Methadone Hydrochloride

RECENT MAJOR CHANGES Dosage and Administration ( 2.3 , 2.6 ) 12/2025 Warnings and Precautions ( 5.1 , 5.2 , 5.13 , 5.15 ) 12/2025

1 INDICATIONS AND USAGE Methadone Hydrochloride Oral Concentrate ( Intensol TM) contains methadone, an opioid agonist indicated for the: • Management of pain severe enough to require daily, around-the-clock, long-term opioid treatment and for which alternative treatment options are inadequate. Limitations of Use o Because of the risks of addiction, abuse, and misuse with opioids, even at recommended doses, and because of the greater risks of overdose and death with long-acting opioids [see Warnings and Precautions ( 5.5 )] , reserve Methadone Hydrochloride Intensol TM for use in patients for whom alternative analgesic treatment options (e.g., non-opioid analgesics or immediate-release opioid analgesics) are ineffective, not tolerated, or would be otherwise inadequate to provide sufficient management of pain. o Methadone Hydrochloride Intensol TM are not indicated as an as-needed (prn) analgesic. • Detoxification treatment of opioid addiction (heroin or other morphine-like drugs). • Maintenance treatment of opioid addiction (heroin or other morphine-like drugs), in conjunction with appropriate social and medical services. Limitations of Use Methadone products used for the treatment of opioid addiction in detoxification or maintenance programs are subject to the conditions for distribution and use required under 21 CFR, Title 42, Sec. 8 [see Dosage and Administration ( 2.1 )] . Methadone Hydrochloride Oral Concentrate ( Intensol TM) is an opioid agonist indicated for the: • Management of pain severe enough to require daily, around-the-clock, long-term opioid treatment and for which alternative treatment options are inadequate. Limitations of Use o Because of the risks of addiction, abuse, and misuse with opioids, even at recommended doses, and because of the greater risks of overdose and death with long-acting opioids, reserve Methadone for use in patients for whom alternative treatment options (e.g., non-opioid analgesics or immediate-release opioids) are ineffective, not tolerated, or would be otherwise inadequate to provide sufficient management of pain. o Methadone is not indicated as an as-needed (prn) analgesic. • Detoxification treatment of opioid addiction (heroin or other morphine-like drugs). ( 1 ) • Maintenance treatment of opioid addiction (heroin or other morphine-like drugs), in conjunction with appropriate social and medical services. ( 1 ) Limitations of Use • Methadone products used for the treatment of opioid addiction in detoxification or maintenance programs are subject to the conditions for distribution and use required under 21 CFR, Title 42, Sec. 8. ( 1 , 2.1 )

2 DOSAGE AND ADMINISTRATION • Strongly consider recommending or prescribing an opioid overdose reversal agent (e.g., naloxone, nalmefene) at the time methadone hydrochloride oral concentrate is initiated or renewed because patients being treated with methadone may be at risk for opioid overdose during initiation or titration, or in the case of relapse to illicit use. ( 2.3 ) • Initiation of Detoxification and Maintenance Treatment : A single dose of 20 to 30 mg may be sufficient to suppress withdrawal syndrome. ( 2.4 ) • Maintenance Treatment : Clinical stability is most commonly achieved at doses between 80 to 120 mg/day. ( 2.5 ) • Do not rapidly reduce or abruptly discontinue methadone in a physically-dependent patient. ( 2.6 , 5.15 ) 2.1 Conditions for Distribution and Use of Methadone Products for the Treatment of Opioid Addiction Code of Federal Regulations, Title 42, Sec. 8 : Methadone products when used for the treatment of opioid addiction in detoxification or maintenance programs, shall be dispensed only by opioid treatment programs (and agencies, practitioners or institutions by formal agreement with the program sponsor) certified by the Substance Abuse and Mental Health Services Administration and approved by the designated state authority. Certified treatment programs shall dispense and use methadone in oral form only and according to the treatment requirements stipulated in the Federal Opioid Treatment Standards (42 CFR 8.12). See below for important regulatory exceptions to the general requirement for certification to provide opioid agonist treatment. Failure to abide by the requirements in these regulations may result in criminal prosecution, seizure of the drug supply, revocation of the program approval, and injunction precluding operation of the program. Regulatory Exceptions to the General Requirement for Certification to Provide Opioid Agonist Treatment • During inpatient care, when the patient was admitted for any condition other than concurrent opioid addiction (pursuant to 21 CFR 1306.07(c)), to facilitate the treatment of the primary admitting diagnosis. • During an emergency period of no longer than 3 days while definitive care for the addiction is being sought in an appropriately licensed facility (pursuant to 21 CFR 1306.07(b)). 2.2 Important Dosage and Administration Information Methadone is for oral administration only. The preparation must not be injected. Package in child-resistant containers and inform patients that methadone should be kept out of reach of children to prevent accidental ingestion. Consider the following important factors that differentiate methadone from other opioids: • The peak respiratory depressant effect of methadone occurs later and persists longer than its peak pharmacologic effect. • A high degree of opioid tolerance does not eliminate the possibility of methadone overdose, iatrogenic or otherwise. Deaths have been reported during conversion to methadone from chronic, high-dose treatment with other opioid agonists and during initiation of methadone treatment of addiction in subjects previously abusing high doses of other opioid agonists. • There is high interpatient variability in absorption, metabolism, and relative analgesic potency. Population-based conversion ratios between methadone and other opioids are not accurate when applied to individuals. • With repeated dosing, methadone is retained in the liver and then slowly released, prolonging the duration of potential toxicity. • Steady-state plasma concentrations are not attained until 3 to 5 days after initiation of dosing. Methadone has a narrow therapeutic index, especially when combined with other drugs. 2.3 Patient Access to an Opioid Overdose Reversal Agent for the Emergency Treatment of Opioid Overdose Inform patients and caregivers about opioid overdose reversal agents (e.g., naloxone, nalmefene) and discuss the importance of having access to an opioid overdose reversal agent. Because patients being treated wit …

3 DOSAGE FORMS AND STRENGTHS Oral Concentrate: 10 mg methadone hydrochloride (equivalent to 8.95 mg of methadone) per mL (10 mg/mL) as a red, cherry-flavored liquid concentrate in 1 fl. oz. (30 mL), 1 liter (1000 mL) or 4 liter (4000 mL) bottles 10 mg methadone hydrochloride (equivalent to 8.95 mg of methadone) per mL (10 mg/mL) as a dye-free, sugar-free, unflavored, clear liquid concentrate in 1 liter (1000 mL) bottles Oral concentrate: 10 mg/mL in 1 fl. oz. (30 mL), 1 liter (1000 mL), or 4 liter (4000 mL) bottle ( 3 )

4 CONTRAINDICATIONS Methadone Hydrochloride Intensol TM is contraindicated in patients with: • Significant respiratory depression [see Warnings and Precautions ( 5.1 )]. • Acute or severe bronchial asthma in an unmonitored setting or in the absence of resuscitative equipment [see Warnings and Precautions ( 5.8 )]. • Known or suspected gastrointestinal obstruction, including paralytic ileus [see Warnings and Precautions ( 5.13 )]. • Hypersensitivity (e.g., anaphylaxis) to methadone or any other ingredient in Methadone Hydrochloride Intensol TM [see Adverse Reactions ( 6 )]. • Significant respiratory depression ( 4 ) • Acute or severe bronchial asthma ( 4 ) • Known or suspected paralytic ileus ( 4 ) • Known hypersensitivity to methadone ( 4 )

6 ADVERSE REACTIONS The following serious adverse reactions and/or conditions are described, or described in greater detail, in other sections: • Respiratory Depression [see Warnings and Precautions ( 5.1 )] • Interactions with Benzodiazepines and other CNS Depressants [see Warnings and Precautions ( 5.2 )] • QT Prolongation [see Warnings and Precautions ( 5.3 )] • Serotonin Syndrome [see Warnings and Precautions ( 5.9 )] • Adrenal Insufficiency [see Warnings and Precautions ( 5.10 )] • Severe Hypotension [see Warnings and Precautions ( 5.11 )] • Gastrointestinal Adverse Reactions [see Warnings and Precautions ( 5.13 )] • Seizures [see Warnings and Precautions ( 5.14 )] • Withdrawal [see Warnings and Precautions ( 5.15 )] • Hypoglycemia [see Warnings and Precautions ( 5.17 )] The following adverse reactions have been identified during post-approval use of methadone. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. The major hazards of methadone are respiratory depression and, to a lesser degree, systemic hypotension. Respiratory arrest, shock, cardiac arrest, and death have occurred. The most frequently observed adverse reactions include lightheadedness, dizziness, sedation, nausea, vomiting, and sweating. These effects seem to be more prominent in ambulatory patients and in those who are not suffering severe pain. Other adverse reactions include the following: Body as a Whole: asthenia (weakness), edema, headache Cardiovascular: arrhythmias, bigeminal rhythms, bradycardia, cardiomyopathy, ECG abnormalities, extrasystoles, flushing, heart failure, hypotension, palpitations, phlebitis, QT interval prolongation, syncope, T-wave inversion, tachycardia, torsades de pointes , ventricular fibrillation, ventricular tachycardia Central Nervous System: agitation, confusion, disorientation, dysphoria, euphoria, insomnia, hallucinations, seizures, visual disturbances, congenital oculomotor disorders (nystagmus, strabismus) Endocrine: hypogonadism Gastrointestinal: abdominal pain, anorexia, biliary tract spasm, constipation, dry mouth, glossitis Hematologic: Reversible thrombocytopenia has been described in opioid addicts with chronic hepatitis. Metabolic: hypokalemia, hypomagnesemia, weight gain Musculoskeletal: decreased muscle mass and strength, osteoporosis and fractures Renal: antidiuretic effect, urinary retention or hesitancy Reproductive: amenorrhea, reduced libido and/or potency, reduced ejaculate volume, reduced seminal vesicle and prostate secretions, decreased sperm motility, abnormalities in sperm morphology Respiratory: pulmonary edema, respiratory depression Skin and Subcutaneous Tissue: pruritus, urticaria, other skin rashes, and rarely, hemorrhagic urticaria Hypersensitivity: Anaphylaxis has been reported with ingredients contained in Methadone Hydrochloride Intensol TM. Serotonin syndrome: Cases of serotonin syndrome, a potentially life-threatening condition, have been reported during concomitant use of opioids with serotonergic drugs. Adrenal insufficiency: Cases of adrenal insufficiency have been reported with opioid use, more often following greater than one month of use. Androgen deficiency: Cases of androgen deficiency have occurred with chronic use of opioids [see Clinical Pharmacology ( 12.2 )] . Hypoglycemia: Cases of hypoglycemia have been reported in patients taking methadone [see Warnings and Precautions ( 5.17 )] . Opioid-induced esophageal dysfunction (OIED): Cases of OIED have been reported in patients taking opioids and may occur more frequently in patients taking higher doses of opioids, and/or in patients taking opioids longer term [see Warnings and Precautions ( 5.13 )] . Most Common Adverse Reactions are: lightheadedness, dizziness, sedation, nausea, vomiting, and sweating. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Hikma Pharmaceuticals USA …

7 DRUG INTERACTIONS 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, increases the risk of respiratory depression, profound sedation, coma, and death. Intervention: For Patients Being Treated for Pain 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. Follow patients closely for signs of respiratory depression and sedation [see Warnings and Precautions ( 5.2 )] . If concomitant use is warranted, consider prescribing naloxone for the emergency treatment of opioid overdose [see Warnings and Precautions ( 5.1 , 5.2 , 5.5 )] . For Patients Being Treated for Opioid Addiction Cessation of benzodiazepines or other CNS depressants is preferred in most cases of concomitant use. In some cases, monitoring in a higher level of care for taper may be appropriate. In others, gradually tapering a patient off of a prescribed benzodiazepine or other CNS depressant or decreasing to the lowest effective dose may be appropriate. Before co-prescribing benzodiazepines for anxiety or insomnia, ensure that patients are appropriately diagnosed and consider alternative medications and non-pharmacologic treatments [see Warnings and Precautions ( 5.2 )] . If concomitant use is warranted, strongly consider recommending or prescribing an opioid overdose reversal agent, as is recommended for all patients in treatment for opioid use disorder [see Warnings and Precautions ( 5.1 )] . Examples: Alcohol, benzodiazepines, and other sedatives/hypnotics, anxiolytics, tranquilizers, muscle relaxants, general anesthetics, antipsychotics, gabapentinoids (gabapentin or pregabalin), other opioids. Inhibitors of CYP3A4, CYP2B6, CYP2C19, CYP2C9, or CYP2D6 Clinical Impact: Methadone undergoes hepatic N-demethylation by several cytochrome P450 (CYP) isoforms, including CYP3A4, CYP2B6, CYP2C19, CYP2C9, and CYP2D6. The concomitant use of methadone and CYP3A4, CYP2B6, CYP2C19, CYP2C9, or CYP2D6 inhibitors can increase the plasma concentration of methadone, resulting in increased or prolonged opioid effects, and may result in a fatal overdose, particularly when an inhibitor is added after a stable dose of methadone is achieved. These effects may be more pronounced with concomitant use of drugs that inhibit more than one of the CYP enzymes listed above. After stopping a CYP3A4, CYP2B6, CYP2C19, CYP2C9, or CYP2D6 inhibitor, as the effects of the inhibitor decline, the methadone plasma concentration can decrease [see Clinical Pharmacology ( 12.3 )] , resulting in decreased opioid efficacy or withdrawal symptoms in patients physically dependent on methadone. Intervention: If concomitant use is necessary, consider dosage reduction of methadone until stable drug effects are achieved. Monitor patients for respiratory depression and sedation at frequent intervals. If a CYP3A4, CYP2B6, CYP2C19, CYP2C9, or CYP2D6 inhibitor is discontinued, follow patients for signs of opioid withdrawal and consider increasing the methadone dosage until stable drug effects are achieved. Examples: Macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g., ketoconazole), protease inhibitors (e.g., ritonavir), fluconazole, fluvoxamine, some selective serotonin reuptake inhibitors (SSRIs) (e.g., sertraline, fluvoxamine) Inducers of CYP3A4, CYP2B6, CYP2C19, or CYP2C9 Clinical Impact: The concomitant use of methadone and CYP3A4, CYP2B6, CYP2C19, or CYP2C9 inducers can decrease the plasma concentration of methadone [see Clinical Pharmacology ( 12.3 )] , resulting in decreased efficacy or onset of withdrawal symptoms in patients physically dependent on methadone. These effects could be more pronounced with concomitant use of drugs that can induce multiple CYP enzymes. After stopping a CYP3A4, CYP2B6, CYP2C19, or CYP2C9 ind …

8 USE IN SPECIFIC POPULATIONS • Lactation : Monitor breastfed infants for increased drowsiness and breathing difficulties. ( 8.2 ) 8.1 Pregnancy Risk Summary The majority of available data from clinical trials, observational studies, case series, and case reports on methadone use in pregnancy do not indicate an increased risk of major malformations specifically due to methadone. Pregnant women involved in methadone maintenance programs have been reported to have improved prenatal care leading to reduced incidence of obstetric and fetal complications and neonatal morbidity and mortality when compared to women using illicit drugs. Several factors, including maternal use of illicit drugs, nutrition, infection and psychosocial circumstances, complicate the interpretation of investigations of the children of women who take methadone during pregnancy. Information is limited regarding dose and duration of methadone use during pregnancy, and most maternal exposure in these studies appears to occur after the first trimester of pregnancy ( see Data ). Neonatal opioid withdrawal syndrome (NOWS) is an expected and treatable outcome of prolonged use of opioids during pregnancy [see Warnings and Precautions ( 5.6 )] . In published animal reproduction studies, methadone administered subcutaneously during the early gestational period produced neural tube defects (i.e., exencephaly and cranioschisis) in the hamster at doses 2 times the human daily oral dose of 120 mg/day on a mg/m 2 basis (HDD) and in mice at doses equivalent to the HDD. Administration of methadone to pregnant animals during organogenesis and through lactation resulted decreased litter size, increased pup mortality, decreased pup body weights, developmental delays, and long-term neurochemical changes in the brain of offspring which correlate with altered behavioral responses that persist through adulthood at exposures comparable to and less than the HDD. Administration of methadone to male rodents prior to mating with untreated females resulted in increased neonatal mortality and significant differences in behavioral tests in the offspring at exposures comparable to and less than the HDD ( see Data ). Based on animal data, advise pregnant women of the potential risk to a fetus. 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% to 4% and 15% to 20%, respectively. Clinical Considerations Disease-Associated Maternal and Embryo-Fetal Risk : Untreated opioid addiction in pregnancy is associated with adverse obstetrical outcomes such as low birth weight, preterm birth, and fetal death. In addition, untreated opioid addiction often results in continued or relapsing illicit opioid use. Dosage Adjustment During Pregnancy : Dosage adjustment using higher doses or administering the daily dose in divided doses may be necessary in pregnant women treated with methadone. Pregnant women appear to have significantly lower trough plasma methadone concentrations, increased plasma methadone clearance, and shorter methadone half-life than after delivery [see Dosage and Administration ( 2.9 ), Clinical Pharmacology ( 12.3 )] . Withdrawal signs and symptoms should be closely monitored and the dose adjusted as necessary. Fetal/Neonatal Adverse Reactions : Neonatal opioid withdrawal syndrome may occur in newborn infants of mothers who are receiving treatment with methadone. Neonatal opioid withdrawal syndrome presents as irritability, hyperactivity and abnormal sleep pattern, high-pitched cry, tremor, vomiting, diarrhea, and/or failure to gain weight. Signs of neonatal withdrawal usually occur in the first days after birth. The duration and severity of neonatal opioid withdrawal syndrome may vary. Observe newborns …

Mechanism of Action Methadone hydrochloride is a mu-agonist; a synthetic opioid analgesic with multiple actions qualitatively similar to those of morphine, the most prominent of which involves the central nervous system and organs composed of smooth muscle. The principal therapeutic uses for methadone are analgesia and detoxification or maintenance treatment in opioid addiction. The methadone abstinence syndrome, although qualitatively similar to that of morphine, differs in that the onset is slower, the course is more prolonged, and the symptoms are less severe. Some data also indicate that methadone acts as an antagonist at the N-methyl-Daspartate (NMDA) receptor. The contribution of NMDA receptor antagonism to methadone’s efficacy is unknown.

11 DESCRIPTION Methadone hydrochloride oral concentrate, USP contains methadone, an opioid agonist, and is available as a cherry-flavored liquid concentrate for oral administration. Methadone hydrochloride oral concentrate, USP sugar-free is a dye-free, sugar-free, unflavored liquid concentrate of methadone hydrochloride for oral administration. Methadone hydrochloride is chemically described as 6-(dimethylamino)-4,4-diphenyl-3-heptone hydrochloride. Methadone hydrochloride, USP is a fine white powder. It is very soluble in water, soluble in isopropanol and in chloroform, and practically insoluble in ether and in glycerine. It is present in methadone hydrochloride oral concentrate as the racemic mixture. Methadone hydrochloride has a melting point of 235°C, a pKa of 8.25 in water at 20°C, a solution (1 part per 100) pH between 4.5 and 6.5, a partition coefficient of 117 at pH 7.4 in octanol/water and a molecular weight of 345.91. Its structural formula is C 21 H 27 NO•HCl. Each liquid concentrate contains 10 mg of methadone hydrochloride (equivalent to 8.95 mg of methadone) per mL and the following inactive ingredients: artificial cherry flavor, sorbic acid, potassium sorbate, FD&C Red No. 40, D&C Red No. 33, poloxamer 188, propylene glycol, glycerin, sucrose, and purified water. Other ingredients of methadone hydrochloride oral concentrate, USP (dye-free, sugar-free, unflavored): citric acid anhydrous, purified water, sodium benzoate. Chemical Structure

10 OVERDOSAGE Clinical Presentation Acute overdosage with methadone 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 )] . In severe overdosage, particularly by the intravenous route, apnea, circulatory collapse, cardiac arrest, and death may occur. Methadone overdosage is associated with rhabdomyolysis. Seek medical attention, especially if abuse/misuse results in prolonged immobilization. Toxic leukoencephalopathy has been reported after opioid overdose, and can present hours, days, or weeks after apparent recovery from the initial intoxication. Hearing loss has been reported after methadone overdose, in some cases permanent. Treatment of Overdose In the case of overdose, priorities are the reestablishment of a patent and protected 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 techniques. 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 methadone, carefully monitor the patient until spontaneous respiration is reliably established. If the response to an opioid overdose reversal agent is suboptimal or not sustained, administer additional reversal agent as directed in the product’s prescribing information. In an individual physically dependent on opioids, the administration of the usual dose of an 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 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 Methadone hydrochloride oral concentrate, USP 10 mg per mL (10 mg/mL) is supplied as a red, cherry-flavored liquid concentrate, as follows: 1 fl. oz. Bottle (30 mL)................ NDC 66689-694-30 (Supplied with calibrated dropper); 1 Liter Bottle (1000 mL).............. NDC 66689-694-79 4 Liter Bottle (4000 mL).............. NDC 66689-694-88 Methadone hydrochloride oral concentrate, USP 10 mg per mL (10 mg/mL) is supplied as a dye-free, sugar-free, unflavored liquid concentrate, as follows: 1 Liter Bottle (1000 mL).............. NDC 66689-695-79 Dispense in tight containers, protected from light. Store at 20° to 25°C (68° to 77°F) [see USP Controlled Room Temperature]. Store methadone hydrochloride oral concentrate securely and dispose of properly [see Patient Counseling Information ( 17 )] .