In clinical trial experience with RYTHMOL, new or worsened congestive heart failure (CHF) has been reported in 3.7% of subjects with ventricular arrhythmia; of those 0.9% were        considered probably or definitely related to propafenone HCl. Of the subjects with CHF probably related to propafenone, 80% had pre-existing heart failure and 85% had coronary artery disease. CHF attributable to propafenone HCl developed rarely (less than 0.2%) in subjects with ventricular arrhythmia who had no previous history of CHF. CHF occurred in 1.9% of subjects studied with PAF or PSVT.

In a U.S. trial of RYTHMOL SR in subjects with symptomatic AF, heart failure was reported in 4 (1.0%) subjects receiving RYTHMOL SR (all doses) compared with 1 (0.8%) subject receiving placebo.


5.9       Use in Patients with Hepatic Dysfunction

 (Additions and/or revisions are underlined)

Propafenone is highly metabolized by the liver. Severe liver dysfunction increases the bioavailability of propafenone to approximately 70% compared with 3% to 40% in patients with normal liver function. In 8 subjects with moderate to severe liver disease, the mean half-life was approximately 9 hours. Increased bioavailability of propafenone in these patients may result in excessive accumulation. Carefully monitor patients with impaired hepatic function for excessive pharmacological effects.

6 Adverse Reactions

6.1 Clinical Trials Experience

(Additions and/or revisions are underlined)

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in the clinical trials of another drug and may not reflect the rates observed in practice.

Adverse reactions associated with RYTHMOL occur most frequently in the gastrointestinal, cardiovascular, and central nervous systems. About 20% of subjects treated with RYTHMOL have discontinued treatment because of adverse reactions.

 reactions reported for greater than 1.5% of 474 subjects with SVT who received RYTHMOL in U.S. clinical trials are presented in Table 1 by incidence and percent discontinuation, reported to the nearest percent.

Table 1:. Adverse Reactions Reported for > 1.5% of Subjects with Supraventricular Tachycardia

….

In controlled trials in subjects with ventricular arrhythmia, the most common reactions reported for RYTHMOL and more frequent than on placebo were unusual taste, dizziness, first-degree AV block, intraventricular conduction delay, nausea and/or vomiting, and constipation.

Headache was relatively common also, but was not increased compared with placebo. Other reactions reported more frequently than on placebo or comparator and not already reported elsewhere included anxiety, angina, second-degree AV block, bundle branch block, loss of balance, congestive heart failure, and dyspepsia.

Adverse reactions reported for greater than or equal to 1% of 2,127 subjects with ventricular arrhythmia who received propafenone in U.S. clinical trials were evaluated by daily dose. The most common adverse reactions appeared dose-related (but note that most subjects spent more time at the larger doses), especially dizziness, nausea and/or vomiting, unusual taste, constipation, and blurred vision. Some less common reactions may also have been dose-related such as first-degree AV block, congestive heart failure, dyspepsia, and weakness. Other adverse reactions included rash, syncope, chest pain, abdominal pain, ataxia, and hypotension.

….

8 Use in Specific Populations

8.1 Pregnancy

(Pregnancy and Lactation Labeling Rule (PLLR)revision)

Risk Summary

There are no studies of RYTHMOL in pregnant women. Available data from published case reports and several decades of postmarketing experience with use of RYTHMOL in pregnancy have not identified any drug-associated risks of miscarriage, birth defects, or adverse maternal or fetal outcomes. Untreated arrhythmias during pregnancy may pose a risk to the pregnant woman and fetus. Propafenone and its metabolite, 5-OH-propafenone, cross the placenta in humans. In animal studies, propafenone was not teratogenic. At maternally toxic doses (ranging from 2 to 6 times the maximum recommended human dose [MRHD]), there was evidence of adverse developmental outcomes when administered to pregnant rabbits and rats during organogenesis or when administered to pregnant rats during mid-gestation through weaning of their offspring .

The estimated background risks of major birth defects and miscarriage for the indicated populations are unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.

Clinical Considerations

Disease-associated maternal and/or embryo/fetal risk: The incidence of VT is increased and may be more symptomatic during pregnancy. Ventricular arrhythmias most often occur in pregnant women with underlying cardiomyopathy, congenital heart disease, valvular heart disease, or mitral valve prolapse. Breakthrough arrhythmias may also occur during pregnancy, as therapeutic treatment levels may be difficult to maintain due to the increased volume of distribution and increased drug metabolism inherent in the pregnant state.

Fetal/Neonatal Adverse Reactions: Propafenone and its metabolite have been shown to cross the placenta. Adverse reactions such as fetal/neonatal arrhythmias have been associated with the use of other antiarrhythmic agents by pregnant women. Fetal/neonatal monitoring for signs and symptoms of arrhythmia is recommended during and after treatment of pregnant women with propafenone.

Labor or Delivery: Risk of arrhythmias may increase during labor and delivery. Patients treated with RYTHMOL should be monitored continuously for arrhythmias during labor and delivery.

Data

Propafenone has been shown to cause embryo-fetal mortality in rabbits and rats when given orally during organogenesis at maternally toxic doses of 150 mg/kg/day (rabbit: maternal mortality, decreased body weight gain and food consumption at approximately 3 times the MRHD on a mg/m2 basis) and 600 mg/kg/day (rat: maternal decreased body weight gain and food consumption at approximately 6 times the MRHD on a mg/m2 basis). In addition, a maternally toxic dose of 600 mg/kg/day (approximately 6 times the MRHD on a mg/m2 basis) also caused decreased fetal weights in rats. Increased placental weights and delayed ossification occurred in rabbits at a dose of 30 mg/kg/day (less than the MRHD on a mg/m2 basis) in the absence of maternal toxicity. No adverse developmental outcomes in the absence of maternal toxicity were seen following oral doses of 15 mg/kg/day to rabbits or up to 270 mg/kg/day to rats administered during organogenesis (equivalent to 0.3 times or approximately 3 times the MRHD on a mg/m2 basis, respectively). In an oral study, female rats received propafenone up to 500 mg/kg/day from mid-gestation through weaning At 90 mg/kg/day (equivalent to the MRHD on a mg/m2 basis), there were no adverse developmental outcomes in the absence of maternal toxicity. However, doses greater than or equal to 180 mg/kg/day (2 or more times the MRHD on a mg/m2 basis) produced increases in maternal deaths and resulted in reductions in neonatal survival, body weight gain, and delayed development in the presence of maternal toxicity.


8.2       Lactation

(Pregnancy and Lactation Labeling Rule (PLLR) revision)

Risk Summary

Propafenone and its active metabolite, 5-OH-propafenone, are present in human milk, but the levels are likely to be low. There are no data on the effects of propafenone on the breastfed infant or the effects on milk production.

The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for propafenone and any potential adverse effects on the breastfed infant from propafenone or from the underlying maternal condition.


8.3       Females and Males of Reproductive Potential

(Pregnancy and Lactation Labeling Rule (PLLR)revision)

Infertility

Males: Based on human and animal studies, RYTHMOL may transiently impair spermatogenesis in males. Evaluation of the effects on spermatogenesis was performed in 11 healthy males given oral propafenone 300 mg b.i.d. for 4 days, which was then increased to 300 mg t.i.d. for an additional 4 days. Study findings included a 28% reduction in semen sample volume on Treatment Day 8 and a 27% reduction in sperm count 64 days after treatment (both values remained within the laboratories normal reference range). These effects were not seen in follow- up visits up to 120 days after treatment. Reversible decreases in spermatogenesis have been demonstrated in monkeys, dogs, and rabbits after lethal or near-lethal intravenous doses of propafenone.

 

8.5       Geriatric Use

(Additions and/or revisions are underlined)

Clinical trials of RYTHMOL did not include sufficient numbers of subjects aged 65 and older to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger subjects. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

17 PCI/PI/MG (Patient Counseling Information/Patient Information/Medication Guide)

17 PATIENT COUNSELING INFORMATION

(Subsection has been revised)

Advise the patient to read the FDA-approved patient labeling (Patient Information).

  • Instruct patients to notify their healthcare providers of any change in over-the-counter, prescription, and supplement use.

  • Instruct patients to report symptoms that may be associated with altered electrolyte balance, such as excessive or prolonged diarrhea, sweating, vomiting, or loss of appetite or thirst.

  • Instruct patients not to double the next dose if a dose is missed. The next dose should be taken at the usual time.

 

Other

Patient Information

(Additions and/or revisions are underlined)

 

What should I tell my doctor before taking RYTHMOL? Before you take RYTHMOL, tell your doctor if you:

    • have liver or kidney problems

    • have breathing problems

    • have symptoms including diarrhea, sweating, vomiting, or loss of appetite or thirst that are severe. These symptoms may be a sign of abnormal electrolyte levels in your blood.

    • have myasthenia gravis

    • have lupus erythematosus

    • have been told you have or had an abnormal blood test called Antinuclear Antibody Test or ANA Test

    • have any other medical conditions

    • are pregnant or plan to become pregnant

    • are breastfeeding or plan to breastfeed. RYTHMOL can pass into your milk. You and your doctor should discuss the best way to feed your baby during this time.