Fentanyl system

Boxed Warning 12/2025 Indications and Usage ( 1 ) 12/2025 Dosage and Administration ( 2.2 , 2.3 ) 12/2025 Warnings and Precautions ( 5.1, 5.2, 5.4, 5.19 , 5.21 ) 12/2025

1 INDICATIONS AND USAGE Fentanyl transdermal system is indicated for the management of severe and persistent pain in opioid-tolerant patients, that requires an opioid analgesic and that cannot be adequately treated with alternative options, including immediate-release opioids. Patients considered opioid-tolerant are those who are taking, for one week or longer, at least 60 mg morphine per day, 25 mcg transdermal fentanyl per hour, 30 mg oral oxycodone per day, 8 mg oral hydromorphone per day, 25 mg oral oxymorphone per day, 60 mg oral hydrocodone per day, or an equianalgesic dose of another opioid. 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 fentanyl transdermal system, for use in patients for whom alternative treatment options are ineffective, not tolerated, or would be otherwise inadequate to provide sufficient management of pain. Fentanyl transdermal system is not indicated as an as-needed (prn) analgesic. Fentanyl transdermal system, an opioid agonist, is indicated for the management of severe and persistent pain in opioid-tolerant patients that requires an opioid analgesic and that cannot be adequately treated with alternative options, including immediate-release opioids. (1) Patients considered opioid-tolerant are those taking, for one week or longer, at least 60 mg oral morphine per day, 25 mcg transdermal fentanyl per hour, 30 mg oral oxycodone per day, 8 mg oral hydromorphone per day, 25 mg oral oxymorphone per day, 60 mg oral hydrocodone per day, or an equianalgesic dose of another opioid. ( 2.1 ) 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 fentanyl transdermal system, 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) Fentanyl transdermal system is not indicated as an as-needed (prn) analgesic. (1)

2 DOSAGE AND ADMINISTRATION Fentanyl transdermal system should be prescribed only by healthcare providers who are knowledgeable about the use of extended-release/long-acting opioids and how to mitigate the associated risks. ( 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 fentanyl transdermal system 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 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. ( 5.1 ) Respiratory depression can occur at any time during opioid therapy, especially when initiating and following dosage increases with fentanyl transdermal system. Consider this risk when selecting an initial dose and when making dose adjustments. ( 2.1 , 5.2 ) Discuss opioid overdose reversal agents and options for acquiring them with the patient and/or caregiver, both when initiating and renewing treatment with fentanyl transdermal system, 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 , 5.4 ) Initial dose selection: consult conversion instructions. ( 2.3 ) Periodically reassess patients receiving fentanyl transdermal system 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 ( 2.4 ) Each transdermal system is intended to be worn continuously for up to 72 hours. ( 2.3 , 2.7) Adhere to instructions concerning administration and disposal of fentanyl transdermal system. ( 2.7 , 2.8 ) Mild to moderate hepatic and renal impairment: Initiate treatment with one half the usual starting dose, titrate slowly, and regularly evaluate for signs of respiratory and central nervous system depression. ( 2.5 , 2.6 ) Do not rapidly reduce or discontinue fentanyl transdermal system in a physically-dependent patient because rapid reduction or abrupt discontinuation of opioid analgesics has resulted in serious withdrawal symptoms, uncontrolled pain, and suicide. ( 2.9 , 5.21 ) 2.1 Important Dosage and Administration Instructions Fentanyl transdermal system 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. Due to the risk of respiratory depression, fentanyl transdermal system is only indicated for use in patients who are already opioid-tolerant. Discontinue or taper all other extended-release opioids when beginning fentanyl transdermal system therapy. As fentanyl transdermal system is only for use in opioid-tolerant patients, do not begin any patient on fentanyl transdermal system as the first opioid [see Indications and Usage ( 1 )] . Use the lowest effective dosage for the shortest duration of time consistent with individual patient treatment goals [see Warnings and Precautions ( 5 )] . Because the risk of overdose increases as opioid doses increase, reserve titration to higher doses of fentanyl transdermal system 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 fentanyl transdermal system. Consider thi …

3 DOSAGE FORMS AND STRENGTHS Transdermal system: Fentanyl Transdermal System 12 mcg/hour* Transdermal System (system size 4.72 cm 2 ) Fentanyl Transdermal System 25 mcg/hour Transdermal System (system size 9.44 cm 2 ) Fentanyl Transdermal System 50 mcg/hour Transdermal System (system size 18.88 cm 2 ) Fentanyl Transdermal System 75 mcg/hour Transdermal System (system size 28.32 cm 2 ) Fentanyl Transdermal System 100 mcg/hour Transdermal System (system size 37.76 cm 2 ) This lowest strength is designated as 12 mcg/hour (however, the actual strength is 12.5 mcg/hour) to distinguish it from a possible 125 mcg/hour dosage that could be prescribed by using multiple transdermal systems. Transdermal system : 12 mcg/hour, 25 mcg/hour, 50 mcg/hour, 75 mcg/hour, 100 mcg/hour. ( 3 )

4 CONTRAINDICATIONS Fentanyl transdermal system is contraindicated in: patients who are not opioid-tolerant. the management of acute or intermittent pain, or in patients who require opioid analgesia for a short period of time. the management of post-operative pain, including use after outpatient or day surgeries, (e.g., tonsillectomies). the management of mild pain. patients with significant respiratory depression [see Warnings and Precautions ( 5.12 ) ]. patients with acute or severe bronchial asthma in an unmonitored setting or in the absence of resuscitative equipment [see Warnings and Precautions ( 5.12 ) ]. patients with known or suspected gastrointestinal obstruction, including paralytic ileus [see Warnings and Precautions ( 5.19 ) ]. patients with hypersensitivity to fentanyl (e.g., anaphylaxis) or any components of the transdermal system [see Adverse Reactions ( 6.2 ) ]. Opioid non-tolerant patients. ( 4 ) Acute or intermittent pain, postoperative pain, mild pain. ( 4 ) Significant respiratory depression. ( 4 ) Acute or severe bronchial asthma in an unmonitored setting or in absence of resuscitative equipment. ( 4 ) Known or suspected gastrointestinal obstruction, including paralytic ileus. ( 4 ) Known hypersensitivity to fentanyl or any of the components of the transdermal system. ( 4 )

6 ADVERSE REACTIONS The following serious adverse reactions are discussed elsewhere in the labeling: Addiction, Abuse, and Misuse [see Warnings and Precautions ( 5.1 )] Life-Threatening Respiratory Depression [see Warnings and Precautions ( 5.2 )] Accidental Exposure [see Warnings and Precautions ( 5.3 )] Interactions with Benzodiazepines or Other Central Nervous System Depressants [see Warnings and Precautions ( 5.4 )] Neonatal Opioid Withdrawal Syndrome [see Warnings and Precautions ( 5.5 )] Opioid-Induced Hyperalgesia and Allodynia [see Warnings and Precautions ( 5.10 )] Serotonin Syndrome [see Warnings and Precautions ( 5.11 )] Adrenal Insufficiency [see Warnings and Precautions ( 5.13 )] Severe Hypotension [see Warnings and Precautions ( 5.14 )] Gastrointestinal Adverse Reactions [see Warnings and Precautions ( 5.19 )] Seizures [see Warnings and Precautions ( 5.20 )] Withdrawal [see Warnings and Precautions ( 5.21 )] Most common adverse reactions (≥5%) are nausea, vomiting, somnolence, dizziness, insomnia, constipation, hyperhidrosis, fatigue, feeling cold, anorexia, headache, and diarrhea. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, call Alvogen, Inc. at 1-866-770-3024 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 clinical practice. The safety of fentanyl transdermal system was evaluated in 216 patients who took at least one dose of fentanyl transdermal system in a multicenter, double-blind, randomized, placebo-controlled clinical trial of fentanyl transdermal system. This trial examined patients over 40 years of age with severe pain induced by osteoarthritis of the hip or knee and who were in need of and waiting for joint replacement. The most common adverse reactions (≥5%) in a double-blind, randomized, placebo-controlled clinical trial in patients with severe pain were nausea, vomiting, somnolence, dizziness, insomnia, constipation, hyperhidrosis, fatigue, feeling cold, and anorexia. Other common adverse reactions (≥5%) reported in clinical trials in patients with chronic malignant or nonmalignant pain were headache and diarrhea. Adverse reactions reported for ≥1% of fentanyl transdermal system-treated patients and with an incidence greater than placebo-treated patients are shown in Table 3 . The most common adverse reactions that were associated with discontinuation in patients with pain (causing discontinuation in ≥1% of patients) were depression, dizziness, somnolence, headache, nausea, vomiting, constipation, hyperhidrosis, and fatigue. Table 3: Adverse Reactions Reported by ≥1% of Fentanyl Transdermal System-Treated Patients and With an Incidence Greater Than Placebo-Treated Patients in 1 Double-Blind, Placebo-Controlled Clinical Trial of Fentanyl Transdermal System System/Organ Class Adverse Reaction Fentanyl Transdermal System % (N=216) Placebo % (N=200) Cardiac disorders Palpitations 4 1 Ear and labyrinth disorders Vertigo 2 1 Gastrointestinal disorders Nausea 41 17 Vomiting 26 3 Constipation 9 1 Abdominal pain upper 3 2 Dry mouth 2 0 General disorders and administration site conditions Fatigue 6 3 Feeling cold 6 2 Malaise 4 1 Asthenia 2 0 Edema peripheral 1 1 Metabolism and nutrition disorders Anorexia 5 0 Musculoskeletal and connective tissue disorders Muscle spasms 4 2 Nervous system disorders Somnolence 19 3 Dizziness 10 4 Psychiatric disorders Insomnia 10 7 Depression 1 0 Skin and subcutaneous tissue disorders Hyperhidrosis 6 1 Pruritus 3 2 Rash 2 1 Adverse reactions not reported in Table 3 that were reported by ≥1% of fentanyl transdermal system-treated adult and pediatric patients (N=1854) in 11 controlled and uncontrolled clinical trials of fentanyl transdermal system used for the treatment of chronic malignant or nonm …

7 DRUG INTERACTIONS Table 6 includes clinically significant drug interactions with fentanyl transdermal system. Table 6: Clinically Significant Drug Interactions with Fentanyl Transdermal System Inhibitors of CYP3A4 Clinical Impact: The concomitant use of fentanyl transdermal system and CYP3A4 inhibitors can increase the plasma concentration of fentanyl, resulting in increased or prolonged opioid effects particularly when an inhibitor is added after a stable dose of fentanyl transdermal system is achieved [see Warnings and Precautions ( 5.7 ) ]. After stopping a CYP3A4 inhibitor, as the effects of the inhibitor decline, the fentanyl transdermal system plasma concentration will decrease [see Clinical Pharmacology ( 12.3 ) ], resulting in decreased opioid efficacy or a withdrawal syndrome in patients who had developed physical dependence to fentanyl. Intervention: If concomitant use is necessary, consider dosage reduction of fentanyl transdermal system 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 fentanyl transdermal system dosage until stable drug effects are achieved. Evaluate for signs of opioid withdrawal. Examples: Macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g. ketoconazole), protease inhibitors (e.g., ritonavir), grapefruit juice. CYP3A4 Inducers Clinical Impact: The concomitant use of fentanyl transdermal system and CYP3A4 inducers can decrease the plasma concentration of fentanyl [see Clinical Pharmacology ( 12.3 ) ], resulting in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence to fentanyl [see Warnings and Precautions ( 5.7 ) ]. After stopping a CYP3A4 inducer, as the effects of the inducer decline, the fentanyl plasma concentration will increase [see Clinical Pharmacology ( 12.3 )] , which could increase or prolong both the therapeutic effects and adverse reactions, and may cause serious respiratory depression. Intervention: If concomitant use is necessary, consider increasing the fentanyl transdermal system dosage until stable drug effects are achieved. Evaluate for signs of opioid withdrawal. If a CYP3A4 inducer is discontinued, consider fentanyl transdermal system dosage reduction and evaluate patients at frequent intervals for signs of respiratory depression and sedation. Examples: Rifampin, carbamazepine, phenytoin Benzodiazepines and Other Central Nervous System (CNS) Depressants Clinical Impact: Due to additive pharmacologic effect, the concomitant use of benzodiazepines or other CNS depressants, including alcohol, can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death. Intervention: 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, 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 , 5.4 )] . Examples: Benzodiazepines and other sedatives/hypnotics, anxiolytics, tranquilizers, muscle relaxants, general anesthetics, antipsychotics, gabapentinoids (gabapentin or pregabalin), other opioids, alcohol. Serotonergic Drugs Clinical Impact: The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome [see Warnings and Precautions ( 5.11 ) ]. Intervention: If concomitant use is warranted, frequently evaluate the patient, particularly during treatment initiation and dose adjustment. Discontinue fentanyl transdermal system immediately if serotonin syndrome is suspected. Examples: Selective serot …

8 USE IN SPECIFIC POPULATIONS . Pregnancy : May cause fetal harm. ( 8.1 ) Lactation : Not recommended. ( 8.2 ) Severe Hepatic and Renal Impairment : Use not recommended. ( 8.6 , 8.7 ) 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 ( 5.5 ) ]. Available data with fentanyl transdermal system in pregnant women are insufficient to inform a drug-associated risk for major birth defects and miscarriage. In animal reproduction studies, fentanyl administration to pregnant rats during organogenesis was embryocidal at doses within the range of the human recommended dosing. When administered during gestation through lactation fentanyl administration to pregnant rats resulted in reduced pup survival and developmental delays at doses within the range of the human recommended dosing. No evidence of malformations were noted in animal studies completed to date [see Data ]. The estimated 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 2-4% and 15-20%, 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 ( 5.5 ) ]. Labor or Delivery Opioids cross the placenta and may produce respiratory depression and psycho-physiologic 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. Fentanyl transdermal system is not recommended for use in pregnant women during or immediately prior to labor, when use of shorter-acting analgesics or other analgesic techniques are more appropriate. Opioid analgesics, including fentanyl transdermal system, 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. Monitor neonates exposed to opioid analgesics during labor for signs of excess sedation and respiratory depression. Data Human Data There are no adequate and well-controlled studies in pregnant women. Fentanyl transdermal system should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Chronic maternal treatment with fentanyl during pregnancy has been associated with transient respiratory depression, behavioral changes, or seizures characteristic of neonatal abstinence syndrome in newborn infants. Symptoms of neonatal respiratory or neurological depression were no more frequent than expected in most studies of infants born to women treated acutely during labor with intravenous or epidural fentanyl. Transient neonatal muscular rigidity has been observed in infants whose mothers were treated with intravenous fentanyl. Animal Data No evidence of malformations or adverse effects on the fetus was reported in a published study in which pregnant rats were administered fenta …

12.1 Mechanism of Action Fentanyl is an opioid agonist. Fentanyl interacts predominately with the opioid mu-receptor. These mu-binding sites are distributed in the human brain, spinal cord, and other tissues.

11 DESCRIPTION The system contains fentanyl, an opioid agonist, for transdermal administration. The amount of fentanyl released from each system per hour is proportional to the surface area (25 mcg/hour per 9.44 cm 2 ). The composition per unit area of all transdermal system sizes is identical. * Nominal delivery rate is 12.5 mcg/hour per hour ** Nominal delivery rate per hour Strength (mcg/hour) Size (cm2) Fentanyl Content (mg) 12* 4.72 1.33 25** 9.44 2.66 50** 18.88 5.32 75** 28.32 7.99 100** 37.76 10.65 The molecular weight of fentanyl base is 336.5, and the molecular formula is C 22 H 28 N 2 O. The n-octanol: water partition coefficient is 860:1. The pKa is 8.4. The chemical name is N-Phenyl-N-(1-(2-phenylethyl)-4-piperidinyl) propanamide. The structural formula is: Fentanyl transdermal system is a rectangular translucent system with rounded corners. The product name, “FENTANYL” and dosage strength are printed in green on each system. Each system is comprised of a clear polyethylene terephthalate (PET) release liner and two functional layers. Proceeding from the outer surface toward the surface adhering to skin, these functional layers are: 1) a translucent backing layer of ethylene vinyl acetate/polyethylene terephthalate (EVA/PET) film with green print; 2) a drug-in-adhesive layer containing fentanyl, acrylate copolymer adhesive, and methyl laurate. Before use, a clear PET release liner covering the drug-in-adhesive layer is removed and discarded. Structural Formula Parts of the Fentanyl Transdermal System Patch

10 OVERDOSAGE . Clinical Presentation Acute overdose with fentanyl transdermal system can be 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 with 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 initial intoxication. Treatment of Overdose Give primary attention to the reestablishment of a patent airway and institution of assisted or controlled ventilation, if needed. Employ other supportive measures (including oxygen and vasopressors) in the management of circulatory shock and pulmonary edema as indicated. Cardiac arrest or arrhythmias will require advanced life-support measures. Once stable, examine the patient and ensure that all fentanyl transdermal systems have been removed. For clinically significant respiratory or circulatory depression secondary to opioid overdose, administer an opioid overdose reversal agent such as naloxone or nalmefene. Because the duration of opioid reversal is expected to be less than the duration of action of fentanyl in fentanyl transdermal system, carefully monitor the patient until spontaneous respiration is reliably reestablished. After fentanyl transdermal system removal, serum fentanyl concentrations decline gradually, falling about 50% in approximately 20-27 hours. Therefore, management of an overdose must be monitored accordingly, at least 72 to 96 hours beyond the overdose. In an individual physically dependent on opioids, administration of the recommended usual dosage of the opioid overdose reversal agent will 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 be initiated with care and by titration with smaller than usual doses of the reversal agent.

16 HOW SUPPLIED/STORAGE AND HANDLING Fentanyl transdermal system is supplied in cartons containing 5 individually packaged systems. See chart for information regarding individual systems. * This lowest strength is designated as 12 mcg/hour (however, the actual strength is 12.5 mcg/hour) to distinguish it from a 125 mcg/hour strength that could be prescribed by using multiple transdermal systems. Fentanyl Transdermal System Strength (mcg/hour) System Size (cm 2 ) Fentanyl Content (mg) NDC Number Fentanyl transdermal system – 12 * 4.72 1.33 47781-423-47 Fentanyl transdermal system – 25 9.44 2.66 47781-424-47 Fentanyl transdermal system – 50 18.88 5.32 47781-426-47 Fentanyl transdermal system – 75 28.32 7.99 47781-427-47 Fentanyl transdermal system – 100 37.76 10.65 47781-428-47 Store in original unopened pouch. Store up to 25°C (77°F); excursions permitted to 15-30°C (59-86°F) [see USP Controlled Room Temperature]. Store fentanyl transdermal system securely and dispose of properly [see Patient Counseling Information ( 17 ) ].