Butrans

Boxed Warning 12/2025 Indications and Usage ( 1 ) 12/2025 Dosage and Administration ( 2.2 , 2.3 , 2.5 ) 12/2025 Warnings and Precautions ( 5.1 , 5.2 , 5.3 5.15 , 5.19 ) 12/2025

1 INDICATIONS AND USAGE BUTRANS is indicated for the management of severe and persistent pain that requires an opioid analgesic and that cannot be adequately treated with alternative options, including immediate-release opioids. Limitations of Use Because of the risks of addiction, abuse, misuse, overdose, and death, which can occur at any dosage or duration and persist over the course of therapy [see Warnings and Precautions (5.1) ] , reserve opioid analgesics, including BUTRANS, for use in patients for whom alternative treatment options are ineffective, not tolerated, or would be otherwise inadequate to provide sufficient management of pain. BUTRANS is not indicated as an as-needed (prn) analgesic. BUTRANS is a partial opioid agonist indicated for the management of severe and persistent pain that requires an opioid analgesic and that cannot be adequately treated with alternative options, including immediate-release opioids. ( 1 ) Limitations of Use Because of the risks of addiction, abuse, misuse, overdose, and death which can occur at any dosage or duration and persist over the course of therapy, reserve opioid analgesics, including BUTRANS, for use in patients for whom alternative treatment options are ineffective, not tolerated, or would be otherwise inadequate to provide sufficient management of pain. ( 1 , 5.1 ) BUTRANS is not indicated as an as-needed (prn) analgesic. ( 1 )

2 DOSAGE AND ADMINISTRATION BUTRANS should be prescribed only by healthcare professionals who are knowledgeable about the use of extended release/long-acting opioids and how to mitigate the associated risks. ( 2.1 ) BUTRANS doses of 7.5, 10, 15, and 20 mcg/hour are only for use in patients receiving, for one week or longer, daily opioid doses up to 80 mg/day of oral morphine or an equianalgesic dose of another opioid. ( 2.1 ) Use the lowest effective dosage for the shortest duration of time consistent with individual patient treatment goals. Reserve titration to higher doses of BUTRANS for patients in whom lower doses are insufficiently effective and in whom the expected benefits of using a higher dose opioid clearly outweigh the substantial risks. ( 2.1 , 5 ) Initiate the dosing regimen for each patient's individually, taking into account the patients underlying cause and severity of pain, prior analgesic treatment and response, and risk factors for addiction, abuse, and misuse. ( 2.1 , 5.1 ) Respiratory depression can occur at any time during opioid therapy, especially when initiating and following dosage increases with BUTRANS. Consider this risk when selecting an initial dose and when making dose adjustments. ( 2.1 , 5.1 ) For patients who are not opioid tolerant, initiate treatment with a 5 mcg/hour patch. ( 2.1 ) Instruct patients to wear BUTRANS for 7 days and to wait a minimum of 3 weeks before applying to the same site. ( 2.1 ) Discuss opioid overdose reversal agents and options for acquiring them with the patient and/or caregiver, both when initiating and renewing treatment with BUTRANS, especially if the patient has additional risk factors for overdose, or close contacts at risk for exposure and overdose. ( 2.2 , 5.1 , 5.2 , 5.3 ) Periodically reassess patients receiving BUTRANS to evaluate the continued need for opioid analgesics to maintain pain control, for the signs or symptoms of adverse reactions, and for the development of addiction, abuse, or misuse. ( 2.3 ) Do not rapidly reduce or abruptly discontinue BUTRANS in a physically dependent patient because rapid reduction or abrupt discontinuation of opioid analgesics has resulted in serious withdrawal symptoms, uncontrolled pain, and suicide. ( 2.5 , 5.19 ) 2.1 Important Dosage and Administration Information BUTRANS should be prescribed only by healthcare professionals who are knowledgeable about the use of extended-release/long-acting opioids and how to mitigate the associated risks. BUTRANS doses of 7.5, 10, 15, and 20 mcg/hour are only for use in patients who are receiving, for one week or longer, daily opioid doses up to 80 mg/day of oral morphine or an equianalgesic dose of another opioid. Use the lowest effective dosage for the shortest duration of time consistent with individual patient's treatment goals [see Warnings and Precautions (5) ] . Because the risk of overdose increases as opioid doses increase, reserve titration to higher doses of BUTRANS for patients in whom lower doses are insufficiently effective and in whom the expected benefits of using a higher dose opioid clearly outweigh the substantial risks. Initiate the dosing regimen for each patient individually, taking into account the patient's underlying cause and severity of pain, prior analgesic treatment and response, and risk factors for addiction, abuse, and misuse [see Warnings and Precautions (5.1) ] . Respiratory depression can occur at any time during opioid therapy, especially when initiating and following dosage increases with BUTRANS. Consider this risk when selecting an initial dose and when making dose adjustments [see Warnings and Precautions (5.2) ]. BUTRANS is for transdermal use (on intact skin) only. Each BUTRANS patch is intended to be worn for 7 days. Instruct patients not to use BUTRANS if the pouch seal is broken or the patch is cut, damaged, or changed in any way and not to cut BUTRANS. Instruct patients to avoid exposing BUTRANS to external heat sources, hot water, or p …

3 DOSAGE FORMS AND STRENGTHS BUTRANS is a rectangular or square, beige-colored system consisting of a protective liner and functional layers. BUTRANS is available in five strengths: BUTRANS 5 mcg/hour Transdermal System (dimensions: 45 mm by 45 mm) BUTRANS 7.5 mcg/hour Transdermal System (dimensions: 58 mm by 45 mm) BUTRANS 10 mcg/hour Transdermal System (dimensions: 45 mm by 68 mm) BUTRANS 15 mcg/hour Transdermal System (dimensions: 59 mm by 72 mm) BUTRANS 20 mcg/hour Transdermal System (dimensions: 72 mm by 72 mm) Transdermal system: 5 mcg/hour, 7.5 mcg/hour, 10 mcg/hour, 15 mcg/hour, and 20 mcg/hour. ( 3 )

4 CONTRAINDICATIONS BUTRANS is contraindicated in patients with: Significant respiratory depression [see Warnings and Precautions (5.2) ] Acute or severe bronchial asthma in an unmonitored setting or in the absence of resuscitative equipment [see Warnings and Precautions (5.10) ] Known or suspected gastrointestinal obstruction, including paralytic ileus [see Warnings and Precautions (5.15) ] Hypersensitivity (e.g., anaphylaxis) to buprenorphine [see Warnings and Precautions (5.18) , Adverse Reactions (6) ] Significant respiratory depression ( 4 ) Acute or severe bronchial asthma in an unmonitored setting or in the absence of resuscitative equipment ( 4 ) Known or suspected gastrointestinal obstruction, including paralytic ileus ( 4 ) Hypersensitivity to buprenorphine ( 4 )

6 ADVERSE REACTIONS The following serious adverse reactions are described elsewhere in the labeling: Addiction, Abuse, and Misuse [see Warnings and Precautions (5.1) ] Life-Threatening Respiratory Depression [see Warnings and Precautions (5.2) ] Interactions with Benzodiazepines or Other CNS Depressants [see Warnings and Precautions (5.3) ] Neonatal Opioid Withdrawal Syndrome [see Warnings and Precautions (5.4) ] Application Site Skin Reactions [see Warnings and Precautions (5.8) ] Opioid-Induced Hyperalgesia and Allodynia [see Warnings and Precautions (5.9) ] Adrenal Insufficiency [see Warnings and Precautions (5.11) ] Severe Hypotension [see Warnings and Precautions (5.12) ] Hepatotoxicity [see Warnings and Precautions (5.14) ] Gastrointestinal Effects [see Warnings and Precautions (5.15) ] Seizures [see Warnings and Precautions (5.16) ] QTc Prolongation [see Warnings and Precautions (5.17) ] Anaphylactic/Allergic Reactions [see Warnings and Precautions (5.18) ] Most common adverse reactions (≥5%) include: nausea, headache, application site pruritus, dizziness, constipation, somnolence, vomiting, application site erythema, dry mouth, and application site rash. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Knoa Pharma LLC at 1-888-726-7535 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trial 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. A total of 5,415 patients were treated with BUTRANS in controlled and open-label chronic pain clinical trials. Nine hundred twenty-four subjects were treated for approximately six months and 183 subjects were treated for approximately one year. The clinical trial population consisted of patients with persistent moderate to severe pain. The most common serious adverse drug reactions (all <0.1%) occurring during clinical trials with BUTRANS were: chest pain, abdominal pain, vomiting, dehydration, and hypertension/blood pressure increased. The most common adverse events (≥2%) leading to discontinuation were: nausea, dizziness, vomiting, headache, and somnolence. The most common adverse reactions (≥5%) reported by patients in clinical trials comparing BUTRANS 10 or 20 mcg/hour to placebo are shown in Table 2, and comparing BUTRANS 20 mcg/hour to BUTRANS 5 mcg/hour are shown in Table 3 below: Table 2: Adverse Reactions Reported in ≥5% of Patients during the Open-Label Titration Period and Double-Blind Treatment Period: Patients who were not Opioid Tolerant Open-Label Titration Period Double-Blind Treatment Period BUTRANS BUTRANS Placebo MedDRA Preferred Term (N = 1024) (N = 256) (N = 283) Nausea 23% 13% 10% Dizziness 10% 4% 1% Headache 9% 5% 5% Application site pruritus 8% 4% 7% Somnolence 8% 2% 2% Vomiting 7% 4% 1% Constipation 6% 4% 1% Table 3: Adverse Reactions Reported in ≥5% of Patients during the Open-Label Titration Period and Double-Blind Treatment Period: Opioid-Experienced Patients Open-Label Titration Period Double-Blind Treatment Period BUTRANS BUTRANS 20 BUTRANS 5 MedDRA Preferred Term (N = 1160) (N = 219) (N = 221) Nausea 14% 11% 6% Application site pruritus 9% 13% 5% Headache 9% 8% 3% Somnolence 6% 4% 2% Dizziness 5% 4% 2% Constipation 4% 6% 3% Application site erythema 3% 10% 5% Application site rash 3% 8% 6% Application site irritation 2% 6% 2% The following table lists adverse reactions that were reported in at least 2.0% of patients in four placebo/active-controlled titration-to-effect trials. Table 4: Adverse Reactions Reported in Titration-to-Effect Placebo/Active-Controlled Clinical Trials with Incidence ≥2% MedDRA Preferred Term BUTRANS (N = 392) Placebo (N = 261) Nausea 21% 6% Application site pruritus 15% 12% Dizziness 15% 7% Headache 14% 9% Somnolence 13% 4% Constipation 13% 5% Vomiting 9% 1% Application site erythema 7% 2% …

7 DRUG INTERACTIONS Table 5 Includes clinically significant drug interactions with BUTRANS. Table 5: Clinically Significant Drug Interactions with BUTRANS Benzodiazepines Clinical Impact: There have been a number of reports regarding coma and death associated with the misuse and abuse of the combination of buprenorphine and benzodiazepines. In many, but not all of these cases, buprenorphine was misused by self-injection of crushed buprenorphine tablets. 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. Intervention: Regularly evaluate patients with concurrent use of BUTRANS and benzodiazepines. Warn patients that it is extremely dangerous to self-administer benzodiazepines while taking BUTRANS, and warn patients to use benzodiazepines concurrently with BUTRANS only as directed by their physician. Benzodiazepines and 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 [see Warnings and Precautions (5.3) ] . Intervention: Reserve concomitant prescribing of these drugs for use in patients for whom alternative treatment options are inadequate. Limit dosages and durations to the minimum required. Inform patients and caregivers of this potential interaction and educate them on the signs and symptoms of respiratory depression (including sedation). If concomitant use is warranted, consider recommending or prescribing an opioid overdose reversal agent [see Dosage and Administration (2.2) , Warnings and Precautions (5.1 , 5.2 , 5.3) ] . Examples: Benzodiazepines and other sedatives/hypnotics, anxiolytics, tranquilizers, muscle relaxants, general anesthetics, antipsychotics, gabapentinoids (gabapentin or pregabalin), other opioids, 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 BUTRANS 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 BUTRANS until stable drug effects are achieved. Evaluate patients at frequent intervals for respiratory depression and sedation. If a CYP3A4 inhibitor is discontinued, consider increasing the BUTRANS dosage until stable drug effects are achieved. Assess 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 BUTRANS dosage until stable drug effects are achieved. Assess for signs of opioid withdrawal. If a CYP3 …

8 USE IN SPECIFIC POPULATIONS Pregnancy : May cause fetal harm. ( 8.1 ) Lactation : Not recommended. ( 8.2 ) Severe Hepatic Impairment : Consider use of an alternate analgesic that may permit more flexibility in dosing. ( 8.6 ) 8.1 Pregnancy Risk Summary Use of opioid analgesics for an extended period of time during pregnancy may cause neonatal opioid withdrawal syndrome [see Warnings and Precautions (5.4) ]. Available data with BUTRANS in pregnant women are insufficient to inform a drug-associated risk for major birth defects and miscarriage. In animal reproduction studies, buprenorphine caused an increase in the number of stillborn offspring, reduced litter size, and reduced offspring growth in rats at maternal exposure levels that were approximately 10 times that of human subjects who received one BUTRANS 20 mcg/hour, the maximum recommended human dose (MRHD) [see Data ]. Based on animal data, advise pregnant women of the potential risk to a fetus. The background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. Clinical Considerations Fetal/neonatal adverse reactions Use of opioid analgesics for an extended period of time during pregnancy for medical or nonmedical purposes can result in physical dependence in the neonate and neonatal opioid withdrawal syndrome shortly after birth. Neonatal opioid withdrawal syndrome presents as irritability, hyperactivity and abnormal sleep pattern, high pitched cry, tremor, vomiting, diarrhea, and failure to gain weight. The onset, duration, and severity of neonatal opioid withdrawal syndrome vary based on the specific opioid used, duration of use, timing and amount of last maternal use, and rate of elimination of the drug by the newborn. Observe newborns for symptoms of neonatal opioid withdrawal syndrome and manage accordingly [see Warnings and Precautions (5.4) ]. Labor and Delivery Opioids cross the placenta and may produce respiratory depression and psychophysiologic effects in neonates. An opioid overdose reversal agent, such as naloxone or nalmefene, must be available for reversal of opioid-induced respiratory depression in the neonate. BUTRANS is not recommended for use in women immediately prior to labor, when shorter acting analgesics or other analgesic techniques are more appropriate. Opioid analgesics, including BUTRANS, can prolong labor through actions that temporarily reduce the strength, duration, and frequency of uterine contractions. However, this effect is not consistent and may be offset by an increased rate of cervical dilatation, which tends to shorten labor. Data Animal Data Studies in rats and rabbits demonstrated no evidence of teratogenicity following BUTRANS or subcutaneous (SC) administration of buprenorphine during the period of organogenesis. Rats were administered up to one BUTRANS 20 mcg/hour every 3 days (Gestation Days 6, 9, 12, & 15) or received daily SC buprenorphine up to 5 mg/kg (Gestation Days 6-17). Rabbits were administered four BUTRANS 20 mcg/hour every 3 days (Gestation Days 6, 9, 12, 15, 18, and 19) or received daily SC buprenorphine up to 5 mg/kg (Gestation Days 6-19). No teratogenicity was observed at any dose. AUC values for buprenorphine with BUTRANS application and SC injection were approximately 110 and 140 times, respectively, that of human subjects who received the MRHD of one BUTRANS 20 mcg/hour. In a pre- and post-natal study conducted in pregnant and lactating rats, administration of buprenorphine either as BUTRANS or SC buprenorphine was associated with toxicity to offspring. Buprenorphine was present in maternal milk. Pregnant rats were administered 1/4 of one BUTRANS 5 mcg/hour every 3 days or received daily SC buprenorphine at doses o …

12.1 Mechanism of Action Buprenorphine is a partial agonist at the mu-opioid receptor and an antagonist at the kappa-opioid receptors, an agonist at delta-opioid receptors, and a partial agonist at ORL-1 (nociceptin) receptors. The contributions of these actions to its analgesic profile are unclear.

11 DESCRIPTION BUTRANS is a transdermal system providing systemic delivery of buprenorphine, a mu opioid partial agonist analgesic, continuously for 7 days. The chemical name of buprenorphine is 6,14-ethenomorphinan-7-methanol, 17-(cyclopropylmethyl)- α-(1,1-dimethylethyl)-4, 5-epoxy-18, 19-dihydro-3-hydroxy-6-methoxy-α-methyl-, [5α, 7α, (S)]. The structural formula is: The molecular weight of buprenorphine is 467.6; the empirical formula is C 29 H 41 NO 4 . Buprenorphine occurs as a white or almost white powder and is very slightly soluble in water, freely soluble in acetone, soluble in methanol and ether, and slightly soluble in cyclohexane. The pKa is 8.5 and the melting point is about 217°C. System Components and Structure Five different strengths of BUTRANS are available: 5, 7.5, 10, 15, and 20 mcg/hour (Table 6). The proportion of buprenorphine mixed in the adhesive matrix is the same in each of the five strengths. The amount of buprenorphine released from each system per hour is proportional to the active surface area of the system. The skin is the limiting barrier to diffusion from the system into the bloodstream. Table 6: BUTRANS Product Specifications Buprenorphine Delivery Rate (mcg/hour) Active Surface Area (cm 2 ) Total Buprenorphine Content (mg) BUTRANS 5 6.25 5 BUTRANS 7.5 9.375 7.5 BUTRANS 10 12.5 10 BUTRANS 15 18.75 15 BUTRANS 20 25 20 BUTRANS is a rectangular or square, beige-colored system consisting of a protective liner and functional layers. Proceeding from the outer surface toward the surface adhering to the skin, the layers are (1) a beige-colored web backing layer; (2) an adhesive rim without buprenorphine; (3) a separating layer over the buprenorphine-containing adhesive matrix; (4) the buprenorphine-containing adhesive matrix; and (5) a peel-off release liner. Before use, the release liner covering the adhesive layer is removed and discarded. Figure 1: Cross-Section Diagram of BUTRANS (not to scale). The active ingredient in BUTRANS is buprenorphine. The inactive ingredients in each system are: levulinic acid, oleyl oleate, povidone, and polyacrylate cross-linked with aluminum. Chemical Structure Fig 1

10 OVERDOSAGE Clinical Presentation Acute overdosage with buprenorphine is manifested by respiratory depression, somnolence progressing to stupor or coma, skeletal muscle flaccidity, cold and clammy skin, constricted pupils, and, in some cases, pulmonary edema, bradycardia, hypotension, hypoglycemia, partial or complete airway obstruction, atypical snoring, and death. Marked mydriasis rather than miosis may be seen due to severe hypoxia in overdose situations [see Clinical Pharmacology (12.2) ] . Toxic leukoencephalopathy has been reported after opioid overdose and can present hours, days, or weeks after apparent recovery from the initial intoxication. Treatment of Overdose In case of overdose, priorities are the re-establishment of a patent and protected airway and institution of assisted or controlled ventilation, if needed. Employ other supportive measures (including oxygen, vasopressors) in the management of circulatory shock and pulmonary edema as indicated. Cardiac arrest or arrhythmias will require advanced life support measures. Naloxone may not be effective in reversing any respiratory depression produced by buprenorphine. High doses of naloxone, 10-35 mg/70 kg, may be of limited value in the management of buprenorphine overdose. The onset of naloxone effect may be delayed by 30 minutes or more. Remove BUTRANS immediately. Because the duration of reversal would be expected to be less than the duration of action of buprenorphine from BUTRANS, carefully monitor the patient until spontaneous respiration is reliably re-established. Even in the face of improvement, continued medical monitoring is required because of the possibility of extended effects as buprenorphine continues to be absorbed from the skin. After removal of BUTRANS, the mean buprenorphine concentrations decrease approximately 50% in 12 hours (range 10-24 hours) with an apparent terminal half-life of approximately 26 hours. Due to this long apparent terminal half-life, patients may require monitoring and treatment for at least 24 hours. In an individual physically dependent on opioids, administration of an opioid overdose reversal agent may precipitate an acute withdrawal syndrome. The severity of the withdrawal symptoms experienced will depend on the degree of physical dependence and the dose of the reversal agent administered. If a decision is made to treat serious respiratory depression in the physically dependent patient, administration of the reversal agent should begin with care and by titration with smaller than usual doses of the reversal agent.

16 HOW SUPPLIED/STORAGE AND HANDLING BUTRANS Transdermal System is supplied in cartons containing 4 individually packaged systems and a pouch containing 4 Patch-Disposal Units. BUTRANS (buprenorphine) 5 mcg/hour Transdermal Systems are square, beige-colored adhesive patches measuring 45 mm by 45 mm. Each system is printed in blue with the BUTRANS logo and 5 mcg/hr and are supplied in a 4-count carton ( NDC 59011-750-04 ). BUTRANS (buprenorphine) 7.5 mcg/hour Transdermal Systems are rectangular, beige-colored adhesive patches measuring 58 mm by 45 mm. Each system is printed in blue with the BUTRANS logo and 7.5 mcg/hr and are supplied in a 4-count carton ( NDC 59011-757-04 ). BUTRANS (buprenorphine) 10 mcg/hour Transdermal Systems are rectangular, beige-colored adhesive patches measuring 68 mm by 45 mm. Each system is printed in blue with the BUTRANS logo and 10 mcg/hr and are supplied in a 4-count carton ( NDC 59011-751-04 ). BUTRANS (buprenorphine) 15 mcg/hour Transdermal Systems are rectangular, beige-colored adhesive patches measuring 72 mm by 59 mm. Each system is printed in blue with the BUTRANS logo and 15 mcg/hr and are supplied in a 4-count carton ( NDC 59011-758-04 ). BUTRANS (buprenorphine) 20 mcg/hour Transdermal Systems are square, beige-colored adhesive patches measuring 72 mm by 72 mm. Each system is printed in blue with the BUTRANS logo and 20mcg/hr and are supplied in a 4-count carton ( NDC 59011-752-04 ). Store BUTRANS securely and dispose of properly [see Patient Counseling Information (17) ] . Store at 25°C (77°F); excursions permitted between 15°C - 30°C (59°F - 86°F).