WARNINGS
Included as part of the PRECAUTIONS section.
PRECAUTIONS
Addiction, Abuse, And Misuse
BUNAVAIL contains buprenorphine, a Schedule III
controlled substance that can be abused in a manner similar to other opioids,
legal or illicit. Prescribe and dispense buprenorphine with appropriate
precautions to minimize risk of misuse, abuse, or diversion, and ensure
appropriate protection from theft, including in the home. Clinical monitoring
appropriate to the patient's level of stability is essential. Multiple refills
should not be prescribed early in treatment or without appropriate patient
follow-up visits [see Drug Abuse And Dependence].
Risk Of Respiratory And Central Nervous System (CNS)
Depression
Buprenorphine has been associated with life-threatening
respiratory depression and death. Many, but not all, post-marketing reports
regarding coma and death involved misuse by self-injection or were associated
with the concomitant use of buprenorphine and benzodiazepines or other CNS
depressants including alcohol. Warn patients of the potential danger of
self-administration of benzodiazepines or other CNS depressants while under
treatment with BUNAVAIL [see Managing Risks From Concomitant Use Of Benzodiazepines Or
Other CNS Depressants and, DRUG
INTERACTIONS].
Use BUNAVAIL with caution in patients with compromised
respiratory function (e.g., chronic obstructive pulmonary disease, cor
pulmonale, decreased respiratory reserve, hypoxia, hypercapnia, or pre-existing
respiratory depression).
Managing Risks From Concomitant Use Of Benzodiazepines Or
Other CNS Depressants
Concomitant use of buprenorphine and benzodiazepines or
other CNS depressants increases the risk of adverse reactions including
overdose and death. Medication-assisted treatment of opioid use disorder,
however, should not be categorically denied to patients taking these drugs.
Prohibiting or creating barriers to treatment can pose an
even greater risk of morbidity and mortality due to the opioid use disorder
alone.
As a routine part of orientation to buprenorphine
treatment, educate patients about the risks of concomitant use of
benzodiazepines, sedatives, opioid analgesics, and alcohol.
Develop strategies to manage use of prescribed or illicit
benzodiazepines or other CNS depressants at initiation of buprenorphine
treatment, or if it emerges as a concern during treatment. Adjustments to
induction procedures and additional monitoring may be required. There is no
evidence to support dose limitations or arbitrary caps of buprenorphine as a
strategy to address benzodiazepine use in buprenorphine-treated patients.
However, if a patient is sedated at the time of buprenorphine dosing, delay or
omit the buprenorphine dose if appropriate.
Cessation of benzodiazepines or other CNS depressants is
preferred in most cases of concomitant use. In some cases, monitoring in a
higher level of care for taper may be appropriate. In others, gradually
tapering a patient off of a prescribed benzodiazepine or other CNS depressant
or decreasing to the lowest effective dose may be appropriate.
For patients in buprenorphine treatment, benzodiazepines
are not the treatment of choice for anxiety or insomnia. Before co-prescribing
benzodiazepines, ensure that patients are appropriately diagnosed and consider
alternative medications and non-pharmacologic treatments to address anxiety or
insomnia. Ensure that other healthcare providers prescribing benzodiazepines or
other CNS depressants are aware of the patient's buprenorphine treatment and
coordinate care to minimize the risks associated with concomitant use.
In addition, take measures to confirm that patients are
taking their medications as prescribed and are not diverting or supplementing
with illicit drugs. Toxicology screening should test for prescribed and illicit
benzodiazepines [see DRUG INTERACTIONS].
Unintentional Pediatric Exposure
Buprenorphine can cause severe, possibly fatal,
respiratory depression in children who are accidentally exposed to it. Store
buprenorphine-containing medications safely out of the sight and reach of
children and destroy any unused medication appropriately [see Patient
Counseling Information].
Neonatal Opioid Withdrawal Syndrome
Neonatal opioid withdrawal syndrome (NOWS) is an expected
and treatable outcome of prolonged use of opioids during pregnancy, whether
that use is medically-authorized or illicit. Unlike opioid withdrawal syndrome
in adults, NOWS may be life-threatening if not recognized and treated in the
neonate. Healthcare professionals should observe newborns for signs of NOWS and
manage accordingly [see Use In Specific Populations].
Advise pregnant women receiving opioid addiction
treatment with BUNAVAIL of the risk of neonatal opioid withdrawal syndrome and
ensure that appropriate treatment will be available [see Use In Specific
Populations]. This risk must be balanced against the risk of untreated
opioid addiction which often results in continued or relapsing illicit opioid
use and is associated with poor pregnancy outcomes. Therefore, prescribers
should discuss the importance and benefits of management of opioid addiction
throughout pregnancy.
Adrenal Insufficiency
Cases of adrenal insufficiency have been reported with
opioid use, more often following greater than one month of use. Presentation of
adrenal insufficiency may include non-specific symptoms and signs including
nausea, vomiting, anorexia, fatigue, weakness, dizziness, and low blood pressure.
If adrenal insufficiency is diagnosed, treat with physiologic replacement doses
of corticosteroids. Wean the patient off of the opioid to allow adrenal
function to recover and continue corticosteroid treatment until adrenal
function recovers. Other opioids may be tried as some cases reported use of a
different opioid without recurrence of adrenal insufficiency. The information
available does not identify any particular opioids as being more likely to be
associated with adrenal insufficiency.
Risk Of Opioid Withdrawal With Abrupt Discontinuation
Buprenorphine is a partial agonist at the mu-opioid
receptor and chronic administration produces physical dependence of the opioid
type, characterized by withdrawal signs and symptoms upon abrupt
discontinuation or rapid taper. The withdrawal syndrome is typically milder
than seen with full agonists and may be delayed in onset. When discontinuing
BUNAVAIL, gradually taper the dosage [see DOSAGE AND ADMINISTRATION].
Risk Of Hepatitis, Hepatic Events
Cases of cytolytic hepatitis and hepatitis with jaundice
have been observed in individuals receiving buprenorphine in clinical trials
and through post-marketing adverse event reports. The spectrum of abnormalities
ranges from transient asymptomatic elevations in hepatic transaminases to case
reports of death, hepatic failure, hepatic necrosis, hepatorenal syndrome, and
hepatic encephalopathy. In many cases, the presence of pre-existing liver
enzyme abnormalities, infection with hepatitis B or hepatitis C virus,
concomitant usage of other potentially hepatotoxic drugs, and ongoing injecting
drug use may have played a causative or contributory role. In other cases,
insufficient data were available to determine the etiology of the abnormality.
Withdrawal of buprenorphine has resulted in amelioration of acute hepatitis in
some cases; however, in other cases no dose reduction was necessary. The
possibility exists that buprenorphine had a causative or contributory role in
the development of the hepatic abnormality in some cases. Liver function tests
prior to initiation of treatment are recommended to establish a baseline.
Periodic monitoring of liver function during treatment is also recommended. A
biological and etiological evaluation is recommended when a hepatic event is
suspected. Depending on the case, BUNAVAIL may need to be carefully
discontinued to prevent withdrawal signs and symptoms and a return by the
patient to illicit drug use, and strict monitoring of the patient should be
initiated.
Hypersensitivity Reactions
Cases of hypersensitivity to buprenorphine and naloxone
containing products have been reported both in clinical trials and in
post-marketing experience. Cases of bronchospasm, angioneurotic edema, and
anaphylactic shock have been reported. The most common signs and symptoms
include rashes, hives and pruritus. A history of hypersensitivity to
buprenorphine or naloxone is a contraindication to the use of BUNAVAIL.
Precipitation Of Opioid Withdrawal Signs And Symptoms
Because it contains naloxone, BUNAVAIL is likely to
produce withdrawal signs and symptoms if misused parenterally by individuals
dependent on full opioid agonists such as heroin, morphine, or methadone.
Because of the partial agonist properties of buprenorphine, BUNAVAIL may
precipitate opioid withdrawal signs and symptoms in such persons if
administered buccally before the agonist effects of the opioid have subsided.
Risk Of Overdose In Opioid Naïve Patients
There have been reported deaths of opioid naïve
individuals who received a 2 mg dose of buprenorphine, smaller than the lowest
strength of BUNAVAIL, for analgesia. BUNAVAIL is not appropriate as an
analgesic.
Use In Patients With Impaired Hepatic Function
Buprenorphine/naloxone products are not recommended in
patients with severe hepatic impairment and may not be appropriate for patients
with moderate hepatic impairment. The doses of buprenorphine and naloxone in
this fixed-dose combination product cannot be individually titrated, and
hepatic impairment results in a reduced clearance of naloxone to a much greater
extent than buprenorphine. Therefore, patients with severe hepatic impairment
will be exposed to substantially higher levels of naloxone than patients with
normal hepatic function. This may result in an increased risk of precipitated
withdrawal at the beginning of treatment (induction) and may interfere with
buprenorphine's efficacy throughout treatment. In patients with moderate
hepatic impairment, the differential reduction of naloxone clearance compared
to buprenorphine clearance is not as great as in subjects with severe hepatic
impairment. However, buprenorphine/naloxone products are not recommended for
initiation of treatment (induction) in patients with moderate hepatic
impairment due to the increased risk of precipitated withdrawal.
Buprenorphine/naloxone products may be used with caution for maintenance
treatment in patients with moderate hepatic impairment who have initiated
treatment on a buprenorphine product without naloxone. However, patients should
be carefully monitored and consideration given to the possibility of naloxone
interfering with buprenorphine's efficacy [see Use In Specific Populations].
Impairment Of Ability To Drive Or Operate Machinery
BUNAVAIL may impair the mental or physical abilities
required for the performance of potentially dangerous tasks such as driving a
car or operating machinery, especially during treatment induction and dose
adjustment. Caution patients about driving or operating hazardous machinery
until they are reasonably certain that BUNAVAIL therapy does not adversely
affect their ability to engage in such activities.
Orthostatic Hypotension
Like other opioids, BUNAVAIL may produce orthostatic
hypotension in ambulatory patients.
Elevation Of Cerebrospinal Fluid Pressure
Buprenorphine, like other opioids, may elevate
cerebrospinal fluid pressure and should be used with caution in patients with
head injury, intracranial lesions, and other circumstances when cerebrospinal
pressure may be increased. Buprenorphine can produce miosis and changes in the
level of consciousness that may interfere with patient evaluation.
Elevation Of Intracholedochal Pressure
Buprenorphine has been shown to increase intracholedochal
pressure, as do other opioids, and thus should be administered with caution to
patients with dysfunction of the biliary tract.
Effects In Acute Abdominal Conditions
As with other opioids, buprenorphine may obscure the
diagnosis or clinical course of patients with acute abdominal conditions.
Patient Counseling Information
Advise patients to read the FDA-approved patient labeling
(Medication Guide).
Safe Use
Before initiating treatment with BUNAVAIL, explain the
points listed below to caregivers and patients. Instruct patients to read the
Medication Guide each time BUNAVAIL is dispensed because new information may be
available.
- BUNAVAIL must be administered whole. Advise patients not
to chew or swallow BUNAVAIL.
- Inform patients and caregivers that potentially fatal
additive effects may occur if BUNAVAIL is used with benzodiazepines or other
CNS depressants, including alcohol. Counsel patients that such medications
should not be used concomitantly unless supervised by a healthcare provider [see WARNINGS AND PRECAUTIONS, DRUG INTERACTIONS].
- Advise patients that BUNAVAIL contains an opioid that can
be a target for people who abuse prescription medications or street drugs, to
keep their films in a safe place, and to protect them from theft.
- Instruct patients to keep BUNAVAIL in a secure place, out
of the sight and reach of children. Accidental or deliberate ingestion by a
child may cause respiratory depression that can result in death. Advise
patients that if a child is exposed to BUNAVAIL, medical attention should be
sought immediately.
- Inform patients that opioids could cause a rare but
potentially life-threatening condition resulting from concomitant
administration of serotonergic drugs. Warn patients of the symptoms of
serotonin syndrome and to seek medical attention right away if symptoms
develop. Instruct patients to inform their healthcare providers if they are
taking, or plan to take serotonergic medications [see DRUG INTERACTIONS].
- Inform patients that opioids could cause adrenal
insufficiency, a potentially life-threatening condition. Adrenal insufficiency
may present with non-specific symptoms and signs such as nausea, vomiting,
anorexia, fatigue, weakness, dizziness, and low blood pressure. Advise patients
to seek medical attention if they experience a constellation of these symptoms [see WARNINGS AND PRECAUTIONS].
- Advise patients never to give BUNAVAIL to anyone else,
even if he or she has the same signs and symptoms. It may cause harm or death.
- Advise patients that selling or giving away this
medication is against the law.
- Caution patients that BUNAVAIL may impair the mental or
physical abilities required for the performance of potentially dangerous tasks
such as driving or operating machinery. Caution should be taken especially
during drug induction and dose adjustment and until individuals are reasonably
certain that buprenorphine therapy does not adversely affect their ability to
engage in such activities [see WARNINGS AND PRECAUTIONS].
- Advise patients that they should not change the dosage of
BUNAVAIL without consulting their healthcare provider.
- Advise patients to take BUNAVAIL once a day.
- Advise patients that if they miss a dose of BUNAVAIL they
should take it as soon as they remember. If it is almost time for the next
dose, they should skip the missed dose and take the next dose at the regular
time.
- Inform patients that BUNAVAIL can cause drug dependence
and that withdrawal signs and symptoms may occur when the medication is
discontinued.
- Advise patients seeking to discontinue treatment with buprenorphine
for opioid dependence to work closely with their healthcare provider on a
tapering schedule and inform them of the potential to relapse to illicit drug
use associated with discontinuation of opioid agonist/partial agonist
medication-assisted treatment.
- Advise patients that, like other opioids, BUNAVAIL may
produce orthostatic hypotension in ambulatory individuals [see WARNINGS AND
PRECAUTIONS].
- Advise patients to inform their healthcare provider if
any other prescription medications, over-the-counter medications, or herbal
preparations are prescribed or currently being used [see DRUG INTERACTIONS].
- Advise women that if they are pregnant while being
treated with BUNAVAIL, the baby may have signs of withdrawal at birth and that
appropriate treatment is available [see WARNINGS AND PRECAUTIONS, Use
In Specific Populations].
- Inform patients that chronic use of opioids may cause
reduced fertility. It is not known whether these effects on fertility are
reversible [see Nonclinical Toxicology].
- Advise women who are breastfeeding to monitor the infant
for drowsiness and difficulty breathing [see Use In Specific Populations].
- Advise patients to inform their family members that, in
the event of emergency, the treating healthcare provider or emergency room
staff should be informed that the patient is physically dependent on an opioid
and that the patient is being treated with BUNAVAIL buccal films.
Disposal Of Unused BUNAVAIL
Unused BUNAVAIL buccal films should be disposed of as
soon as they are no longer needed. To dispose of the unused BUNAVAIL films:
- Remove the BUNAVAIL film from its foil package.
- Drop the BUNAVAIL film into the toilet.
- Repeat steps 1 and 2 for each BUNAVAIL film. Flush the
toilet after all unneeded films have been deposited into the toilet.
Do not flush the BUNAVAIL films in their foil packages,
or cartons down the toilet [see HOW SUPPLIED/Storage And Handling].
In the event that additional assistance is needed in
disposing of excess unusable films that remain in the home, call the toll-free
number (1-800-469-0261) or seek assistance from the local DEA office.
Nonclinical Toxicology
Carcinogenesis, Mutagenesis, Impairment Of Fertility
BUNAVAIL has been shown to have differences in
bioavailability compared to buprenorphine/naloxone-containing sublingual
products. The exposure margins listed below are based on body surface area
comparisons (mg/m²) to the recommended human sublingual dose of 16 mg
buprenorphine from Suboxone, which is equivalent to a recommended human buccal
dose (RHD) of 8.4 mg buprenorphine from BUNAVAIL.
Carcinogenicity
A carcinogenicity study of buprenorphine/naloxone (4:1
ratio of the free bases) was performed in Alderley Park rats.
Buprenorphine/naloxone was administered in the diet at doses of approximately
7, 31, and 123 mg/kg/day for 104 weeks (estimated buprenorphine exposure was approximately
4, 18, and 44 times the Recommended Human Dose -RHD based on buprenorphine AUC
comparisons). A statistically significant increase in Leydig cell adenomas was
observed in all dose groups. No other drug-related tumors were noted.
Carcinogenicity studies of buprenorphine were conducted
in Sprague-Dawley rats and CD-1 mice. Buprenorphine was administered in the
diet to rats at doses of 0.6, 5.5, and 56 mg/kg/day (estimated exposure was
approximately 0.4, 3, and 35 times the RHD) for 27 months. As in the
buprenorphine/naloxone carcinogenicity study in rat, statistically significant
dose-related increases in Leydig cell tumors occurred. In an 86-week study in
CD-1 mice, buprenorphine was not carcinogenic at dietary doses up to 100
mg/kg/day (estimated buprenorphine exposure was approximately 30 times the
RHD).
Mutagenicity
The 4:1 combination of buprenorphine and naloxone was not
mutagenic in a bacterial mutation assay (Ames test) using four strains of S.
typhimurium and two strains of E. coli. The combination was not clastogenic in
an in vitro cytogenetic assay in human lymphocytes or in an IV micronucleus
test in the rat.
Buprenorphine was studied in a series of tests utilizing
gene, chromosome, and DNA interactions in both prokaryotic and eukaryotic
systems. Results were negative in yeast (S. cerevisiae) for recombinant, gene
convertant, or forward mutations; negative in Bacillus subtilis “rec” assay,
negative for clastogenicity in CHO cells, Chinese hamster bone marrow and
spermatogonia cells, and negative in the mouse lymphoma L5178Y assay.
Results were equivocal in the Ames test: negative in
studies in two laboratories, but positive for frame shift mutation at a high
dose (5 mg/plate) in a third study. Results were positive in the Green-Tweets (E.coli)
survival test, positive in a DNA synthesis inhibition (DSI) test with
testicular tissue from mice, for both in vivo and in vitro incorporation of [3H]thymidine,
and positive in unscheduled DNA synthesis (UDS) test using testicular cells
from mice.
Impairment Of Fertility
Dietary administration of buprenorphine in the rat at
dose levels of 500 ppm or greater (equivalent to approximately 47 mg/kg/day or
greater; estimated exposure approximately 28 times the RHD) produced a
reduction in fertility demonstrated by reduced female conception rates. A
dietary dose of 100 ppm (equivalent to approximately 10 mg/kg/day; estimated
exposure approximately 6 times the RHD) had no adverse effect on fertility.
Use In Specific Populations
Pregnancy
Risk Summary
The data on use of buprenorphine, one of the active
ingredients in BUNAVAIL, in pregnancy, are limited; however, these data do not
indicate an increased risk of major malformations specifically due to
buprenorphine exposure. There are limited data from randomized clinical trials
in women maintained on buprenorphine that were not designed appropriately to
assess the risk of major malformations [see Data]. Observational studies
have reported on congenital malformations among buprenorphine-exposed pregnancies,
but were also not designed appropriately to assess the risk of congenital
malformations specifically due to buprenorphine exposure [see Data]. The
extremely limited data on sublingual naloxone exposure in pregnancy are not
sufficient to evaluate a drug-associated
risk.
Reproductive and developmental studies in rats and
rabbits identified adverse events at clinically relevant and higher doses.
Embryofetal death was observed in both rats and rabbits administered
buprenorphine during the period of organogenesis at doses approximately 6 and
0.3 times, respectively, the human sublingual dose of 16 mg/day of
buprenorphine (equivalent to 8.4 mg/1.4 mg BUNAVAIL). Pre-and postnatal
development studies in rats demonstrated increased neonatal deaths at 0.3 times
and above, and dystocia at approximately 3 times, the human sublingual dose of
16 mg/day of buprenorphine (equivalent to 8.4 mg/1.4 mg BUNAVAIL). No clear
teratogenic effects were seen when buprenorphine was administered during
organogenesis with a range of doses equivalent to or greater than the human
sublingual dose of 16 mg/day of buprenorphine (equivalent to 8.4 mg/1.4 mg
BUNAVAIL). However, increases in skeletal abnormalities were noted in rats and
rabbits administered buprenorphine daily during organogenesis at doses
approximately 0.6 times and approximately equal to the human sublingual dose of
16 mg/day of buprenorphine (equivalent to 8.4 mg/1.4 mg BUNAVAIL),
respectively. In a few studies, some events such as acephalus and omphalocele
were also observed but these findings were not clearly treatment-related [see Data].
Based on animal data, advise pregnant women of the potential risk to a fetus.
The estimated background risk of major birth defects and
miscarriage for the indicated population is unknown. All pregnancies have a
background risk of birth defects, 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 2-4% and 15-20%, respectively.
Clinical Considerations
Disease-Associated Maternal And Embryo-Fetal Risk
Untreated opioid addiction in pregnancy is associated
with adverse obstetrical outcomes such as low birth weight, preterm birth, and
fetal death. In addition, untreated opioid addiction often results in continued
or relapsing illicit opioid use.
Dose Adjustment During Pregnancy And The Postpartum
Period
Dosage adjustments of buprenorphine may be required
during pregnancy, even if the patient was maintained on a stable dose prior to
pregnancy. Withdrawal signs and symptoms should be monitored closely and the
dose adjusted as necessary.
Fetal/Neonatal Adverse Reactions
Neonatal opioid withdrawal syndrome may occur in newborn
infants of mothers who are receiving treatment with BUNAVAIL.
Neonatal opioid withdrawal syndrome presents as
irritability, hyperactivity and abnormal sleep pattern, high pitched cry,
tremor, vomiting, diarrhea, and/or failure to gain weight. Signs of neonatal
withdrawal usually occur in the first days of birth. The duration and severity
of neonatal opioid withdrawal syndrome may vary. Observe newborns for signs of
neonatal opioid withdrawal syndrome and manage accordingly [see WARNINGS AND
PRECAUTIONS].
Labor Or Delivery
Opioid-dependent
women on buprenorphine maintenance therapy may require additional analgesia
during labor.
Data
Human Data
Studies have been conducted to evaluate neonatal outcomes
in women exposed to buprenorphine during pregnancy. Limited data from trials,
observational studies, case series, and case reports on buprenorphine use in
pregnancy do not indicate an increased risk of major malformations specifically
due to buprenorphine. Several factors may complicate the interpretation of
investigations of the children of women who take buprenorphine during
pregnancy, including maternal use of illicit drugs, late presentation for
prenatal care, infection, poor compliance, poor nutrition, and psychosocial
circumstances. Interpretation of data is complicated further by the lack of
information on untreated opioid-dependent pregnant women, who would be the most
appropriate group for comparison. Rather, women on another form of opioid
medication-assisted treatment or women in the general population are generally
used as the comparison group. However, women in these comparison groups may be
different from women prescribed buprenorphine-containing products with respect
to maternal factors that may lead to poor pregnancy outcomes.
In a multicenter, double-blind, randomized, controlled
trial [Maternal Opioid Treatment: Human Experimental Research (MOTHER)]
designed primarily to assess neonatal opioid withdrawal effects,
opioid-dependent pregnant women were randomized to buprenorphine (n=86) or
methadone (n=89) treatment, with enrollment at an average gestational age of
18.7 weeks in both groups. A total of 28 of the 86 women in the buprenorphine
group (33%) and 16 of the 89 women in the methadone group (18%) discontinued
treatment before the end of pregnancy.
Among women who remained in treatment until delivery,
there was no difference between buprenorphine-treated and methadone-treated
groups in the number of neonates requiring NOWS treatment or in the peak
severity of NOWS. Buprenorphine-exposed neonates required less morphine (mean
total dose, 1.1 mg vs. 10.4 mg), had shorter hospital stays (10.0 days vs. 17.5
days), and shorter duration of treatment for NOWS (4.1 days vs. 9.9 days)
compared to the methadone-exposed group. There were no differences between
groups in other primary outcomes (neonatal head circumference) or secondary
outcomes (weight and length at birth, preterm birth, gestational age at
delivery, and 1-minute and 5-minute Apgar scores), or in the rates of maternal
or neonatal adverse events. The outcomes among mothers who discontinued
treatment before delivery and may have relapsed to illicit opioid use are not
known. Because of the imbalance in discontinuation rates between the
buprenorphine and methadone groups, the study findings are difficult to
interpret.
Animal Data
BUNAVAIL has been shown to have differences in
bioavailability compared to buprenorphine/naloxone-containing sublingual
products. The exposure margins listed below are based on body surface area
comparisons (mg/m²) to the recommended human sublingual dose of 16 mg
buprenorphine from Suboxone sublingual tablets (equivalent to 8.4 mg/1.4 mg
BUNAVAIL).
Effects on embryo-fetal development were studied in
Sprague-Dawley rats and Russian white rabbits following oral (1:1) and
intramuscular (IM) (3:2) administration of mixtures of buprenorphine and
naloxone during the period of organogenesis. Following oral administration to
rats, no teratogenic effects were observed at buprenorphine doses up to 250
mg/kg/day (estimated exposure approximately 150 times the human sublingual dose
of 16 mg) in the presence of maternal toxicity (mortality).
Following oral administration to rabbits, no teratogenic
effects were observed at buprenorphine doses up to 40 mg/kg/day (estimated exposure
approximately 50 times the human sublingual dose of 16 mg) in the absence of
clear maternal toxicity. No definitive drug-related teratogenic effects were
observed in rats and rabbits at IM doses up to 30 mg/kg/day (estimated exposure
approximately 20 times and 35 times, respectively, the human sublingual dose of
16 mg). Maternal toxicity resulting in mortality was noted in these studies in
both rats and rabbits. Acephalus was observed in one rabbit fetus from the
low-dose group and omphalocele was observed in two rabbit fetuses from the same
litter in the mid-dose group; no findings were observed in fetuses from the
high-dose group. Maternal toxicity was seen in the high-dose group but not at
the lower doses where the findings were observed. Following oral administration
of buprenorphine to rats, dose-related post-implantation losses, evidenced by
increases in the numbers of early resorptions with consequent reductions in the
numbers of fetuses, were observed at doses of 10 mg/kg/day or greater (estimated
exposure approximately 6 times the human sublingual dose of 16 mg).
In the rabbit, increased post-implantation losses
occurred at an oral dose of 40 mg/kg/day. Following IM administration in the
rat and the rabbit, post-implantation losses, as evidenced by decreases in live
fetuses and increases in resorptions, occurred at 30 mg/kg/day.
Buprenorphine was not teratogenic in rats or rabbits
after IM or subcutaneous (SC) doses up to 5 mg/kg/day (estimated exposure was
approximately 3 and 6 times, respectively, the human sublingual dose of 16 mg),
after IV doses up to 0.8 mg/kg/day (estimated exposure was approximately 0.5
times and equal to, respectively, the human sublingual dose of 16 mg), or after
oral doses up to 160 mg/kg/day in rats (estimated exposure was approximately 95
times the human sublingual dose of 16 mg) and 25 mg/kg/day in rabbits
(estimated exposure was approximately 30 times the human sublingual dose of 16
mg). Significant increases in skeletal abnormalities (e.g., extra thoracic
vertebra or thoraco-lumbar ribs) were noted in rats after SC administration of
1 mg/kg/day and up (estimated exposure was approximately 0.6 times the human
sublingual dose of 16 mg) but were not observed at oral doses up to 160
mg/kg/day.
Increases in skeletal abnormalities in rabbits after IM
administration of 5 mg/kg/day (estimated exposure was approximately 6 times the
human sublingual dose of 16 mg) or oral administration of 1 mg/kg/day or
greater (estimated exposure was approximately equal to the human sublingual
dose of 16 mg) were not statistically significant.
In rabbits, buprenorphine produced statistically
significant pre-implantation losses at oral doses of 1 mg/kg/day or greater and
post-implantation losses that were statistically significant at IV doses of 0.2
mg/kg/day or greater (estimated exposure approximately 0.3 times the human
sublingual dose of 16 mg). No maternal toxicity was noted at doses causing
post-implantation loss in this study.
Dystocia was noted in pregnant rats treated
intramuscularly with buprenorphine during gestation and lactation at 5
mg/kg/day (approximately 3 times the human sublingual dose of 16 mg).
Fertility, pre-, and post-natal development studies with buprenorphine in rats
indicated increases in neonatal mortality after oral doses of 0.8 mg/kg/day and
up (approximately 0.5 times the human sublingual dose of 16 mg), after IM doses
of 0.5 mg/kg/day and up (approximately 0.3 times the human sublingual dose of
16 mg), and after SC doses of 0.1 mg/kg/day and up (approximately 0.06 times
the human sublingual dose of 16 mg). An apparent lack of milk production during
these studies likely contributed to the decreased pup viability and lactation
indices. Delays in the occurrence of righting reflex and startle response were
noted in rat pups at an oral dose of 80 mg/kg/day (approximately 50 times the
human sublingual dose of 16 mg).
Lactation
Risk Summary
Based on two studies in 13 lactating women maintained on
buprenorphine treatment, buprenorphine and its metabolite norbuprenorphine were
present in low levels in human milk and available data have not shown adverse
reactions in breastfed infants. There are no data on the combination product
buprenorphine/naloxone in breastfeeding, however oral absorption of naloxone is
limited. The developmental and health benefits of breastfeeding should be
considered along with the mother's clinical need for BUNAVAIL and any potential
adverse effects on the breastfed child from the drug or from the underlying
maternal condition.
Clinical Considerations
Advise the nursing mother taking BUNAVAIL to monitor the
infant for increased drowsiness and breathing difficulties.
Data
Data were consistent from two studies (N=13) of
breastfeeding infants whose mothers were maintained on sublingual doses of
buprenorphine ranging from 2.4 to 24 mg/day, showing that the infants were
exposed to less than 1% of the maternal daily dose.
In a study of six lactating women who were taking a
median sublingual buprenorphine dose of 0.29 mg/kg/day 5 to 8 days after
delivery, breast milk provided a median infant dose of 0.42 mcg/kg/day of
buprenorphine and 0.33 mcg/kg/day of norbuprenorphine, equal to 0.2% and 0.12%,
respectively, of the maternal weight-adjusted dose (relative dose/kg (%) of
norbuprenorphine was calculated from the assumption that buprenorphine and
norbuprenorphine are equipotent).
Data from a study of seven lactating women who were
taking a median sublingual buprenorphine dose of 7 mg/day an average of 1.12
months after delivery indicated that the mean milk concentrations (Cavg) of
buprenorphine and norbuprenorphine were 3.65 mcg/L and 1.94 mcg/L respectively.
Based on the study data, and assuming milk consumption of 150 mL/kg/day, an
exclusively breastfed infant would receive an estimated mean absolute infant
dose (AID) of 0.55 mcg/kg/day of buprenorphine and 0.29 mcg/kg/day of norbuprenorphine,
or a mean relative infant dose (RID) of 0.38% and 0.18%, respectively, of the
maternal weight-adjusted dose.
Females And Males Of Reproductive Potential
Infertility
Chronic use of opioids may cause reduced fertility in
females and males of reproductive potential. It is not known whether these
effects on fertility are reversible [see Nonclinical Toxicology].
Pediatric Use
The safety and effectiveness of BUNAVAIL have not been
established in pediatric patients.
This product is not appropriate for the treatment of
neonatal abstinence syndrome in neonates, because it contains naloxone, an
opioid antagonist.
Geriatric Use
Clinical studies of BUNAVAIL did not include sufficient
numbers of subjects aged 65 and over to determine whether they responded
differently than younger subjects. Other reported clinical experience has not
identified differences in responses between elderly and younger patients. Due
to possible decreased hepatic, renal, or cardiac function and of concomitant
disease or other drug therapy in geriatric patients, the decision to prescribe
BUNAVAIL should be made cautiously in individuals 65 years of age or older and
these patients should be monitored for signs and symptoms of toxicity or
overdose.
Hepatic Impairment
The effect of hepatic impairment on the pharmacokinetics
of buprenorphine and naloxone has been evaluated in a pharmacokinetic study.
Both drugs are extensively metabolized in the liver. While no clinically
significant changes have been observed in subjects with mild hepatic
impairment; the plasma levels have been shown to be higher and half-life values
have been shown to be longer for both buprenorphine and naloxone in subjects
with moderate and severe hepatic impairment. The magnitude of the effects on
naloxone is greater than that on buprenorphine in both moderately and severely
impaired subjects. The difference in magnitude of the effects on naloxone and
buprenorphine are greater in subjects with severe hepatic impairment than in
subjects with moderate hepatic impairment, and therefore the clinical impact of
these effects is likely to be greater in patients with severe hepatic
impairment than in patients with moderate hepatic impairment.
Buprenorphine/naloxone products should be avoided in patients with severe
hepatic impairment and may not be appropriate for patients with moderate
hepatic impairment [see WARNINGS AND PRECAUTIONS and CLINICAL
PHARMACOLOGY].
Renal Impairment
No differences in buprenorphine pharmacokinetics were
observed between 9 dialysis-dependent and 6 normal patients following IV
administration of 0.3 mg buprenorphine. The effects of renal failure on
naloxone pharmacokinetics are unknown.