Slideshows Images Quizzes

Subutex

Last reviewed on RxList: 1/9/2017
Drug Description

SUBUTEX
(buprenorphine) Sublingual Tablet for Sublingual Administration

DESCRIPTION

SUBUTEX (buprenorphine) sublingual tablet is an uncoated oval white tablet, imprinted with a sword logo on one side and an alphanumeric imprint identifying the product and strength. It contains buprenorphine HCl and is available in two dosage strengths, 2 mg buprenorphine and 8 mg buprenorphine (as free base). Each tablet also contains lactose, mannitol, cornstarch, povidone K30, citric acid, sodium citrate and magnesium stearate.

Chemically, buprenorphine HCl is (2S)-2-[17-Cyclopropylmethyl-4,5α-epoxy-3-hydroxy-6-methoxy- 6α,14-ethano-14α-morphinan-7α-yl]-3,3-dimethylbutan-2-ol hydrochloride. It has the following chemical structure:

SUBUTEX (buprenorphine) Structural Formula Illustration

Buprenorphine HCl has the molecular formula C29H41NO4 • HCl and the molecular weight is 504.10. It is a white or off-white crystalline powder, sparingly soluble in water, freely soluble in methanol, soluble in alcohol and practically insoluble in cyclohexane.

For Consumers

What are the possible side effects of buprenorphine (Subutex)?

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Like other narcotic medicines, buprenorphine can slow your breathing. Death may occur if breathing becomes too weak.

Call your doctor at once if you have a serious side effect such as:

  • slow or shallow breathing;
  • feeling light-headed, fainting;
  • confusion, unusual thoughts or behavior; or
  • nausea, upper stomach pain, itching, loss of appetite, dark urine, clay-colored stools,...
Indications & Dosage

INDICATIONS

SUBUTEX sublingual tablet is indicated for the treatment of opioid dependence and is preferred for induction. SUBUTEX sublingual tablet should be used as part of a complete treatment plan to include counseling and psychosocial support.

Under the Drug Addiction Treatment Act (DATA) codified at 21 U.S.C. 823(g), prescription use of this product in the treatment of opioid dependence is limited to physicians who meet certain qualifying requirements, and who have notified the Secretary of Health and Human Services (HHS) of their intent to prescribe this product for the treatment of opioid dependence and have been assigned a unique identification number that must be included on every prescription.

DOSAGE AND ADMINISTRATION

SUBUTEX sublingual tablet is administered sublingually as a single daily dose. SUBUTEX sublingual tablet contains no naloxone and is preferred for use only during induction. Following induction, SUBOXONE sublingual film or SUBOXONE sublingual tablet is preferred due to the presence of naloxone when clinical use includes unsupervised administration. The use of SUBUTEX sublingual tablet for unsupervised administration should be limited to those patients who cannot tolerate SUBOXONE sublingual film or SUBOXONE sublingual tablet; for example, those patients who have been shown to be hypersensitive to naloxone.

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.

Induction

Prior to induction, consideration should be given to the type of opioid dependence (i.e., long- or shortacting opioid), the time since last opioid use, and the degree or level of opioid dependence. To avoid precipitating withdrawal, induction with SUBUTEX sublingual tablet should be undertaken when objective and clear signs of withdrawal are evident.

It is recommended that an adequate treatment dose, titrated to clinical effectiveness, should be achieved as rapidly as possible. In a one-month study, patients received 8 mg of SUBUTEX sublingual tablet on Day 1 and 16 mg SUBUTEX sublingual tablet on Day 2. From Day 3 onward, patients received either SUBOXONE sublingual tablet or SUBUTEX sublingual tablet at the same buprenorphine dose as Day 2 based on their assigned treatment. Induction in the studies of buprenorphine solution was accomplished over 3-4 days, depending on the target dose. In some studies, gradual induction over several days led to a high rate of drop-out of buprenorphine patients during the induction period.

Patients taking heroin or other short-acting opioids:

At treatment initiation, the dose of SUBUTEX sublingual tablet should be administered at least 4 hours after the patient last used opioids or preferably when moderate objective signs of opioid withdrawal appear.

Patients on methadone or other long-acting opioids:

There is little controlled experience with the transfer of methadone-maintained patients to buprenorphine. Available evidence suggests that withdrawal signs and symptoms are possible during induction onto buprenorphine. Withdrawal appears more likely in patients maintained on higher doses of methadone ( > 30 mg) and when the first buprenorphine dose is administered shortly after the last methadone dose. SUBUTEX sublingual tablet dosing should be initiated preferably when moderate objective signs of opioid withdrawal appear.

Maintenance

  • SUBOXONE is preferred for maintenance treatment.
  • Where SUBUTEX is used in maintenance in patients who cannot tolerate the presence of naloxone, the dosage of SUBUTEX should be progressively adjusted in increments / decrements of 2 mg or 4 mg buprenorphine to a level that holds the patient in treatment and suppresses opioid withdrawal signs and symptoms.
  • The maintenance dose is generally in the range of 4 mg to 24 mg buprenorphine per day depending on the individual patient. Doses higher than this have not been demonstrated to provide any clinical advantage.

Method Of Administration

SUBUTEX 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.

Clinical Supervision

Treatment should be initiated with supervised administration, progressing to unsupervised administration as the patient's clinical stability permits. The use of SUBUTEX for unsupervised administration should be limited to those patients who cannot tolerate SUBOXONE, for example those patients with known hypersensitivity to naloxone. SUBOXONE and SUBUTEX are both subject to diversion and abuse. When determining the size of 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 of the patient 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 physician's evaluation of treatment outcomes and objectives such as:

  1. Absence of medication toxicity.
  2. Absence of medical or behavioral adverse effects.
  3. Responsible handling of medications by the patient.
  4. Patient's compliance with all elements of the treatment plan (including recovery-oriented activities, psychotherapy, and/or other psychosocial modalities).
  5. Abstinence from illicit drug use (including problematic alcohol and/or benzodiazepine use).

If treatment goals are not being achieved, the physician should re-evaluate the appropriateness of continuing the current treatment.

Patients With Hepatic Impairment

Severe hepatic impairment: Consider reducing the starting and titration incremental dose by half compared to patients with normal liver function, and monitor for signs and symptoms of toxicity or overdose caused by increased levels of buprenorphine.

Moderate hepatic impairment: Although no dose adjustment is necessary for patients with moderate hepatic impairment, SUBUTEX sublingual tablets should be used with caution in these patients and prescribers should monitor patients for signs and symptoms of toxicity or overdose caused by increased levels of buprenorphine.

Mild hepatic impairment: No clinically significant differences in pharmacokinetic parameters were observed in subjects with mild hepatic impairment. No dose adjustment is needed in patients with mild hepatic impairment . [see WARNINGS AND PRECAUTIONS].

Unstable Patients

Physicians will need to decide when they cannot appropriately provide further management for particular patients. For example, some patients may be abusing or dependent on various drugs, or unresponsive to psychosocial intervention such that the physician does not feel that he/she has the expertise to manage the patient. In such cases, the physician may want to assess whether to refer the patient to a specialist or more intensive behavioral treatment environment. Decisions should be based on a treatment plan established and agreed upon with the patient at the beginning of treatment.

Patients who continue to misuse, abuse, or divert buprenorphine products or other opioids should be provided with, or referred to, more intensive and structured treatment.

Stopping Treatment

The decision to discontinue therapy with SUBOXONE or SUBUTEX after a period of maintenance should be made as part of a comprehensive treatment plan. Both gradual and abrupt discontinuation of buprenorphine has been used, but the data are insufficient to determine the best method of dose taper at the end of treatment.

HOW SUPPLIED

Dosage Forms And Strengths

SUBUTEX sublingual tablet is supplied as an uncoated oval white tablet in two dosage strengths:

  • buprenorphine 2 mg, and
  • buprenorphine 8 mg

Storage And Handling

SUBUTEX sublingual tablet is an uncoated oval white tablet, imprinted with a sword logo on one side and an alphanumeric imprint identifying the product and strength on the other side, supplied in white HDPE bottles:

NDC 12496-1278-2 (buprenorphine 2 mg/sublingual tablet; content expressed in terms of free base) - 30 tablets per bottle

NDC 12496-1310-2 (buprenorphine 8 mg/sublingual tablet; content expressed in terms of free base) - 30 tablets per bottle

Store at 25°C (77°F), excursions permitted to 15°-30°C (59°-86°F). [see USP Controlled Room Temperature].

Patients should be advised to store buprenorphine-containing medications safely and out of sight and reach of children. Destroy any unused medication appropriately. [see PATIENT INFORMATION]

Manufactured by: Reckitt Benckiser Healthcare (UK) Ltd., Hull, UK, HU8 7DS. Distributed by: Reckitt Benckiser Pharmaceuticals Inc., Richmond, VA 23235. Revised: Dec 2014.

Side Effects & Drug Interactions

SIDE EFFECTS

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.

Adverse Events In Clinical Trials

The safety of SUBUTEX sublingual tablet was supported by clinical trials using SUBUTEX sublingual tablet, SUBOXONE (buprenorphine/naloxone sublingual tablet) and other trials using buprenorphine sublingual solutions. In total, safety data were available from 3214 opioid-dependent subjects exposed to buprenorphine at doses in the range used in treatment of opioid addiction.

Few differences in adverse event profile were noted between SUBUTEX or buprenorphine administered as a sublingual solution.

The following adverse events were reported to occur by at least 5% of patients in a 4-week study (Table 1).

Table 1: Adverse Events ≥ 5% by Body System and Treatment Group in a 4-week study

Body System / Adverse Event (COSTART Terminology) N (%) N (%)
SUBUTEX 16 mg/day
N=103
Placebo
N=107
Body as a Whole
Asthenia 5 (4.9%) 7 (6.5%)
Chills 8 (7.8%) 8 (7.5%)
Headache 30 (29.1%) 24 (22.4%)
Infection 12 (11.7%) 7 (6.5%)
Pain 19 (18.4%) 20 (18.7%)
Pain Abdomen 12 (11.7%) 7 (6.5%)
Pain Back 8 (7.8%) 12 (11.2%)
Withdrawal Syndrome 19 (18.4%) 40 (37.4%)
Cardiovascular System
Vasodilation 4 (3.9%) 7 (6.5%)
Digestive System
Constipation 8 (7.8%) 3 (2.8%)
Diarrhea 5 (4.9%) 16 (15.0%)
Nausea 14 (13.6%) 12 (11.2%)
Vomiting 8 (7.8%) 5 (4.7%)
Nervous System
Insomnia 22 (21.4%) 17 (15.9%)
Respiratory System
Rhinitis 10 (9.7%) 14 (13.1%)
Skin And Appendages
Sweating 13 (12.6%) 11 (10.3%)

The adverse event profile of buprenorphine was also characterized in the dose-controlled study of buprenorphine solution, over a range of doses in four months of treatment. Table 2 shows adverse events reported by at least 5% of subjects in any dose group in the dose-controlled study.

Table 2: 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 (%)
*Sublingual solution. Doses in this table cannot necessarily be delivered in tablet form, but forcomparison 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
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

Adverse Events - Post-marketing Experience With SUBUTEX Sublingual Tablets

The most frequently reported post-marketing adverse events with SUBUTEX not observed in clinical trials, excluding drug exposure during pregnancy, was drug misuse or abuse.

DRUG INTERACTIONS

Cytochrome P-450 3A4 (CYP3A4) Inhibitors And Inducers

Buprenorphine is metabolized to norbuprenorphine primarily by cytochrome CYP3A4; therefore, potential interactions may occur when SUBUTEX sublingual tablet is given concurrently with agents that affect CYP3A4 activity. The concomitant use of SUBUTEX sublingual tablet with CYP3A4 inhibitors (e.g., azole antifungals such as ketoconazole, macrolide antibiotics such as erythromycin, and HIV protease inhibitors) should be monitored and may require dose-reduction of one or both agents.

The interaction of buprenorphine with many CYP3A4 inducers has not been studied; therefore, it is recommended that patients receiving SUBUTEX sublingual tablet be monitored for signs and symptoms of opioid withdrawal if inducers of CYP3A4 (e.g., phenobarbital, carbamazepine, phenytoin, rifampicin) are co-administered. [see CLINICAL PHARMACOLOGY]

Antiretrovirals

Three classes of antiretroviral agents have been evaluated for CYP3A4 interactions with buprenorphine. Nucleoside reverse transcriptase inhibitors (NRTIs) do not appear to induce or inhibit the P450 enzyme pathway, thus no interactions with buprenorphine are expected. Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are metabolized principally by CYP3A4. Efavirenz, nevirapine and etravirine are known CYP3A inducers whereas delaviridine 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. It is recommended that patients who are on chronic buprenorphine treatment have their dose monitored if NNRTIs are added to their treatment regimen. 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. Monitoring of patients taking buprenorphine and atazanavir with and without ritonavir is recommended, and dose reduction of buprenorphine may be warranted.

Benzodiazepines

There have been a number of post-marketing reports regarding coma and death associated with the concomitant use of buprenorphine and benzodiazepines. In many, but not all, of these cases, buprenorphine was misused by self-injection. Preclinical studies have shown that the combination of benzodiazepines and buprenorphine altered the usual ceiling effect on buprenorphine-induced respiratory depression, making the respiratory effects of buprenorphine appear similar to those of full opioid agonists. SUBUTEX sublingual tablet should be prescribed with caution to patients taking benzodiazepines or other drugs that act on the CNS, regardless of whether these drugs are taken on the advice of a physician or are being abused/misused. Patients should be warned that it is extremely dangerous to self-administer non-prescribed benzodiazepines while taking SUBUTEX sublingual tablet, and should also be cautioned to use benzodiazepines concurrently with SUBUTEX sublingual tablet only as directed by their physician.

Drug Abuse And Dependence

Controlled Substance

Buprenorphine is a Schedule III narcotic under the Controlled Substances Act.

Under the Drug Addiction Treatment Act (DATA) codified at 21 U.S.C. 823(g), prescription use of this product in the treatment of opioid dependence is limited to physicians who meet certain qualifying requirements, and who have notified the Secretary of Health and Human Services (HHS) of their intent to prescribe this product for the treatment of opioid dependence and have been assigned a unique identification number that must be included on every prescription.

Abuse

Buprenorphine, like morphine and other opioids, has the potential for being abused and is subject to criminal diversion. This should be considered when prescribing or dispensing buprenorphine in situations when the clinician is concerned about an increased risk of misuse, abuse, or diversion. Healthcare professionals should contact their state professional licensing board or state controlled substances authority for information on how to prevent and detect abuse or diversion of this product.

Patients who continue to misuse, abuse, or divert, buprenorphine products or other opioids should be provided or referred for more intensive and structured treatment.

Abuse of buprenorphine poses a risk of overdose and death. This risk is increased with the abuse of buprenorphine and alcohol and other substances, especially benzodiazepines.

The physician may be able to more easily detect misuse or diversion by maintaining records of medication prescribed including date, dose, quantity, frequency of refills, and renewal requests of medication prescribed.

Proper assessment of the patient, proper prescribing practices, periodic re-evaluation of therapy, and proper handling and storage of the medication are appropriate measures that help to limit abuse of opioid drugs.

Dependence

Buprenorphine is a partial agonist at the mu-opioid receptor and chronic administration produces physical dependence of the opioid type, characterized by moderate 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. [see WARNINGS AND PRECAUTIONS]

A neonatal withdrawal syndrome has been reported in the infants of women treated with buprenorphine during pregnancy. [see WARNINGS AND PRECAUTIONS]

FDA Logo

Report Problems to the Food and Drug Administration

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Warnings & Precautions

WARNINGS

Included as part of the PRECAUTIONS section.

PRECAUTIONS

Abuse Potential

Buprenorphine 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].

Respiratory Depression

Buprenorphine, particularly when taken by the IV route, in combination with benzodiazepines or other CNS depressants (including alcohol), has been associated with significant respiratory depression and death. Many, but not all post-marketing reports regarding coma and death associated with the concomitant use of buprenorphine and benzodiazepines involved misuse by self-injection. Deaths have also been reported in association with concomitant administration of buprenorphine with other depressants such as alcohol or other CNS depressant drugs. Patients should be warned of the potential danger of self-administration of benzodiazepines or other depressants while under treatment with SUBUTEX sublingual tablet [see DRUG INTERACTIONS].

In the case of overdose, the primary management should be the re-establishment of adequate ventilation with mechanical assistance of respiration, if required. Naloxone may be of value for the management of buprenorphine overdose. Higher than normal doses and repeated administration may be necessary.

SUBUTEX sublingual tablet should be used 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).

CNS Depression

Patients receiving buprenorphine in the presence of opioid analgesics, general anesthetics, benzodiazepines, phenothiazines, other tranquilizers, sedative/hypnotics or other CNS depressants (including alcohol) may exhibit increased CNS depression. Consider dose reduction of CNS depressants, SUBUTEX sublingual tablet, or both in situations of concomitant prescription [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 INFORMATION].

Dependence

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. Buprenorphine can be abused in a manner similar to other opioids. This should be considered when prescribing or dispensing buprenorphine in situations when the clinician is concerned about an increased risk of misuse, abuse, or diversion [see Drug Abuse and Dependence].

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 is 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, SUBUTEX sublingual tablet 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.

Allergic Reactions

Cases of hypersensitivity to buprenorphine products have been reported both in clinical trials and in the post-marketing experience. Cases of bronchospasm, angioneutrotic edema, and anaphylactic shock have been reported. The most common signs and symptoms include rashes, hives, and pruritus. A history of hypersensitivity to buprenorphine is a contraindication to the use of SUBUTEX sublingual tablet.

Precipitation Of Opioid Withdrawal Signs And Symptoms

Because of the partial agonist properties of buprenorphine, SUBUTEX sublingual tablet may precipitate opioid withdrawal signs and symptoms in individuals physically dependent on full opioid agonists if administered sublingually or parenterally before the agonist effects of other opioids have subsided.

Neonatal Withdrawal

Neonatal withdrawal has been reported in the infants of women treated with buprenorphine during pregnancy. From post-marketing reports, the time to onset of neonatal withdrawal signs and symptoms ranged from Day 1 to Day 8 of life with most cases occurring on Day 1. Adverse events associated with the neonatal withdrawal syndrome included hypertonia, neonatal tremor, neonatal agitation, and myoclonus and there have been reports of convulsions, apnea, respiratory depression and bradycardia.

Use In Opioid Na´ve Patients

There have been reported deaths of opioid na´ve individuals who received a 2 mg dose of buprenorphine as a sublingual tablet for analgesia. SUBUTEX sublingual tablet is not appropriate as an analgesic.

Use In Patients With Impaired Hepatic Function

In a pharmacokinetic study, buprenorphine plasma levels were found to be higher and the half-life was found to be longer in subjects with moderate and severe hepatic impairment, but not in subjects with mild hepatic impairment.

For patients with severe hepatic impairment, a dose adjustment is recommended, and patients with moderate or severe hepatic impairment should be monitored for signs and symptoms of toxicity or overdose caused by increased levels of buprenorphine. [see DOSAGE AND ADMINISTRATION and Use In Specific Populations].

Impairment Of Ability To Drive Or Operate Machinery

SUBUTEX sublingual tablet 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. Patients should be cautioned about driving or operating hazardous machinery until they are reasonably certain that buprenorphine therapy does not adversely affect his or her ability to engage in such activities.

Orthostatic Hypotension

Like other opioids, SUBUTEX sublingual tablet 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.

General Precautions

SUBUTEX sublingual tablet should be administered with caution in debilitated patients and those with myxedema or hypothyroidism; adrenal cortical insufficiency (e.g., Addison's disease); CNS depression or coma; toxic psychoses; prostatic hypertrophy or urethral stricture; acute alcoholism; delirium tremens; or kyphoscoliosis.

Patient Counseling Information

See FDA-approved patient labeling (Medication Guide)

Safe Use

Before initiating treatment with SUBUTEX sublingual tablet, explain the points listed below to caregivers and patients. Instruct patients to read the Medication Guide each time SUBUTEX sublingual tablet is dispensed because new information may be available.

  • Patients should be warned that it is extremely dangerous to self-administer non-prescribed benzodiazepines or other CNS depressants (including alcohol) while taking SUBUTEX sublingual tablet. Patients prescribed benzodiazepines or other CNS depressants should be cautioned to use them only as directed by their physicians [see WARNINGS AND PRECAUTIONS, DRUG INTERACTIONS].
  • Patients should be advised that SUBUTEX sublingual tablet contains an opioid that can be a target for people who abuse prescription medications or street drugs. Patients should be cautioned to keep their tablets in a safe place, and to protect them from theft.
  • Patients should be instructed to keep SUBUTEX sublingual tablet 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. Patients should be advised that if a child is exposed to SUBUTEX sublingual tablet, medical attention should be sought immediately.
  • Patients should be advised never to give SUBUTEX sublingual tablet to anyone else, even if he or she has the same signs and symptoms. It may cause harm or death.
  • Patients should be advised that selling or giving away this medication is against the law.
  • Patients should be cautioned that SUBUTEX sublingual tablet may impair the mental or physical abilities required for the performance of potentially dangerous tasks such as driving or operating hazardous 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].
  • Patients should be advised not to change the dosage of SUBUTEX sublingual tablet without consulting their physicians.
  • Patients should be advised to take SUBUTEX sublingual tablet once a day.
  • Patients should be informed that SUBUTEX sublingual tablet can cause drug dependence and that withdrawal signs and symptoms may occur when the medication is discontinued.
  • Patients seeking to discontinue treatment with buprenorphine for opioid dependence should be advised to work closely with their physicians on a tapering schedule and should be apprised of the potential to relapse to illicit drug use associated with discontinuation of opioid agonist/partial agonist medication-assisted treatment.
  • Patients should be cautioned that, like other opioids, SUBUTEX sublingual tablet may produce orthostatic hypotension in ambulatory individuals [see WARNINGS AND PRECAUTIONS].
  • Patients should inform their physicians if any other prescription medications, over-the-counter medications, or herbal preparations are prescribed or currently being used [see DRUG INTERACTIONS].
  • Women of childbearing potential who become pregnant or are planning to become pregnant, should be advised to consult their physician regarding the possible effects of using SUBUTEX sublingual tablet during pregnancy [see Specific Populations].
  • Patients should be warned that buprenorphine passes into breast milk. Breast-feeding is therefore not advised in mothers treated with buprenorphine products [see Specific Populations].
  • Patients should inform their family members that, in the event of emergency, the treating physician or emergency room staff should be informed that the patient is physically dependent on an opioid and that the patient is being treated with SUBUTEX sublingual tablet.
  • Refer to the Medication Guide for additional information regarding the counseling information.
Disposal of Unused SUBUTEX Sublingual Tablets

Unused SUBUTEX sublingual tablets should be disposed of as soon as they are no longer needed. Flush unused tablets down the toilet.

Nonclinical Toxicology

Carcinogenesis, Mutagenesis, Impairment Of Fertility

Carcinogenicity

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 recommended human daily sublingual dose of 16 mg on a mg/m² basis) 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 exposure was approximately 30 times the recommended human daily sublingual dose of 16 mg on a mg/m² basis).

Mutagenicity

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

Reproduction studies of buprenorphine in rats demonstrated no evidence of impaired fertility at daily oral doses up to 80 mg/kg/day (estimated exposure was approximately 50 times the recommended human daily sublingual dose of 16 mg on a mg/m² basis) or up to 5 mg/kg/day IM or SC (estimated exposure was approximately 3 times the recommended human daily sublingual dose of 16 mg on a mg/m² basis).

Use In Specific Populations

Pregnancy

Pregnancy Category C.

Risk Summary

There are no adequate and well-controlled studies of SUBUTEX tablets or buprenorphine in pregnant women. Limited published data on use of buprenorphine, the active ingredient in SUBUTEX, in pregnancy, have not shown an increased risk of major malformations. All pregnancies, regardless of drug exposure, have a background risk of 2-4% for major birth defects, and 15-20% 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.

SUBUTEX tablets 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

Opioid dependence in pregnancy is associated with adverse obstetrical outcomes such as low birth weight, preterm birth, and fetal death.

Fetal/Neonatal Adverse Reactions

Neonatal abstinence syndrome may occur in newborn infants of mothers who were on buprenorphine maintenance treatment. Observe newborns for poor feeding, diarrhea, irritability, tremor, rigidity, and seizures, and manage accordingly [see WARNINGS AND PRECAUTIONS].

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

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 was 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 SUBUTEX is administered to a nursing woman. The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for SUBUTEX 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 SUBUTEX 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 5-8 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 SUBUTEX sublingual tablet has not been established in pediatric patients.

Geriatric Use

Clinical studies of SUBUTEX sublingual tablet, SUBOXONE sublingual film, or SUBOXONE sublingual tablet 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 effects of hepatic impairment on the pharmacokinetics of buprenorphine were evaluated in a pharmacokinetic study. Buprenorphine is extensively metabolized in the liver and buprenorphine plasma levels were found to be higher and the half-life was found to be longer in subjects with moderate and severe hepatic impairment, but not in subjects with mild hepatic impairment.

For patients with severe hepatic impairment, a dose adjustment is recommended, and patients with moderate or severe hepatic impairment should be monitored for signs and symptoms of toxicity or overdose caused by increased levels of buprenorphine. [see DOSAGE AND ADMINISTRATION, 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.

Overdosage & Contraindications

OVERDOSE

The manifestations of acute overdose include pinpoint pupils, sedation, hypotension, respiratory depression, and death.

In the event of overdose, the respiratory and cardiac status of the patient should be monitored carefully. When respiratory or cardiac functions are depressed, primary attention should be given to the re-establishment of adequate respiratory exchange through provision of a patent airway and institution of assisted or controlled ventilation. Oxygen, IV fluids, vasopressors, and other supportive measures should be employed as indicated.

In the case of overdose, the primary management should be the re-establishment of adequate ventilation with mechanical assistance of respiration, if required. Naloxone may be of value for the management of buprenorphine overdose. Higher than normal doses and repeated administration may be necessary. The long duration of action of SUBUTEX should be taken into consideration when determining the length of treatment and medical surveillance needed to reverse the effects of an overdose. Insufficient duration of monitoring may put patients at risk.

CONTRAINDICATIONS

SUBUTEX sublingual tablet should not be administered to patients who have been shown to be hypersensitive to buprenorphine, as serious adverse reactions, including anaphylactic shock, have been reported [see WARNINGS AND PRECAUTIONS].

Clinical Pharmacology

CLINICAL PHARMACOLOGY

Mechanism Of Action

SUBUTEX sublingual tablet contains buprenorphine. Buprenorphine is a partial agonist at the mu-opioid receptor and an antagonist at the kappa-opioid receptor.

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.

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 (8-32 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, opioidexperienced 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.

Pharmacokinetics

Absorption

Plasma levels of buprenorphine increased with the sublingual dose of SUBUTEX sublingual tablet (Table 3). There was wide inter-patient variability in the sublingual absorption of buprenorphine, but within subjects the variability was low. Both Cmax and AUC of buprenorphine increased in a linear fashion with the increase in dose (in the range of 4 to 16 mg), although the increase was not directly doseproportional.

Table 3: Pharmacokinetic Parameters of Buprenorphine and Norbuprenorphine after the sublingual administration of SUBUTEX sublingual tablets

Dose Analyte Mean SD Cmax (ng/mL) T max (h) AUCinf (h•ng/mL) t½ (h)
2 mga Buprenorphine Mean 1.25 1.84 10.93 31.66
SD 0.584 0.62 3.945 12.66
Norbuprenorphine Mean 0.301 2.36 12.39 39.28
SD 0.127 2.75 4.526 20.85
8 mgb Buprenorphine Mean 2.88 1.28 28.39 35.01
SD 1.14 0.46 10.22 14.7
Norbuprenorphine Mean 1.38 1.75 50.18 44.33
SD 0.752 2.11 22.61 19.27
16 mgc Buprenorphine Mean 4.70 1.42 47.09 36.51
SD 2.16 0.50 20.03 13.99
Norbuprenorphine Mean 2.65 1.52 92.31 40.35
SD 1.62 1.34 34.74 12.07
a Source: Study Report 20-A78-AU
b Source: Study Report 20-276-SA
c Source: Study Report 20-A79-AU

Distribution

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

Metabolism

Buprenorphine undergoes both N-dealkylation to norbuprenorphine and glucuronidation. The Ndealkylation pathway is mediated primarily by 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

Elimination

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).

Buprenorphine has a mean elimination half-life from plasma ranging from 31 to 35 hours.

Drug-drug Interactions

CYP3A4 Inhibitors and Inducers: Subjects receiving SUBUTEX sublingual tablet 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 SUBUTEX sublingual tablet be monitored for signs and symptoms of opioid withdrawal if inducers of CYP3A4 (e.g., phenobarbital, carbamazepine, phenytoin, rifampicin) are co-administered [see DRUG INTERACTIONS].

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 was determined after administering a 2.0/0.5 mg SUBOXONE (buprenorphine/naloxone) sublingual tablet in subjects with varied degrees of hepatic impairment as indicated by Child-Pugh criteria. The disposition of buprenorphine in patients with hepatic impairment was 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 buprenorphine were not clinically significant. No dose 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 buprenorphine were increased (Table 4). [see WARNINGS AND PRECAUTIONS and Use In Specific Populations].

Table 4: Changes in Buprenorphine Pharmacokinetic Parameters in Subjects with Moderate and Severe Hepatic Impairment

Hepatic Impairment PK Parameters Increase in buprenorphine compared to healthy subjects
Moderate C max 8%
AUC0-last 64%
Half-life 35%
Severe C max 72%
AUC0-last 181%
Half-life 57%

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 were not clinically significant in comparison to healthy subjects without HCV infection. No dose adjustment is needed in patients with HCV infection.

Clinical Studies

Clinical data on the safety and efficacy of SUBUTEX were derived from studies of buprenorphine sublingual tablet formulations, with and without naloxone, and from studies of sublingual administration of a more bioavailable ethanolic solution of buprenorphine.

SUBUTEX tablets were studied in 1834 patients; SUBOXONE tablets (buprenorphine with naloxone) in 575 patients, and buprenorphine sublingual solutions in 2470 patients. A total of 1270 women received buprenorphine in those clinical trials. Dosing recommendations are based on data from one trial of both tablet formulations and two trials of the ethanolic solution. All trials used buprenorphine in conjunction with psychosocial counseling as part of a comprehensive addiction treatment program. There were no clinical studies conducted to assess the efficacy of buprenorphine as the only component of treatment.

In a double-blind placebo- and active-controlled study, 326 heroin-addicted subjects were randomly assigned to either SUBOXONE sublingual tablets, 16/4 mg per day; SUBUTEX sublingual tablets, 16 mg per day; or placebo sublingual tablets. For subjects randomized to either active treatment, dosing began with one 8 mg SUBUTEX on Day 1, followed by 16 mg (two 8 mg tablets) of SUBUTEX on Day 2. On Day 3, those randomized to receive SUBOXONE sublingual tablets were switched to the combination tablet. Subjects randomized to placebo received one placebo tablet on Day 1 and two placebo tablets per day thereafter for four weeks. Subjects were seen daily in the clinic (Monday through Friday) for dosing and efficacy assessments. Take-home doses were provided for weekends. Subjects were instructed to hold the medication under the tongue for approximately 5 to 10 minutes until completely dissolved. Subjects received counseling regarding HIV infection and up to one hour of individualized counseling per week. The primary study comparison was to assess the efficacy of SUBOXONE sublingual tablets and SUBUTEX sublingual tablets individually against placebo sublingual tablet. The percentage of thrice-weekly urine samples that were negative for non-study opioids was statistically higher for both SUBOXONE sublingual tablets and SUBUTEX sublingual tablets than for placebo sublingual tablets.

In a double-blind, double-dummy, parallel-group study comparing buprenorphine ethanolic solution to a full agonist active control, 162 subjects were randomized to receive the ethanolic sublingual solution of buprenorphine at 8 mg/day (a dose which is roughly comparable to a dose of 12 mg per day of SUBUTEX sublingual tablets), or two relatively low doses of active control, one of which was low enough to serve as an alternative to placebo, during a 3-10 day induction phase, a 16-week maintenance phase and a 7- week detoxification phase. Buprenorphine was titrated to maintenance dose by Day 3; active control doses were titrated more gradually.

Maintenance dosing continued through Week 17, and then medications were tapered by approximately 20%-30% per week over Weeks 18-24, with placebo dosing for the last two weeks. Subjects received individual and/or group counseling weekly.

Based on retention in treatment and the percentage of thrice-weekly urine samples negative for nonstudy opioids, buprenorphine was more effective than the low dose of the control, in keeping heroin addicts in treatment and in reducing their use of opioids while in treatment. The effectiveness of buprenorphine, 8mg per day was similar to that of the moderate active control dose, but equivalence was not demonstrated.

In a dose-controlled, double-blind, parallel-group, 16-week study, 731 subjects were randomized to receive one of four doses of buprenorphine ethanolic solution: 1 mg, 4 mg, 8 mg, and 16 mg. Buprenorphine was titrated to maintenance doses over 1-4 days and continued for 16 weeks. Subjects received at least one session of AIDS education and additional counseling ranging from one hour per month to one hour per week, depending on site.

Based on retention in treatment and the percentage of thrice-weekly urine samples negative for nonstudy opioids, the three highest tested doses were superior to the 1 mg dose. Therefore, this study showed that a range of buprenorphine doses may be effective. The 1 mg dose of buprenorphine sublingual solution can be considered to be somewhat lower than a 2 mg tablet dose. The other doses used in the study encompass a range of tablet doses from approximately 6 mg to approximately 24 mg.

Medication Guide

PATIENT INFORMATION

SUBUTEX®
(Sub-u-tex)
(buprenorphine) Sublingual Tablets

IMPORTANT:

Keep SUBUTEX in a secure place away from children. Accidental use by a child is a medical emergency and can result in death. If a child accidentally uses SUBUTEX, get emergency help right away.

Read this Medication Guide before you start taking SUBUTEX and each time you get a refill. There may be new information. This Medication Guide does not take the place of talking to your doctor. Talk to your doctor or pharmacist if you have questions about SUBUTEX.

Share the important information in this Medication Guide with members of your household.

What is the most important information I should know about SUBUTEX sublingual tablets?

  • SUBUTEX can cause serious and life-threatening breathing problems. Call your doctor right away or get emergency help if:
    • You feel faint, dizzy or confused
    • Your breathing gets much slower than is normal for you

These can be signs of an overdose or other serious problems.

  • SUBUTEX contains an opioid that can cause physical dependence.
    • Do not stop taking SUBUTEX without talking to your doctor. You could become sick with uncomfortable withdrawal signs and symptoms because your body has become used to this medicine
    • Physical dependence is not the same as drug addiction
    • SUBUTEX is not for occasional or “as needed” use
  • An overdose, and even death, can happen if you take benzodiazepines, sedatives, tranquilizers, or alcohol while using SUBUTEX. Ask your doctor what you should do if you are taking one of these.
  • Call a doctor or get emergency help right away if you:
    • Feel sleepy and uncoordinated
    • Have blurred vision
    • Have slurred speech
    • Cannot think well or clearly
    • Have slowed reflexes and breathing
  • Do not inject (“shoot-up”) SUBUTEX.
    • Injecting this medicine may cause life-threatening infections and other serious health problems.
    • Injecting SUBUTEX may cause serious withdrawal symptoms such as pain, cramps, vomiting, diarrhea, anxiety, sleep problems and cravings.
  • In an emergency, have family members tell the emergency department staff that you are physically dependent on an opioid and are being treated with SUBUTEX.

What is SUBUTEX sublingual tablet?

  • SUBUTEX is a prescription medicine used to begin treatment in adults who are addicted to (dependent on) opioid drugs (either prescription or illegal drugs), as part of a complete treatment program that also includes counseling and behavioral therapy.
  • SUBUTEX is most often used for the first 1 or 2 days to help you start with treatment.

SUBUTEX is a controlled substance (CIII) because it contains buprenorphine, which can be a target for people who abuse prescription medicines or street drugs. Keep your SUBUTEX in a safe place to protect it from theft. Never give your SUBUTEX to anyone else; it can cause death or harm them. Selling or giving away this medicine is against the law.

  • It is not known if SUBUTEX is safe or effective in children.

Who should not take SUBUTEX sublingual tablets?

Do not take SUBUTEX if you are allergic to buprenorphine.

What should I tell my doctor before taking SUBUTEX sublingual tablets?

SUBUTEX may not be right for you. Before taking SUBUTEX, tell your doctor if you:

  • Have trouble breathing or lung problems
  • Have an enlarged prostate gland (men)
  • Have a head injury or brain problem
  • Have problems urinating
  • Have a curve in your spine that affects your breathing
  • Have liver or kidney problems
  • Have gallbladder problems
  • Have adrenal gland problems
  • Have Addison's disease
  • Have low thyroid (hypothyroidism)
  • Have a history of alcoholism
  • Have mental problems such as hallucinations (seeing or hearing things that are not there)
  • Have any other medical condition
  • Are pregnant or plan to become pregnant. It is not known if SUBUTEX will harm your unborn baby. If you take SUBUTEX while pregnant, your baby may have symptoms of withdrawal at birth. Talk to your doctor if you are pregnant or plan to become pregnant.
  • Are breast feeding or plan to breast feed. SUBUTEX can pass into your milk and may harm the baby. Talk to your doctor about the best way to feed your baby if you take SUBUTEX. Breast feeding is not recommended while taking SUBUTEX.

Tell your doctor about all the medicines you take, including prescription and nonprescription medicines, vitamins and herbal supplements. SUBUTEX may affect the way other medicines work, and other medicines may affect how SUBUTEX works. Some medicines may cause serious or life-threatening medical problems when taken with SUBUTEX.

Sometimes the doses of certain medicines and SUBUTEX may need to be changed if used together. Do not take any medicine while using SUBUTEX until you have talked with your doctor. Your doctor will tell you if it is safe to take other medicines while you are using SUBUTEX.

Be especially careful about taking other medicines that may make you sleepy, such as pain medicines, tranquilizers, sleeping pills, anxiety medicines or antihistamines.

Know the medicines you take. Keep a list of them to show your doctor and pharmacist each time you get a new medicine.

How should I take SUBUTEX sublingual tablets?

Always take SUBUTEX exactly as your doctor tells you. Your doctor may change your dose after seeing how it affects you. Do not change your dose unless your doctor tells you to change it.

Do not take SUBUTEX more often than prescribed by your doctor.

If you are prescribed a dose of 2 or more SUBUTEX tablets at the same time:

Ask your doctor for instructions on the right way to take SUBUTEX tablets

Follow the same instructions every time you take a dose of SUBUTEX tablet

Put the tablets under your tongue. Let them dissolve completely.

Put the tablets under your tongue - Illustration

  • While SUBUTEX is dissolving, do not chew or swallow the tablet because the medicine will not work as well.
  • Talking while the tablet is dissolving can affect how well the medicine in SUBUTEX is absorbed.
  • If you miss a dose of SUBUTEX, take your medicine when you remember. If it is almost time for your next dose, skip the missed dose and take the next dose at your regular time. Do not take 2 doses at the same time unless your doctor tells you to. If you are not sure about your dosing, call your doctor.
  • Do not stop taking SUBUTEX suddenly. You could become sick and have withdrawal symptoms because your body has become used to the medicine. Physical dependence is not the same as drug addiction. Your doctor can tell you more about the differences between physical dependence and drug addiction. To have fewer withdrawal symptoms, ask your doctor how to stop using SUBUTEX the right way.
  • If you take too much SUBUTEX or overdose, call Poison Control or get emergency medical help right away.

What should I avoid while taking SUBUTEX sublingual tablets?

  • Do not drive, operate heavy machinery, or perform any other dangerous activities until you know how this medication affects you. Buprenorphine can cause drowsiness and slow reaction times. This may happen more often in the first few weeks of treatment when your dose is being changed, but can also happen if you drink alcohol or take other sedative drugs when you take SUBUTEX.
  • You should not drink alcohol while using SUBUTEX, as this can lead to loss of consciousness or death.

What are the possible side effects of SUBUTEX sublingual tablets?

SUBUTEX can cause serious side effects including:

  • See “What is the most important information I should know about SUBUTEX sublingual tablets?”
  • Respiratory problems. You have a higher risk of death and coma if you take SUBUTEX with other medicines, such as benzodiazepines.
  • Sleepiness, dizziness, and problems with coordination
  • Dependency or abuse
  • Liver problems. Call your doctor right away if you notice any of these signs of liver problems: Your skin or the white part of your eyes turning yellow (jaundice), urine turning dark, stools turning light in color, you have less of an appetite, or you have stomach (abdominal) pain or nausea. Your doctor should do tests before you start taking and while you take SUBUTEX.
  • Allergic reaction. You may have a rash, hives, swelling of your face, wheezing, or loss of blood pressure and consciousness. Call a doctor or get emergency help right away.
  • Opioid withdrawal. This can include: shaking, sweating more than normal, feeling hot or cold more than normal, runny nose, watery eyes, goose bumps, diarrhea, vomiting and muscle aches. Tell your doctor if you develop any of these symptoms.
  • Decrease in blood pressure. You may feel dizzy if you get up too fast from sitting or lying down.

Common side effects of SUBUTEX sublingual tablets include:

  • Headache
  • Nausea
  • Vomiting
  • Increased sweating
  • Constipation
  • Drug withdrawal syndrome
  • Decrease in sleep (insomnia)
  • Pain

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

These are not all the possible side effects of SUBUTEX sublingual tablet. For more information, ask your doctor or pharmacist.

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

How should I store SUBUTEX sublingual tablets?

  • Store SUBUTEX between 59°F and 86°R (15°C to 30°C).
  • Keep SUBUTEX in a safe place, out of the site and reach of children.

How should I dispose of unused SUBUTEX sublingual tablets?

  • Dispose of unused SUBUTEX sublingual tablets as soon as you no longer need them.
  • Flush unused tablets down the toilet.

General information about the safe and effective use of SUBUTEX sublingual tablets

Medicines are sometimes prescribed for purposes other than those listed in a Medication Guide. Do not use SUBUTEX for a condition for which it was not prescribed. Do not give SUBUTEX to other people, even if they have the same symptoms you have. It may harm them and it is against the law.

This Medication Guide summarizes the most important information about SUBUTEX sublingual tablet. If you would like more information, talk to your doctor or pharmacist. You can ask your doctor or pharmacist for information that is written for healthcare professionals.

For more information call 1-877-782-6966.

What are the ingredients in SUBUTEX sublingual tablets?

Active Ingredient:buprenorphine

Inactive Ingredients:lactose, mannitol, cornstarch, povidone K30, citric acid, sodium citrate, and magnesium stearate

Health Solutions From Our Sponsors