Suboxone

Suboxone is a prescription medications used for the maintenance treatment of opioid dependence (addiction to opioid drugs). Suboxone should be used along with a complete treatment plan that includes counseling and psychosocial support. It contains 2 ingredients: buprenorphine and naloxone. Buprenorphine is in a group of drugs called opioid partial agonist-antagonists and naloxone is in a class of medications called opioid antagonists. These work by producing effects similar to opioid drugs and preventing withdrawal symptoms when someone stops taking opioid medications.

This medication is available as a film that is applied sublingually (under the tongue). Avoid eating or drinking until the film has dissolved entirely. Do not cut, chew, or swallow Suboxone films.

Common side effects of Suboxone include headache, nausea, excessive sweating, constipation, opioid withdrawal symptoms, insomnia, and pain.

Suboxone can also cause blurred vision, drowsiness, and dizziness. Do not drive or operate heavy machinery until you know how Suboxone affects you.

• Reckitt Benckiser Pharmaceuticals Inc.

Serious side effects have been reported with Suboxone. See the “Suboxone Precautions” section.

Common side effects of Suboxone include the following:

• Nausea
• Vomiting
• Drug withdrawal syndrome
• Headache
• Sweating
• Numb mouth
• Constipation
• Painful tongue
• The inside of your mouth is more red than normal
• Intoxication (feeling lightheaded or drunk)
• Disturbance in attention
• Irregular heart beat (palpitations)
• Decrease in sleep (insomnia)
• Blurred vision
• Back pain
• Fainting
• Dizziness
• Sleepiness

This is not a complete list of Suboxone side effects. Ask your doctor or pharmacist for more information.

Tell your doctor if you have any side effect that bothers you or that does not go away.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Before taking Suboxone, tell your doctor about all of your medical conditions. Especially tell your doctor if you:

• are allergic to buprenorphine and naloxone or to any of its ingredients
• have or have had adrenal problems such as Addison's disease
• have or have had benign prostatic hypertrophy (BPH, enlargement of the prostate gland)
• have or have had difficulty urinating
• have or have had a head injury
• have or have had hallucinations (seeing things or hearing voices that do not exist)
• have a curve in the spine that makes it hard to breathe
• have or have had gallbladder disease
• have or have had stomach conditions
• have or have had thyroid disease
• have or have had kidney disease
• have or have had liver disease
• have trouble breathing or lung problems
• have a history of alcoholism
• drink large amounts of alcohol
• are pregnant or breastfeeding

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements.

Buprenorphine and naloxone sublingual tablet is used to treat opioid (narcotic) dependence or addiction. Buprenorphine and naloxone buccal film, sublingual film, or sublingual tablet is used for induction and maintenance treatment of opioid (narcotic) dependence. It should be used in patients who have already been treated with buprenorphine sublingual tablets.

When a narcotic medicine is used for a long time, it may become habit-forming, causing mental or physical dependence. Physical dependence may lead to withdrawal side effects if the narcotic is stopped suddenly. Severe withdrawal side effects can usually be prevented when a person is switched to buprenorphine and naloxone combination. It acts on the central nervous system (CNS) to help prevent the withdrawal side effects.

This medicine is available only with your doctor's prescription.

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies have not been performed on the relationship of age to the effects of buprenorphine and naloxone buccal film, sublingual film, or sublingual tablet in the pediatric population. Safety and efficacy have not been established.

Geriatric

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of buprenorphine and naloxone combination in the elderly. However, elderly patients are more likely to have age-related kidney, liver, or heart problems, which may require caution and an adjustment in the dose for patients receiving buprenorphine and naloxone combination.

Pregnancy

Breast Feeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Interactions with Medicines

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

• Nalmefene
• Naltrexone
• Safinamide

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Acepromazine
• Alfentanil
• Almotriptan
• Alprazolam
• Amineptine
• Amisulpride
• Amitriptyline
• Amitriptylinoxide
• Amobarbital
• Amoxapine
• Amphetamine
• Aripiprazole
• Asenapine
• Atazanavir
• Baclofen
• Benperidol
• Benzphetamine
• Bromazepam
• Bromopride
• Brompheniramine
• Buspirone
• Butabarbital
• Butorphanol
• Carbamazepine
• Carbinoxamine
• Carisoprodol
• Carphenazine
• Chloral Hydrate
• Chlordiazepoxide
• Chlorpheniramine
• Chlorpromazine
• Chlorzoxazone
• Citalopram
• Clobazam
• Clomipramine
• Clonazepam
• Clorazepate
• Clozapine
• Cocaine
• Codeine
• Cyclobenzaprine
• Desipramine
• Desmopressin
• Desvenlafaxine
• Dexmedetomidine
• Dextroamphetamine
• Dextromethorphan
• Dezocine
• Diazepam
• Dibenzepin
• Dichloralphenazone
• Difenoxin
• Diphenhydramine
• Diphenoxylate
• Dolasetron
• Donepezil
• Doxepin
• Doxylamine
• Droperidol
• Duloxetine
• Eletriptan
• Enflurane
• Escitalopram
• Estazolam
• Eszopiclone
• Ethchlorvynol
• Ethopropazine
• Ethylmorphine
• Fentanyl
• Flibanserin
• Fluoxetine
• Fluphenazine
• Flurazepam
• Fluspirilene
• Fluvoxamine
• Fospropofol
• Frovatriptan
• Furazolidone
• Granisetron
• Halazepam
• Haloperidol
• Halothane
• Hexobarbital
• Hydrocodone
• Hydromorphone
• Hydroxytryptophan
• Hydroxyzine
• Imipramine
• Iproniazid
• Isocarboxazid
• Isoflurane
• Ketamine
• Ketazolam
• Ketobemidone
• Levomilnacipran
• Levorphanol
• Linezolid
• Lisdexamfetamine
• Lithium
• Lofepramine
• Lorazepam
• Lorcaserin
• Loxapine
• Meclizine
• Melitracen
• Melperone
• Meperidine
• Mephobarbital
• Meprobamate
• Meptazinol
• Mesoridazine
• Metaxalone
• Methadone
• Methamphetamine
• Methdilazine
• Methocarbamol
• Methohexital
• Methotrimeprazine
• Methylene Blue
• Midazolam
• Milnacipran
• Mirtazapine
• Moclobemide
• Molindone
• Moricizine
• Morphine
• Morphine Sulfate Liposome
• Nalbuphine
• Naldemedine
• Naloxegol
• Naratriptan
• Nefazodone
• Nialamide
• Nicomorphine
• Nitrazepam
• Nitrous Oxide
• Nortriptyline
• Olanzapine
• Ondansetron
• Opipramol
• Opium
• Opium Alkaloids
• Orphenadrine
• Oxazepam
• Oxycodone
• Oxymorphone
• Palonosetron
• Papaveretum
• Paregoric
• Paroxetine
• Pentazocine
• Pentobarbital
• Perampanel
• Perazine
• Periciazine
• Perphenazine
• Phenelzine
• Phenobarbital
• Pimozide
• Piperacetazine
• Pipotiazine
• Piritramide
• Prazepam
• Primidone
• Procarbazine
• Prochlorperazine
• Promazine
• Promethazine
• Propofol
• Protriptyline
• Quazepam
• Quetiapine
• Ramelteon
• Rasagiline
• Remifentanil
• Remoxipride
• Rizatriptan
• Secobarbital
• Selegiline
• Sertindole
• Sertraline
• Sibutramine
• Sodium Oxybate
• St John's Wort
• Sufentanil
• Sulpiride
• Sumatriptan
• Suvorexant
• Tapentadol
• Temazepam
• Thiethylperazine
• Thiopental
• Thiopropazate
• Thioridazine
• Tianeptine
• Tilidine
• Tizanidine
• Tolonium Chloride
• Topiramate
• Tramadol
• Tranylcypromine
• Trazodone
• Triazolam
• Trifluoperazine
• Trifluperidol
• Triflupromazine
• Trimeprazine
• Trimipramine
• Tryptophan
• Venlafaxine
• Vilazodone
• Vortioxetine
• Zaleplon
• Ziprasidone
• Zolpidem
• Zopiclone
• Zotepine

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Clonidine
• Yohimbine

Interactions with Food/Tobacco/Alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following is usually not recommended, but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco.

• Ethanol

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

• Addison disease (adrenal gland problem) or
• Alcohol abuse, or history of or
• Asthma, severe or
• Brain tumor, history of or
• Breathing problems, severe (eg, hypoxia, hypercapnia) or
• Chronic obstructive pulmonary disease (COPD) or
• CNS depression or
• Cor pulmonale (serious heart condition) or
• Drug dependence, especially with narcotics, or history of or
• Enlarged prostate (BPH, prostatic hypertrophy) or
• Gallbladder disease or gallstones or
• Head injuries, history of or
• Heart disease or
• Hepatitis B or C, history of or
• Hypothyroidism (an underactive thyroid) or
• Hypovolemia (low blood volume) or
• Kyphoscoliosis (curvature of the spine with breathing problems) or
• Mental health problems, history of or
• Problems with passing urine or
• Stomach problems—Use with caution. May increase risk for more serious side effects.

• Hypotension (low blood pressure)—Use with caution. May make this condition worse.

• Liver disease, moderate—Use with caution. The effects may be increased because of slower removal of the medicine from the body.

• Liver disease, severe—Should not be used in patients with this condition.

Pregnancy

Risk Summary

There are no adequate and well-controlled studies of Suboxone sublingual film or buprenorphine/naloxone in pregnant women. Limited published data on use of buprenorphine, the active ingredient in Suboxone sublingual film, in pregnancy, have not shown an increased risk of major malformations. All pregnancies, regardless of drug exposure, have a background risk of 2% to 4% for major birth defects, and 15% to 20% for pregnancy loss. Reproductive and developmental studies in rats and rabbits identified adverse events at clinically relevant doses. Pre- and postnatal development studies in rats demonstrated dystocia, increased neonatal deaths, and developmental delays. No clear teratogenic effects were seen with a range of doses equivalent to or greater than the human dose. However, in a few studies, some events such as acephalus, omphalocele, and skeletal abnormalities were observed but these findings were not clearly treatment-related. Embryofetal death was also observed in both rats and rabbits.

Suboxone sublingual film should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

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.

Fetal/neonatal adverse reactions

Neonatal opioid withdrawal syndrome may occur in newborn infants of mothers who are receiving treatment with Suboxone.

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 after 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 (5.5)].

Labor or Delivery

As with all opioids, use of buprenorphine prior to delivery may result in respiratory depression in the newborn. Closely monitor neonates for signs of respiratory depression. An opioid antagonist such as naloxone should be available for reversal of opioid induced respiratory depression in the neonate.

Data

Human Data

Studies have been conducted to evaluate neonatal outcomes in women exposed to buprenorphine during pregnancy. Limited published data on malformations from trials, observational studies, case series, and case reports on buprenorphine use in pregnancy have not shown an increased risk of major malformations. Based on these studies the incidence of neonatal abstinence syndrome is not clear and there does not appear to be a dose-response relationship.

Animal Data

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. Following oral administration to rats and rabbits, no teratogenic effects were observed at buprenorphine doses up to 250 mg/kg/day and 40 mg/kg/day, respectively (estimated exposure approximately 150 times and 50 times, respectively, the recommended human daily sublingual dose of 16 mg on a mg/m² basis). 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 recommended human daily dose of 16 mg on a mg/m² basis). 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. 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 recommended human daily sublingual dose of 16 mg on a mg/m² basis). 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 recommended human daily sublingual dose of 16 mg on a mg/m2 basis), after IV doses up to 0.8 mg/kg/day (estimated exposure was approximately 0.5 times and equal to, respectively, the recommended human daily sublingual dose of 16 mg on a mg/m2 basis), or after oral doses up to 160 mg/kg/day in rats (estimated exposure was approximately 95 times the recommended human daily sublingual dose of 16 mg on a mg/m2 basis) and 25 mg/kg/day in rabbits (estimated exposure was approximately 30 times the recommended human daily sublingual dose of 16 mg on a mg/m2 basis). 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 recommended human daily sublingual dose of 16 mg on a mg/m2 basis), 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 recommended human daily sublingual dose of 16 mg on a mg/m2 basis) or oral administration of 1 mg/kg/day or greater (estimated exposure was approximately equal to the recommended human daily sublingual dose of 16 mg on a mg/m2 basis) 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 recommended human daily sublingual dose of 16 mg on a mg/m2 basis).

Dystocia was noted in pregnant rats treated intramuscularly with buprenorphine 5 mg/kg/day (approximately 3 times the recommended human daily sublingual dose of 16 mg on a mg/m² basis). Fertility, peri-, 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 recommended human daily sublingual dose of 16 mg on a mg/m² basis), after IM doses of 0.5 mg/kg/day and up (approximately 0.3 times the recommended human daily sublingual dose of 16 mg on a mg/m² basis), and after SC doses of 0.1 mg/kg/day and up (approximately 0.06 times the recommended human daily sublingual dose of 16 mg on a mg/m² basis). 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 recommended human daily sublingual dose of 16 mg on a mg/m² basis).

Nursing Mothers

Risk Summary

Based on two studies in 13 lactating women, buprenorphine and its metabolite norbuprenorphine are present in low levels in human milk and infant urine, 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 minimal. Caution should be exercised when Suboxone sublingual film is administered to a nursing woman. The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for Suboxone sublingual film 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 Suboxone sublingual film to monitor the infant for increased drowsiness and breathing difficulties.

Data

Based on limited data from a study of 6 lactating women who were taking a median oral dose of buprenorphine of 0.29 mg/kg/day 5 to 8 days after delivery, breast milk contained a median infant dose of 0.42 mcg/kg/day of buprenorphine and 0.33 mcg/kg/day of norbuprenorphine, which are equal to 0.2% and 0.12% of the maternal weight-adjusted dose.

Based on limited data from a study of 7 lactating women who were taking a median oral dose of buprenorphine of 7 mg/day an average of 1.12 months after delivery, the mean milk concentrations of buprenorphine and norbuprenorphine were 3.65 mcg/L and 1.94 mcg/L respectively. Based on the limited data from this study, and assuming milk consumption of 150 mL/kg/day, an exclusively breastfed infant would receive an estimated mean of 0.55 mcg/kg/day of buprenorphine and 0.29 mcg/kg/day of norbuprenorphine, which are 0.38% and 0.18% of the maternal weight-adjusted dose.

No adverse reactions were observed in the infants in these two studies.

Pediatric Use

The safety and effectiveness of Suboxone sublingual film 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 Suboxone sublingual film, Suboxone (buprenorphine and naloxone) sublingual tablets, or SUBUTEX (buprenorphine) sublingual tablets 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 the elderly and younger patients. 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.

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 are 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 (5.11) and Clinical Pharmacology (12.3)].

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.

Mechanism of Action

Suboxone sublingual film contains buprenorphine and naloxone. Buprenorphine is a partial agonist at the mu-opioid receptor and an antagonist at the kappa-opioid receptor. Naloxone is a potent antagonist at mu-opioid receptors and produces opioid withdrawal signs and symptoms in individuals physically dependent on full opioid agonists when administered parenterally.

Pharmacodynamics

Subjective Effects

Comparisons of buprenorphine to full opioid agonists such as methadone and hydromorphone suggest that sublingual buprenorphine produces typical opioid agonist effects which are limited by a ceiling effect.

In opioid-experienced subjects who were not physically dependent, acute sublingual doses of buprenorphine/naloxone tablets produced opioid agonist effects which reached a maximum between doses of 8 mg/2 mg and 16 mg/4 mg buprenorphine/naloxone.

Opioid agonist ceiling-effects were also observed in a double-blind, parallel group, dose-ranging comparison of single doses of buprenorphine sublingual solution (1, 2, 4, 8, 16, or 32 mg), placebo and a full agonist control at various doses. The treatments were given in ascending dose order at intervals of at least one week to 16 opioid-experienced subjects who were not physically dependent. Both active drugs produced typical opioid agonist effects. For all measures for which the drugs produced an effect, buprenorphine produced a dose-related response. However, in each case, there was a dose that produced no further effect. In contrast, the highest dose of the full agonist control always produced the greatest effects. Agonist objective rating scores remained elevated for the higher doses of buprenorphine (8 mg to 32 mg) longer than for the lower doses and did not return to baseline until 48 hours after drug administration. The onset of effects appeared more rapidly with buprenorphine than with the full agonist control, with most doses nearing peak effect after 100 minutes for buprenorphine compared to 150 minutes for the full agonist control.

Physiologic Effects

Buprenorphine in IV (2, 4, 8, 12 and 16 mg) and sublingual (12 mg) doses has been administered to opioid-experienced subjects who were not physically dependent to examine cardiovascular, respiratory, and subjective effects at doses comparable to those used for treatment of opioid dependence. Compared to placebo, there were no statistically significant differences among any of the treatment conditions for blood pressure, heart rate, respiratory rate, O2 saturation, or skin temperature across time. Systolic BP was higher in the 8 mg group than placebo (3 hour AUC values). Minimum and maximum effects were similar across all treatments. Subjects remained responsive to low voice and responded to computer prompts. Some subjects showed irritability, but no other changes were observed.

The respiratory effects of sublingual buprenorphine were compared with the effects of methadone in a double-blind, parallel group, dose ranging comparison of single doses of buprenorphine sublingual solution (1, 2, 4, 8, 16, or 32 mg) and oral methadone (15, 30, 45, or 60 mg) in non-dependent, opioid-experienced volunteers. In this study, hypoventilation not requiring medical intervention was reported more frequently after buprenorphine doses of 4 mg and higher than after methadone. Both drugs decreased O2 saturation to the same degree.

Effect of Naloxone

Physiologic and subjective effects following acute sublingual administration of buprenorphine tablets and buprenorphine/naloxone tablets were similar at equivalent dose levels of buprenorphine. Naloxone had no clinically significant effect when administered by the sublingual route, although blood levels of the drug were measurable. Buprenorphine/naloxone, when administered sublingually to an opioid-dependent cohort, was recognized as an opioid agonist, whereas when administered intramuscularly, combinations of buprenorphine with naloxone produced opioid antagonist actions similar to naloxone. This finding suggests that the naloxone in buprenorphine/naloxone tablets may deter injection of buprenorphine/naloxone tablets by persons with active substantial heroin or other full mu-opioid dependence. However, clinicians should be aware that some opioid-dependent persons, particularly those with a low level of full mu-opioid physical dependence or those whose opioid physical dependence is predominantly to buprenorphine, abuse buprenorphine/naloxone combinations by the intravenous or intranasal route. In methadone-maintained patients and heroin-dependent subjects, IV administration of buprenorphine/naloxone combinations precipitated opioid withdrawal signs and symptoms and was perceived as unpleasant and dysphoric. In morphine-stabilized subjects, intravenously administered combinations of buprenorphine with naloxone produced opioid antagonist and withdrawal signs and symptoms that were ratio-dependent; the most intense withdrawal signs and symptoms were produced by 2:1 and 4:1 ratios, less intense by an 8:1 ratio.

Pharmacokinetics

Absorption

In several pharmacokinetic studies following the administration of different dosages, a dose of one or two of the 2 mg/0.5 mg Suboxone sublingual films administered sublingually or buccally showed comparable relative bioavailability to the same total dose of Suboxone sublingual tablets. In contrast, one 8 mg/2 mg and one 12 mg/3 mg Suboxone sublingual films administered sublingually or buccally showed higher relative bioavailability for both buprenorphine and naloxone compared to the same total dose of Suboxone sublingual tablets. A combination of one 8 mg/2 mg and two 2 mg/0.5 mg Suboxone sublingual films (total dose of 12 mg/ 3 mg) administered sublingually showed comparable relative bioavailability to the same total dose of Suboxone sublingual tablets, while buccally administered Suboxone sublingual films showed higher relative bioavailability. Table 4, below, illustrates the relative increase in exposure to buprenorphine and naloxone associated with Suboxone sublingual films compared to Suboxone tablets, and shows the effect of route of administration [see Dosage and Administration (2.8 and 2.9)].

Across relevant pharmacokinetic studies, the pharmacokinetic parameters and exposures derived from the buccal and sublingual administrations of Suboxone sublingual film were comparable to one another.

Distribution

Buprenorphine is approximately 96% protein bound, primarily to alpha and beta globulin.

Naloxone is approximately 45% protein bound, primarily to albumin.

Elimination

Buprenorphine is metabolized and eliminated in urine and feces. Naloxone undergoes metabolism as well. When Suboxone sublingual film is administered sublingually or buccally, buprenorphine has a mean elimination half-life ranging from 24 to 42 hours and naloxone has a mean elimination half-life ranging from 2 to 12 hours.

Metabolism

Buprenorphine undergoes both N-dealkylation to norbuprenorphine and glucuronidation. The N-dealkylation pathway is mediated primarily by the CYP3A4. Norbuprenorphine, the major metabolite, can further undergo glucuronidation. Norbuprenorphine has been found to bind opioid receptors in vitro; however, it has not been studied clinically for opioid-like activity. Naloxone undergoes direct glucuronidation to naloxone-3-glucuronide as well as N-dealkylation, and reduction of the 6-oxo group.

Excretion

A mass balance study of buprenorphine showed complete recovery of radiolabel in urine (30%) and feces (69%) collected up to 11 days after dosing. Almost all of the dose was accounted for in terms of buprenorphine, norbuprenorphine, and two unidentified buprenorphine metabolites. In urine, most of buprenorphine and norbuprenorphine was conjugated (buprenorphine, 1% free and 9.4% conjugated; norbuprenorphine, 2.7% free and 11% conjugated). In feces, almost all of the buprenorphine and norbuprenorphine were free (buprenorphine, 33% free and 5% conjugated; norbuprenorphine, 21% free and 2% conjugated). Based on all studies performed with sublingually and buccally administered Suboxone sublingual film, buprenorphine has a mean elimination half-life from plasma ranging from 24 to 42 hours and naloxone has a mean elimination half-life from plasma ranging from 2 to 12 hours.

Drug-drug Interactions

CYP3A4 Inhibitors and Inducers: Subjects receiving Suboxone sublingual film should be monitored if inhibitors of CYP3A4 such as azole antifungal agents (e.g., ketoconazole), macrolide antibiotics (e.g., erythromycin) or HIV protease inhibitors and may require dose-reduction of one or both agents. The interaction of buprenorphine with all CYP3A4 inducers has not been studied, therefore it is recommended that patients receiving Suboxone sublingual film be monitored for signs and symptoms of opioid withdrawal if inducers of CYP3A4 (e.g., phenobarbital, carbamazepine, phenytoin, rifampicin) are coadministered [see Drug Interactions (7.1)].

Buprenorphine has been found to be a CYP2D6 and CYP3A4 inhibitor and its major metabolite, norbuprenorphine, has been found to be a moderate CYP2D6 inhibitor in in vitro studies employing human liver microsomes. However, the relatively low plasma concentrations of buprenorphine and norbuprenorphine resulting from therapeutic doses are not expected to raise significant drug-drug interaction concerns.

Special Populations:

Hepatic Impairment: In a pharmacokinetic study, the disposition of buprenorphine and naloxone were determined after administering a Suboxone 2.0/0.5 mg (Buprenorphine/Naloxone) sublingual tablet in subjects with varied degrees of hepatic impairment as indicated by Child-Pugh criteria. The disposition of buprenorphine and naloxone in patients with hepatic impairment were compared to disposition in subjects with normal hepatic function.

In subjects with mild hepatic impairment, the changes in mean Cmax, AUC0-last, and half-life values of both buprenorphine and naloxone were not clinically significant. No dosing adjustment is needed in patients with mild hepatic impairment.

For subjects with moderate and severe hepatic impairment, mean Cmax, AUC0-last, and half-life values of both buprenorphine and naloxone were increased; the effects on naloxone are greater than that on buprenorphine (Table 5).

The difference in magnitude of the effects on naloxone and buprenorphine are greater in subjects with severe hepatic impairment than 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 (5.11) and Use in Specific Populations (8.6)].

HCV infection: In subjects with HCV infection but no sign of hepatic impairment, the changes in the mean Cmax, AUC0-last, and half-life values of buprenorphine and naloxone were not clinically significant in comparison to healthy subjects without HCV infection. No dosing adjustment is needed in patients with HCV infection.

• other narcotic medications - opioid pain medicine or prescription cough medicine;

• drugs that make you sleepy or slow your breathing - a sleeping pill, muscle relaxer, sedative, tranquilizer, or antipsychotic medicine; or

• drugs that affect serotonin levels in your body - medicine for depression, Parkinson's disease, migraine headaches, serious infections, or prevention of nausea and vomiting.

This list is not complete and many other drugs can interact with buprenorphine and naloxone. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide. Tell your doctor about all medicines you use, and those you start or stop using. Give a list of all your medicines to any healthcare provider who treats you.

• Quickly absorbed via the sublingual route. Maximum concentrations reached within two hours.
• There may be a difference in effectiveness between Suboxone sublingual tablets and Suboxone sublingual film. Those switching may need to be monitored for over or under-medication.

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