Last reviewed 2026-04-20 · How we verify

Methadone Hydrochloride (METHADONE)

Methadone is a synthetic opioid that acts as a mu-agonist, providing analgesia and aiding in opioid addiction management.

Methadone Hydrochloride, marketed by Specgx LLC, is a synthetic opioid primarily indicated for severe and persistent pain management, holding a significant position in the opioid analgesic market. Its key strength lies in its dual mechanism as a mu-agonist, which not only provides effective analgesia but also aids in managing opioid addiction, setting it apart in the therapeutic landscape. The primary risk is the key composition patent expiry in 2028, which could lead to increased competition from generic versions and potentially erode market share.

At a glance

Mechanism of action

Methadone works by binding to the mu-opioid receptors in the brain, which helps reduce pain and manage withdrawal symptoms in opioid addiction. It also has a slower onset and more prolonged course compared to morphine.

Approved indications

• Severe and Persistent Pain Management
• Temporary Treatment of Opioid Dependence

Boxed warnings

• WARNING: SERIOUS AND LIFE-THREATENING RISKS FROM USE OF METHADONE HYDROCHLORIDE INJECTION Addiction, Abuse, and Misuse Because the use of Methadone Hydrochloride Injection exposes patients and other users to the risks of opioid addiction, abuse, and misuse, which can lead to overdose and death, assess each patient’s risk prior to prescribing and reassess all patients regularly for the development of these behaviors and conditions (see WARNINGS ). Life-Threatening Respiratory Depression Serious, life-threatening, or fatal respiratory depression may occur with use of Methadone Hydrochloride Injection, especially during initiation or following a dosage increase. To reduce the risk of respiratory depression, proper dosing and titration of Methadone Hydrochloride Injection are essential (see WARNINGS ). Neonatal Opioid Withdrawal Syndrome (NOWS) Neonatal opioid withdrawal syndrome (NOWS) is an expected and treatable outcome of use of Methadone Hydrochloride Injection during pregnancy. NOWS may be life-threatening if not recognized and treated in the neonate. The balance between the risks of NOWS and the benefits of maternal Methadone Hydrochloride Injection use may differ based on the risks associated with the mother’s underlying condition, pain, or addiction. Advise the patient of the risk of NOWS so that appropriate planning for management of the neonate can occur (see WARNINGS ). Managing Risks From Concomitant Use With Benzodiazepines Or Other CNS Depressants Concomitant use of opioids with benzodiazepines or other central nervous system (CNS) depressants, including alcohol, may result in profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing of Methadone Hydrochloride Injection and benzodiazepines or other CNS depressants for use in patients for whom alternative treatment options are inadequate (see WARNINGS , PRECAUTIONS ). Life-Threatening QT Prolongation QT interval prolongation and serious arrhythmia (torsades de pointes) have occurred during treatment with methadone. Most cases involve patients being treated for pain with large, multiple daily doses of methadone, although cases have been reported in patients receiving doses commonly used for maintenance treatment of opioid addiction. Closely monitor patients with risk factors for development of prolonged QT interval, a history of cardiac conduction abnormalities, and those taking medications affecting cardiac conduction for changes in cardiac rhythm during initiation and titration of Methadone Hydrochloride Injection (see WARNINGS ). Interactions with Drugs Affecting Cytochrome P450 Isoenzymes The concomitant use of Methadone Hydrochloride Injection with all cytochrome P450 3A4, 2B6, 2C19, 2C9 or 2D6 inhibitors may result in an increase in methadone plasma concentrations, which could cause potentially fatal respiratory depression. In addition, discontinuation of concomitantly used cytochrome P450 3A4 2B6, 2C19, or 2C9 inducers may also result in an increase in methadone plasma concentration. Follow patients closely for respiratory depression and sedation and consider dosage reduction with any changes of concomitant medications that result in an increase in methadone levels (see WARNINGS , PRECAUTIONS: Drug Interactions ). Conditions for Distribution and Use of Methadone Products for the Treatment of Opioid Addiction For detoxification and maintenance of opioid dependence, methadone should be administered in accordance with the treatment standards cited in 42 CFR Section 8, including limitations on unsupervised administration (see INDICATIONS AND USAGE ).

Common side effects

• Respiratory depression
• Systemic hypotension
• Respiratory arrest
• Shock
• Cardiac arrest
• Death
• Lightheadedness
• Dizziness
• Sedation
• Nausea
• Vomiting
• Sweating

Drug interactions

• Inhibitors of CYP3A4, CYP2B6, CYP2C19, CYP2C9, or CYP2D6
• Inducers of CYP3A4, CYP2B6, CYP2C19, or CYP2C9

Key clinical trials

• Methadone Pharmacokinetics in Cardiac Surgery (PHASE4)
• Remotely Observed Methadone Evaluation II (PHASE2)
• Outcome Inference in the Sensory Preconditioning Task in Opioid-Use Disorder
• A RCT Using Methadone in the Management of Post-Operative Pain in Total Knee Replacement (PHASE4)
• Predicting and Preventing Adverse Maternal and Child Outcomes of Opioid Use Disorder in Pregnancy
• Efficacy and Safety of Sustained-release Dexamphetamine in Patients With Moderate to Severe Cocaine Use Disorder (PHASE2)
• Cannabidiol in Opioid Use Disorder and Chronic Pain (EARLY_PHASE1)
• Symptom-inhibited Fentanyl Induction (PHASE4)

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

• Methadone Hydrochloride CI brief — competitive landscape report
• Methadone Hydrochloride updates RSS · CI watch RSS
• Specgx Llc portfolio CI