Buprenorphine and Naloxone

INDICATIONS AND USAGE Buprenorphine and naloxone sublingual tablets are indicated for the maintenance treatment of opioid dependence. Buprenorphine and naloxone sublingual tablets should be used as part of a complete treatment plan that includes counseling and psychosocial support. Buprenorphine and naloxone sublingual tablets contain buprenorphine, a partial opioid agonist, and naloxone, an opioid antagonist, and are indicated for the maintenance treatment of opioid dependence. ( 1 ) Buprenorphine and naloxone sublingual tablets should be used as part of a complete treatment plan that includes counseling and psychosocial support. ( 1 )

DOSAGE AND ADMINISTRATION Administer buprenorphine and naloxone sublingual tablet sublingually as a single daily dose. ( 2.1 ) Strongly consider recommending or prescribing an opioid overdose reversal agent (e.g., naloxone, nalmefene) at the time buprenorphine and naloxone sublingual tablet are initiated or renewed because patients being treated for opioid use disorder have the potential for relapse, putting them at risk for opioid overdose. ( 2.2 ) To avoid precipitating withdrawal, induction with buprenorphine sublingual tablets should be undertaken when objective and clear signs of withdrawal are evident. After induction, doses of buprenorphine and naloxone sublingual tablets should be progressively adjusted to a level that holds the patient in treatment and suppresses opioid withdrawal signs and symptoms ( 2.3 ) The maintenance dose of buprenorphine and naloxone sublingual tablets is generally in the range of 4 mg/1 mg to 24 mg/6 mg per day and should be based on clinical response. ( 2.3 ) Administer buprenorphine and naloxone sublingual tablets as directed in the Full Prescribing Information. ( 2.3 , 2.4 ) When discontinuing treatment, gradually taper to avoid signs and symptoms of withdrawal. ( 2.7 ) 2.1 Important Dosage and Administration Information Buprenorphine and naloxone sublingual tablet is administered sublingually as a single daily dose. Buprenorphine and naloxone sublingual tablets should be used in patients who have been initially inducted using buprenorphine sublingual tablets. Medication should be prescribed in consideration of the frequency of visits. Provision of multiple refills is not advised early in treatment or without appropriate patient follow-up visits. 2.2 Patient Access to an Opioid Overdose Reversal Agent for the Emergency Treatment of Opioid Overdose Inform patients and caregivers about opioid overdose reversal agents (e.g., naloxone, nalmefene) and discuss the importance of having access to an opioid overdose reversal agent. Because patients being treated for opioid use disorder have the potential for relapse, putting them at risk for opioid overdose, strongly consider recommending or prescribing an overdose reversal agent for the emergency treatment of opioid overdose, both when initiating and renewing treatment with buprenorphine and naloxone sublingual tablets. Also consider recommending or prescribing such an agent if the patient has household members (including children) or other close contacts at risk for accidental ingestion or opioid overdose [see Warnings and Precautions (5.2) ]. Discuss the options for obtaining an opioid overdose reversal agent (e.g., prescription, over-the-counter, or as part of a community-based program) [see Warnings and Precautions (5.2) ] . There are important differences among the opioid overdose reversal agents, such as route of administration, product strength, approved patient age range, and pharmacokinetics. Be familiar with these differences, as outlined in the approved labeling for those products, prior to recommending or prescribing such an agent. Advise patients and caregivers that opioid overdose reversal agents, such as naloxone or nalmefene, may also be administered for a known or suspected overdose with buprenorphine and naloxone sublingual tablets itself. Higher than normal doses and repeated administration of an opioid overdose reversal agent may be necessary due to the long duration of action of buprenorphine and naloxone sublingual tablets and its affinity for the mu‐opioid receptor [see Overdosage (10) ]. 2.3 Maintenance The dosage of buprenorphine and naloxone sublingual tablet should be progressively adjusted in increments/decrements of 2 mg/0.5 mg or 4 mg/1 mg buprenorphine/naloxone to a level that holds the patient in treatment and suppresses opioid withdrawal signs and symptoms. After treatment induction to the recommended dose of 16 mg/4 mg buprenorphine/naloxone, dosing should be further adjusted based on the individual patient and clinical response. The maintenance dose of buprenorphine and naloxone sublingual tablets is generally in the range of 4 mg/1 mg buprenorphine/naloxone to 24 mg/6 mg buprenorphine/naloxone per day. Dosages higher than 24 mg/6 mg daily have not been investigated in randomized clinical trials but may be appropriate for some patients. When determining the prescription quantity for unsupervised administration, consider the patient's level of stability, the security of his or her home situation, and other factors likely to affect the ability to manage supplies of take-home medication. There is no maximum recommended duration of maintenance treatment. Patients may require treatment indefinitely and should continue for as long as patients are benefiting and the use of buprenorphine and naloxone sublingual tablets contributes to the intended treatment goals. 2.4 Method of Administration Buprenorphine and naloxone sublingual tablets must be administered whole. Do not cut, chew, or swallow buprenorphine and naloxone sublingual tablets. Advise patients not to eat or drink anything until the tablet is completely dissolved. Buprenorphine and naloxone sublingual tablet should be placed under the tongue until it is dissolved. For doses requiring the use of more than two tablets, patients are advised to either place all the tablets at once or alternatively (if they cannot fit in more than two tablets comfortably), place two tablets at a time under the tongue. Either way, the patients should continue to hold the tablets under the tongue until they dissolve; swallowing the tablets reduces the bioavailability of the drug. To ensure consistency in bioavailability, patients should follow the same manner of dosing with continued use of the product. Proper administration technique should be demonstrated to the patient. Advise patients to do the following after the product has completely dissolved in the oral mucosa: take a sip of water, swish gently around the teeth and gums, and swallow. Advise patients to wait for at least one hour after taking buprenorphine and naloxone sublingual tablets before brushing teeth [see Warnings and Precautions (5.13) , Postmarketing Experience (6.2) , Information for Patients (17) , and the Medication Guide ]. 2.5 Clinical Supervision Treatment should be initiated with supervised administration, progressing to unsupervised administration as the patient's clinical stability permits. Buprenorphine and naloxone sublingual tablets are subject to diversion and abuse. When determining the prescription quantity for unsupervised administration, consider the patient's level of stability, the security of his or her home situation, and other factors likely to affect the ability to manage supplies of take-home medication. Ideally patients should be seen at reasonable intervals (e.g., at least weekly during the first month of treatment) based upon the individual circumstances of the patient. Medication should be prescribed in consideration of the frequency of visits. Provision of multiple refills is not advised early in treatment or without appropriate patient follow-up visits. Periodic assessment is necessary to determine compliance with the dosing regimen, effectiveness of the treatment plan, and overall patient progress. Once a stable dosage has been achieved and patient assessment (e.g., urine drug screening) does not indicate illicit drug use, less frequent follow-up visits may be appropriate. A once-monthly visit schedule may be reasonable for patients on a stable dosage of medication who are making progress toward their treatment objectives. Continuation or modification of pharmacotherapy should be based on the healthcare provider's evaluation of treatment outcomes and objectives such as: Absence of medication toxicity Absence of medical or behavioral adverse effects Responsible handling of medications by the patient Patient's compliance with all elements of the treatment plan (including recovery-oriented activities, psychothe

WARNINGS AND PRECAUTIONS Addiction, Abuse, and Misuse: Buprenorphine can be abused in a similar manner to other opioids. Clinical monitoring appropriate to the patient's level of stability is essential. Monitor patients for conditions indicative of diversion or progression of opioid dependence and addictive behaviors. Multiple refills should not be prescribed early in treatment or without appropriate patient follow-up visits. ( 5.1 ) Respiratory Depression: Life-threatening respiratory depression and death have occurred in association with buprenorphine use. Warn patients of the potential danger of self-administration of benzodiazepine or other CNS depressants while under treatment with buprenorphine and naloxone sublingual tablets. ( 5.2 , 5.3 ). Unintentional Pediatric Exposure: Store buprenorphine and naloxone sublingual tablets safely out of the sight and reach of children. Buprenorphine can cause severe, possibly fatal, respiratory depression in children. ( 5.4 ) Neonatal Opioid Withdrawal Syndrome: Neonatal opioid withdrawal syndrome (NOWS) is an expected and treatable outcome of prolonged use of opioids during pregnancy. ( 5.5 ) Adrenal Insufficiency: If diagnosed, treat with physiologic replacement of corticosteroids, and wean patient off of the opioid. ( 5.6 ) Risk of Opioid Withdrawal with Abrupt Discontinuation: If treatment is temporarily interrupted or discontinued, monitor patients for withdrawal and treat appropriately. ( 5.7 ) Risk of Hepatitis, Hepatic Events: Monitor liver function tests prior to initiation and during treatment and evaluate suspected hepatic events. ( 5.8 ) Precipitation of Opioid Withdrawal Signs and Symptoms: An opioid withdrawal syndrome is likely to occur with parenteral misuse of buprenorphine and naloxone sublingual tablets by individuals physically dependent on full opioid agonists, or by sublingual administration before the agonist effects of other opioids have subsided. ( 5.10 ) Risk of Overdose in Opioid-Naïve Patients: Buprenorphine and naloxone sublingual tablet is not appropriate as an analgesic. There have been reported deaths of opioid naïve individuals who received a 2 mg sublingual dose. ( 5.11 ) 5.1 Addiction, Abuse, and Misuse Buprenorphine and naloxone sublingual tablets contain 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 (9.2) ] . 5.2 Life-Threatening Respiratory Depression 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 depressant, including alcohol. Warn patients of the potential danger of self-administration of benzodiazepines or other CNS depressants while under treatment with buprenorphine and naloxone sublingual tablets [see Warnings and Precautions (5.3) , Drug Interactions (7) ] . Use buprenorphine and naloxone sublingual tablets 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). Educate patients and caregivers on how to recognize respiratory depression and emphasize the importance of calling 911 or getting emergency medical help right away in the event of a known or suspected overdose [see Patient Counseling Information (17) ]. Opioids can cause sleep-related breathing disorders including central sleep apnea (CSA) and sleep-related hypoxemia. Opioid use increases the risk of CSA in a dose-dependent fashion. In patients who present with CSA, consider decreasing the opioid dosage using best practices for opioid taper [see Dosage and Administration (2.7) ]. Patient Access to an Opioid Overdose Reversal Agent for the Emergency Treatment of Opioid Overdose Inform patients and caregivers about opioid overdose reversal agents (e.g., naloxone, nalmefene) and discuss the importance of having access to an opioid overdose reversal agent. Because patients being treated for opioid use disorder have the potential for relapse, putting them at risk for opioid overdose, strongly consider recommending or prescribing an opioid overdose reversal agent for the emergency treatment of an opioid overdose, both when initiating and renewing treatment with buprenorphine and naloxone sublingual tablets. Also consider recommending or prescribing such an agent if the patient has household members (including children) or other close contacts at risk for accidental ingestion or opioid overdose [see Dosage and Administration (2.2) ]. Discuss the options for obtaining an opioid overdose reversal agent (e.g., prescription, over-the-counter, or as part of a community-based program). There are important differences among the opioid overdose reversal agents, such as route of administration, product strength, approved patient age range, and pharmacokinetics. Be familiar with these differences, as outlined in the approved labeling for those products, prior to recommending or prescribing such an agent. Advise patients and caregivers that an opioid overdose reversal agent, such as naloxone or nalmefene, may also be administered for a known or suspected overdose with buprenorphine and naloxone sublingual tablets itself. Higher than normal doses and repeated administration of an opioid overdose reversal agent may be necessary due to the long duration of action of buprenorphine and naloxone sublingual tablets and its affinity for the mu‐opioid receptor [see Overdosage (10) ] . Educate patients and caregivers on how to recognize respiratory depression, and how to use an opioid overdose reversal agent for the emergency treatment of opioid overdose. Emphasize the importance of calling 911 or getting emergency medical help, even if an opioid overdose reversal agent is administered. 5.3 Risks from Concomitant Use with Benzodiazepines or Other CNS Depressants Concomitant use of buprenorphine and benzodiazepines and/or other CNS depressants (e.g., alcohol, non-benzodiazepine sedative/hypnotics, anxiolytics, tranquilizers, muscle relaxants, general anesthetics, antipsychotics, gabapentinoids [gabapentin or pregabalin], and other opioids) increases the risk of adverse reactions including overdose, respiratory depression, 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

CONTRAINDICATIONS Buprenorphine and naloxone sublingual tablets are contraindicated in patients with a history of hypersensitivity to buprenorphine or naloxone as serious adverse reactions, including anaphylactic shock, have been reported [ see Warnings and Precautions ( 5.9 )] . Hypersensitivity to buprenorphine or naloxone. ( 4 )

DRUG INTERACTIONS Table 3 Includes clinically significant drug interactions with buprenorphine and naloxone sublingual tablets. Table 3. Clinically Significant Drug Interactions with Buprenorphine and Naloxone Sublingual Tablets Benzodiazepines or other Central Nervous System (CNS) Depressants Clinical Impact: Due to additive pharmacologic effects, the concomitant use of benzodiazepines or other CNS depressants, including alcohol, can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death. Intervention: 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. Before co-prescribing benzodiazepines for anxiety or insomnia, ensure that patients are appropriately diagnosed and consider alternative medications and non-pharmacologic treatments [see Warnings and Precautions (5.2 , 5.3) ] . If concomitant use is warranted, strongly consider recommending or prescribing an opioid overdose reversal agent, as is recommended for all patients on buprenorphine and naloxone treatment for opioid use disorder [see Warnings and Precautions (5.2) ]. Examples Benzodiazepines and other sedatives/hypnotics, anxiolytics, tranquilizers, muscle relaxants, general anesthetics, antipsychotics, gabapentinoids (gabapentin or pregabalin), other opioids, and alcohol. Inhibitors of CYP3A4 Clinical Impact: The concomitant use of buprenorphine and CYP3A4 inhibitors can increase the plasma concentration of buprenorphine, resulting in increased or prolonged opioid effects, particularly when an inhibitor is added after a stable dose of buprenorphine and naloxone sublingual tablet is achieved. After stopping a CYP3A4 inhibitor, as the effects of the inhibitor decline, the buprenorphine plasma concentration will decrease [see Clinical Pharmacology (12.3) ] , potentially resulting in decreased opioid efficacy or a withdrawal syndrome in patients who had developed physical dependence to buprenorphine. Intervention: If concomitant use is necessary, consider dosage reduction of buprenorphine and naloxone sublingual tablets until stable drug effects are achieved. Monitor patients for respiratory depression and sedation at frequent intervals. If a CYP3A4 inhibitor is discontinued, consider increasing the buprenorphine and naloxone sublingual tablets dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal. Examples: Macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g. ketoconazole), protease inhibitors (e.g., ritonavir) CYP3A4 Inducers Clinical Impact: The concomitant use of buprenorphine and CYP3A4 inducers can decrease the plasma concentration of buprenorphine [see Clinical Pharmacology (12.3) ] , potentially resulting in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence to buprenorphine. After stopping a CYP3A4 inducer, as the effects of the inducer decline, the buprenorphine plasma concentration will increase [see Clinical Pharmacology (12.3) ] , which could increase or prolong both therapeutic effects and adverse reactions and may cause serious respiratory depression. Intervention: If concomitant use is necessary, consider increasing the buprenorphine and naloxone sublingual tablet dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal. If a CYP3A4 inducer is discontinued, consider buprenorphine and naloxone sublingual tablet dosage reduction and monitor for signs of respiratory depression. Examples: Rifampin, carbamazepine, phenytoin Antiretrovirals: Non-nucleoside reverse transcriptase inhibitors (NNRTIs) Clinical Impact: Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are metabolized principally by CYP3A4. Efavirenz, nevirapine, and etravirine are known CYP3A inducers, whereas delavirdine is a CYP3A inhibitor. Significant pharmacokinetic interactions between NNRTIs (e.g., efavirenz and delavirdine) and buprenorphine have been shown in clinical studies, but these pharmacokinetic interactions did not result in any significant pharmacodynamic effects. Intervention: Patients who are on chronic buprenorphine and naloxone sublingual tablet treatment should have their dose monitored if NNRTIs are added to their treatment regimen. Examples: efavirenz, nevirapine, etravirine, delavirdine Antiretrovirals: Protease inhibitors (PIs) Clinical Impact: Studies have shown some antiretroviral protease inhibitors (PIs) with CYP3A4 inhibitory activity (nelfinavir, lopinavir/ritonavir, ritonavir) have little effect on buprenorphine pharmacokinetic and no significant pharmacodynamic effects. Other PIs with CYP3A4 inhibitory activity (atazanavir and atazanavir/ritonavir) resulted in elevated levels of buprenorphine and norbuprenorphine, and patients in one study reported increased sedation. Symptoms of opioid excess have been found in post-marketing reports of patients receiving buprenorphine and atazanavir with and without ritonavir concomitantly. Intervention: Monitor patients taking buprenorphine and naloxone sublingual tablets and atazanavir with and without ritonavir, and reduce dose of buprenorphine and naloxone sublingual tablets if warranted. Examples: atazanavir, ritonavir Antiretrovirals: Nucleoside reverse transcriptase inhibitors (NRTIs) Clinical Impact: Nucleoside reverse transcriptase inhibitors (NRTIs) do not appear to induce or inhibit the P450 enzyme pathway, thus no interactions with buprenorphine are expected. Intervention: None Serotonergic Drugs Clinical Impact: The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Intervention: If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation and dose adjustment. Discontinue buprenorphine and naloxone sublingual tablets if serotonin syndrome is suspected. Examples: Selective serotonin reuptake inhibitors, serotonin and norepinephrine reuptake inhibitors, tricyclic antidepressants (TCAs), triptans, 5-HT3 receptor antagonists, drugs that affect the serotonin neurotransmitter system (e.g., mirtazapine, trazodone, tramadol), certain muscle relaxants (i.e., cyclobenzaprine, metaxalone), monoamine oxidase (MAO) inhibitors (those intended to treat psychiatric disorders and also others, such as linezolid and intravenous methylene blue). Monoamine Oxidase Inhibitors (MAOIs) Clinical Impact: MAOI interactions with opioids may manifest as serotonin syndrome or opioid toxicity (e.g., respiratory depression, coma). Intervention: The use of buprenorphine and naloxone sublingual tablets is not recommended for patients taking MAOIs or within 14 days of stopping such treatment. Examples: phenelzine, tranylcypromine, linezolid Muscle Relaxants Clinical Impact: Buprenorphine may enhance the neuromuscular blocking action of skeletal muscle relaxants and produce an increased degree of respiratory depression. Intervention: Monitor patients receiving muscle relaxants and buprenorphine and naloxone sublingual tablets for signs of respiratory depression that may be greater than otherwise expected and decrease the dosage of buprenorphine and naloxone sublingual tablets and/or the muscle relaxant as necessary. Due to the risk of respiratory depression with concomitant use of skeletal muscle relaxants and opioids, strongly consider recommending or prescribing an opioid overdose reversal agent, as is recommended for all patients on buprenorphine and naloxone treatment for opioid use disorder [see Dosage and Administration (2.2) , Warnings and Precautions (5.2 , 5.3) ]. Examples: Cyclobenzaprine, metaxalone Diuretics Clinical Impact: Opioids can reduce the efficacy of diuretics by ind

ADVERSE REACTIONS The following serious adverse reactions are described elsewhere in the labeling: Addiction, Abuse, and Misuse [ see Warnings and Precautions ( 5.1 )] Respiratory and CNS Depression [see Warnings and Precautions ( 5.2 ), ( 5.3 )] Neonatal Opioid Withdrawal Syndrome [see Warnings and Precautions ( 5.5 )] Adrenal Insufficiency [see Warnings and Precautions ( 5.6 )] Opioid Withdrawal [see Warnings and Precautions ( 5.7 , 5.10 )] Hepatitis, Hepatic Events [see Warnings and Precautions ( 5.8 )] Hypersensitivity Reactions [see Warnings and Precautions ( 5.9 )] Orthostatic Hypotension [see Warnings and Precautions ( 5.16 )] Elevation of Cerebrospinal Fluid Pressure [see Warnings and Precautions ( 5.17 )] Elevation of Intracholedochal Pressure [see Warnings and Precautions ( 5.18 )] Adverse events commonly observed with the sublingual/buccal administration of the buprenorphine and naloxone sublingual film are oral hypoesthesia, glossodynia, oral mucosal erythema, headache, nausea, vomiting, hyperhidrosis, constipation, signs and symptoms of withdrawal, insomnia, pain, and peripheral edema. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Camber Pharmaceuticals, Inc., at 1-866-495-8330 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The safety of buprenorphine and naloxone sublingual film is supported by clinical trials using SUBUTEX ® (buprenorphine) sublingual tablets and SUBOXONE (buprenorphine and naloxone) sublingual tablets, and other trials using buprenorphine sublingual solutions, as well as an open‐label study in 194 patients treated with buprenorphine and naloxone sublingual film administered sublingually and 188 patients treated with the film administered buccally. In total, safety data from clinical studies are available from over 3000 opioid‐dependent subjects exposed to buprenorphine at doses in the range used in the treatment of opioid dependence. Few differences in the adverse event profile were noted with regard to sublingually and bucally administered buprenorphine and naloxone sublingual film, SUBOXONE sublingual tablets, SUBUTEX sublingual tablets and a buprenorphine ethanolic sublingual solution. The most common adverse event (> 1%) associated with the sublingual administration of the buprenorphine and naloxone sublingual film was oral hypoesthesia. Other adverse events were constipation, glossodynia, oral mucosal erythema, vomiting, intoxication, disturbance in attention, palpitations, insomnia, withdrawal syndrome, hyperhidrosis, and blurred vision. The most common adverse events associated with the buccal administration were similar to those observed with sublingual administration of the film. Other adverse event data were derived from larger, controlled studies of SUBOXONE sublingual tablets and SUBUTEX sublingual tablets and of buprenorphine sublingual solution. In a comparative study of SUBOXONE sublingual tablets and SUBUTEX sublingual tablets, adverse event profiles were similar for subjects treated with 16 mg/4 mg SUBOXONE sublingual tablets or 16 mg SUBUTEX sublingual tablets. The following adverse events were reported to occur by at least 5% of patients in a 4 week study of SUBOXONE sublingual tablets and SUBUTEX sublingual tablets. Table 2. Adverse Events (≥ 5%) by Body System and Treatment Group in a 4 Week Study Body System/ Adverse Event (COSTART Terminology) SUBOXONE sublingual tablets 16 mg/4 mg/day N=107 n (%) SUBUTEX sublingual tablets 16 mg/day N=103 n (%) Placebo N=107 n (%) Body as a Whole Asthenia 7 (6.5%) 5 (4.9%) 7 (6.5%) Chills 8 (7.5%) 8 (7.8%) 8 (7.5%) Headache 39 (36.4%) 30 (29.1%) 24 (22.4%) Infection 6 (5.6%) 12 (11.7%) 7 (6.5%) Pain 24 (22.4%) 19 (18.4%) 20 (18.7%) Pain abdomen 12 (11.2%) 12 (11.7%) 7 (6.5%) Pain back 4 (3.7%) 8 (7.8%) 12 (11.2%) Withdrawal syndrome 27 (25.2%) 19 (18.4%) 40 (37.4%) Cardiovascular System Vasodilation 10 (9.3%) 4 (3.9%) 7 (6.5%) Digestive System Constipation 13 (12.1%) 8 (7.8%) 3 (2.8%) Diarrhea 4 (3.7%) 5 (4.9%) 16 (15%) Nausea 16 (15%) 14 (13.6%) 12 (11.2%) Vomiting 8 (7.5%) 8 (7.8%) 5 (4.7%) Nervous System Insomnia 15 (14%) 22 (21.4%) 17 (15.9%) Respiratory System Rhinitis 5 (4.7%) 10 (9.7%) 14 (13.1%) Skin And Appendages Sweating 15 (14%) 13 (12.6%) 11 (10.3%) Abbreviations: COSTART = Coding Symbols for Thesaurus of Adverse Reaction Terms. The adverse event profile of buprenorphine was also characterized in the dose-controlled study of a buprenorphine ethanolic solution, over a range of doses in four months of treatment. Table 3 shows adverse events reported by at least 5% of subjects in any dose group in the dose-controlled trial. Table 3. Adverse Events (≥ 5%) by Body System and Treatment Group in a 16 Week Study Body System/ Adverse Event (COSTART Terminology) Buprenorphine Dose Very Low* N=184 n (%) Low* N=180 n (%) Moderate* N=186 n (%) High* N=181 n (%) Total* N=731 n (%) Body as a Whole Abscess 9 (5%) 2 (1%) 3 (2%) 2 (1%) 16 (2%) Asthenia 26 (14%) 28 (16%) 26 (14%) 24 (13%) 104 (14%) Chills 11 (6%) 12 (7%) 9 (5%) 10 (6%) 42 (6%) Fever 7 (4%) 2 (1%) 2 (1%) 10 (6%) 21 (3%) Flu syndrome 4 (2%) 13 (7%) 19 (10%) 8 (4%) 44 (6%) Headache 51 (28%) 62 (34%) 54 (29%) 53 (29%) 220 (30%) Infection 32 (17%) 39 (22%) 38 (20%) 40 (22%) 149 (20%) Injury accidental 5 (3%) 10 (6%) 5 (3%) 5 (3%) 25 (3%) Pain 47 (26%) 37 (21%) 49 (26%) 44 (24%) 177 (24%) Pain back 18 (10%) 29 (16%) 28 (15%) 27 (15%) 102 (14%) Withdrawal syndrome 45 (24%) 40 (22%) 41 (22%) 36 (20%) 162 (22%) Digestive System Constipation 10 (5%) 23 (13%) 23 (12%) 26 (14%) 82 (11%) Diarrhea 19 (10%) 8 (4%) 9 (5%) 4 (2%) 40 (5%) Dyspepsia 6 (3%) 10 (6%) 4 (2%) 4 (2%) 24 (3%) Nausea 12 (7%) 22 (12%) 23 (12%) 18 (10%) 75 (10%) Vomiting 8 (4%) 6 (3%) 10 (5%) 14 (8%) 38 (5%) Nervous System Anxiety 22 (12%) 24 (13%) 20 (11%) 25 (14%) 91 (12%) Depression 24 (13%) 16 (9%) 25 (13%) 18 (10%) 83 (11%) Dizziness 4 (2%) 9 (5%) 7 (4%) 11 (6%) 31 (4%) Insomnia 42 (23%) 50 (28%) 43 (23%) 51 (28%) 186 (25%) Nervousness 12 (7%) 11 (6%) 10 (5%) 13 (7%) 46 (6%) Somnolence 5 (3%) 13 (7%) 9 (5%) 11 (6%) 38 (5%) Respiratory System Cough increase 5 (3%) 11 (6%) 6 (3%) 4 (2%) 26 (4%) Pharyngitis 6 (3%) 7 (4%) 6 (3%) 9 (5%) 28 (4%) Rhinitis 27 (15%) 16 (9%) 15 (8%) 21 (12%) 79 (11%) Skin and Appendages Sweat 23 (13%) 21 (12%) 20 (11%) 23 (13%) 87 (12%) Special Senses Runny eyes 13 (7%) 9 (5%) 6 (3%) 6 (3%) 34 (5%) *Sublingual solution. Doses in this table cannot necessarily be delivered in tablet form, but for comparison purposes: "Very low" dose (1 mg solution) would be less than a tablet dose of 2 mg "Low" dose (4 mg solution) approximates a 6 mg tablet dose "Moderate" dose (8 mg solution) approximates a 12 mg tablet dose "High" dose (16 mg solution) approximates a 24 mg tablet dose The safety of buprenorphine and naloxone sublingual film during treatment induction is supported by a clinical trial using 16 patients treated with buprenorphine and naloxone sublingual film and 18 treated with a buprenorphine-only sublingual film. Few differences in the adverse event profiles were noted between buprenorphine and naloxone sublingual film and the buprenorphine-only sublingual film. The most common adverse event occurring during treatment induction and the 3 days following induction using buprenorphine and naloxone sublingual film was restlessness. Other adverse events were anxiety, piloerection, stomach discomfort, irritability, headache, rhinorrhea, cold sweat, arthralgia, and lacrimation increased. Four subjects left the study early on the first day of sublingual film administration. However, there was no evidence to suggest that any of the four subjects experienced precipitated withdrawal secondary to the administration of buprenorp

CLINICAL PHARMACOLOGY 12.1 Mechanism of Action Buprenorphine and Naloxone Sublingual Tablets contain buprenorphine and naloxone. Buprenorphine is a partial agonist at the mu-opioid receptor and an antagonist at the kappa-opioid receptor. Naloxone is an opioid antagonist and produces opioid withdrawal signs and symptoms in individuals physically dependent on full opioid agonists when administered parenterally. 12.2 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, O 2 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 O 2 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. Effects on the Endocrine System Opioids inhibit the secretion of adrenocorticotropic hormone (ACTH), cortisol, and luteinizing hormone (LH) in humans [see Adverse Reactions (6.2) ] . They also stimulate prolactin, growth hormone (GH) secretion, and pancreatic secretion of insulin and glucagon. Chronic use of opioids may influence the hypothalamic-pituitary-gonadal axis, leading to androgen deficiency that may manifest as low libido, impotence, erectile dysfunction, amenorrhea, or infertility. The causal role of opioids in the clinical syndrome of hypogonadism is unknown because the various medical, physical, lifestyle, and psychological stressors that may influence gonadal hormone levels have not been adequately controlled for in studies conducted to date. Patients presenting with symptoms of androgen deficiency should undergo laboratory evaluation. Cardiac Electrophysiology Thorough QT studies with buprenorphine products have demonstrated QT prolongation ≤15 msec. 12.3 Pharmacokinetics Absorption Plasma levels of buprenorphine and naloxone increased with the sublingual dose of Buprenorphine and Naloxone Sublingual Tablets (Table 4). There was wide inter-patient variability in the sublingual absorption of buprenorphine and naloxone, but within subjects the variability was low. Both C max and AUC of buprenorphine increased in a linear fashion with the increase in dose (in the range of 4 mg to 16 mg), although the increase was not directly dose-proportional. Naloxone did not affect the pharmacokinetics of buprenorphine and both buprenorphine and naloxone sublingual tablets. At the three naloxone doses of 1, 2, and 4 mg, levels above the limit of quantitation (0.05 ng/mL) were not detected beyond 2 hours in seven of eight subjects. In one individual, at the 4 mg dose, the last measurable concentration was at 8 hours. Within each subject (for most of the subjects), across the doses there was a trend toward an increase in naloxone concentrations with increase in dose. Mean peak naloxone levels ranged from 0.11 ng/mL to 0.28 ng/mL in the dose range of 1 mg to 4 mg. Table 4. Pharmacokinetic Parameters (Mean ± SD) of Buprenorphine, Norbuprenorphine and Naloxone following Buprenorphine and Naloxone Sublingual Tablets Administration PK Parameter B uprenorphine and Naloxone Sublingual Tablets Dose (mg) 2 mg/0.5 mg 8 mg/2 mg Buprenorphine C max (ng/mL) 0.780 ± 0.323 2.58 ± 1.10 T max (hr)* 1.50 (0.75 to 3) 1.50 (0.50 to 3.03) AUC inf (ng.hr/mL) 7.651 ± 2.650 25.31 ± 9.500 t 1/2 (hr) 30.75 ± 15.04 31.94 ± 15.27 Norbuprenorphine C max (ng/mL) 0.293 ± 0.129 1.35 ± 0.977 T max (hr)* 1.25 (0.50 to 8) 1.25 (0.75 to 12) AUC inf (ng.hr/mL) 13.59 ± 4.887 52.84 ± 31.15 t 1/2 (hr) 45.84 ± 15.85 44.76 ± 28.74 Naloxone C max (pg/mL) 51.3 ± 21.1 135 ± 57.3 T max (hr)* 0.75 (0.30 to 1.50) 0.75 (0.50 to 1.25) AUC inf (pg.hr/mL) 124.2 ± 52.49 374.6 ± 132.8 t 1/2 (hr) 5.15 ± 5.28 7.65 ± 3.99 *T max is