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.
…