Overview
DESCRIPTION Methadone Hydrochloride Injection USP, 10 mg/mL is an opioid analgesic for parenteral use (intravenous, intramuscular or subcutaneous use). Methadone Hydrochloride Injection USP, 10 mg/mL contains methadone hydrochloride as the active pharmaceutical ingredient. Methadone hydrochloride is a white, crystalline material that is water-soluble.
Mechanism of Action
CLINICAL PHARMACOLOGY 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 involve the central nervous system and organs composed of smooth muscle. The principal therapeutic uses for methadone are for analgesia and for detoxification or maintenance 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-D-aspartate (NMDA) receptor. The contribution of NMDA receptor antagonism to methadone’s efficacy is unknown.
Indications
- INDICATIONS AND USAGE 1. Methadone Hydrochloride Injection 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 (see WARNINGS ), and persist over the course of therapy, reserve opioid analgesics, including Methadone Hydrochloride Injection, for use in patients for whom alternative treatment options are ineffective, not...
Common Doses
- 2.5 mg
- 10 mg
- 5 mg
- 100 mg
Dosage
DOSAGE AND ADMINISTRATION Important General Information 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...
Black Box Warning
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 ).
Contraindications
- CONTRAINDICATIONS Methadone Hydrochloride Injection is contraindicated in patients with: • Significant respiratory depression • Acute or severe bronchial asthma in an unmonitored setting or in the absence of resuscitative equipment • Known or suspected gastrointestinal obstruction, including paralytic ileus • Hypersensitivity to methadone hydrochloride (e.g. anaphylaxis) or any other ingredient in Methadone Hydrochloride Injection.
Side Effects
- ADVERSE REACTIONS The following serious adverse reactions are described, or described in greater detail, in other sections: • Addiction, Abuse, and Misuse (see WARNINGS ) • Life Threatening Respiratory Depression (see WARNINGS ) • QT Prolongation (see WARNINGS ) • Neonatal Opioid Withdrawal Syndrome (see WARNINGS ) • Interactions with CNS Depressants (see WARNINGS ) • Serotonin Syndrome (see WARNINGS ) • Adrenal Insufficiency (see WARNINGS ) • Severe Hypotension (see WARNINGS ) • Gastrointestinal Adverse Reactions (see WARNINGS ) • Seizures (see WARNINGS ) • Withdrawal (see WARNINGS ) •...
Interactions
- Drug Interactions Table 1: Clinically Significant Drug Interactions with Methadone Hydrochloride Injection 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 Hydrochloride Injection 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...