METHADOSE DISPERSIBLE Methadone Hydrochloride 40 mg Tablet, 100-count — NDC 0406-0540-34 (Billing 00406-0540-34)
This is a package of 100 tablets of METHADOSE DISPERSIBLE Methadone Hydrochloride 40 mg Tablet from SpecGx LLC, marketed since Apr 1993 and currently FDA-listed. It is this product's only package size.
NDC database record
One package, one record: these facts belong to NDC 0406-0540-34 alone.
- Record
- FDA NDC Directory package listing · Human prescription drug
- Code segments
- 0406 labeler · 0540 product · 34 package
- Package marketed since
- Apr 29, 1993
- Sample package
- No — commercial package
- Listing certified through
- Dec 31, 2027
- Billing quantity
- 100 EA per package
- Barcode (UPC-A, from the NDC)
- 3 0406054034 7
- Medicaid fills, this package
- 7,091 prescriptions in the last four reported quarters
- FDA record last changed
- Aug 20, 2026
Other active recalls for Methadone Hydrochloride (different manufacturers) — 1 · tap to view
Identity & classification
Regulatory identifiers FDA, NLM and CMS codes for this package
Drug-database identifiers Medi-Span GPI and First Databank GCN / HICL / AHFS classification
- GSN (GCN sequence number): 023767
- GCN: 16423
- HICL (First Databank): 001745
- AHFS class code: 28:08.08.00
- RxCUI (RxNorm): 864978
Where does this data come from?
- FDA openFDA NDC Directory · synced Oct 8, 2026
- FDA label on DailyMed · label index refreshed Oct 8, 2026
- RxNorm (NLM RxNav) · catalog refreshed Oct 1, 2026
- Medi-Span GPI (licensed)
- First Databank (licensed) · refreshed Oct 8, 2026
RxNorm drug class
This medicine belongs to the Opioid Agonist class.
Where does this data come from?
- RxClass (NLM) · catalog refreshed Oct 1, 2026
Clinical
Methadone is used to relieve severe pain. Methadone also is used to treat opioid addiction (physical and psychological reliance on a chemical found in prescription and street drugs). Methadone is in a class of medications called opiate (narcotic) analgesics. Methadone works to treat pain by changing the way the brain and nervous system respond to pain. It works to treat people who were addicted to opiate drugs by producing similar effects and preventing withdrawal symptoms.
Read the full MedlinePlus article ↗- Depending on the product, it treats severe, long-term pain or opioid addiction, as detox or maintenance. Injection is for pain or short-term use when you can't take pills. It isn't...
- Always use a graduated measuring device, never a kitchen spoon. Double-check the dose in mg versus mL and the strength on your bottle. If you're unsure, ask me before you take it.
- Dizziness, lightheadedness, sleepiness, nausea, vomiting, sweating and constipation are most common. Call for help if breathing slows, you faint, or your heartbeat feels irregular.
- Don't mix them unless your prescriber says so. Alcohol, benzodiazepines and similar drugs can cause deep sedation, slow breathing, coma and death.
Patient education
Supplement & herbal interactions
Where does this data come from?
- MedlinePlus (NLM) · refreshed Oct 8, 2026
- FDA label on DailyMed · label index refreshed Oct 8, 2026
Ask a licensed pharmacist directly — free, answered by our team.
Pricing
A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.
| Price system | Per each | Per package |
|---|---|---|
| Retail pharmacies payNADAC · weekly | Not in the retail survey — common for institutional, discontinued, or low-volume packs. | |
| Medicaid paysCMS SDUD · 12 mo | $1.70 | $169.57 / 100 tablets |
| Medicare drug plans payPart D · quarterly | No Part D plan price is available for this NDC in our data. | |
Where does this data come from?
- CMS NADAC weekly file
- CMS ASP pricing files · refreshed Sep 20, 2026
- CMS Medicaid State Drug Utilization Data · through Q1 2026
- CMS Part D plan pricing files · refreshed Sep 24, 2026
- VA National Acquisition Center price file
Packaging — all sizes for this product
| Package NDC | Description | Marketing start | Marketing end | Status |
|---|---|---|---|---|
| 00406-0540-34 You're viewing this Main listing | 100 TABLET in 1 BOTTLE | 1993-04-29 | — | Active |
Therapeutic equivalents
| Product | Labeler | Pack | NADAC/unit | TE | Status | Price vs. this |
|---|---|---|---|---|---|---|
| Diskets 40 mg 00054-4538-25 | Hikma | 100 tablets | — | AA | FDA listed | — |
| Methadose Dispersible 40 mgthis 00406-0540-34 | SpecGx | 100 tablets | — | AA | FDA listed | — |
| Methadone Hydrochloride 40 mg 00406-2540-01 | SpecGx | 100 tablets | — | AA | FDA listed | — |
| Methadone Hydrochloride 40 mg 66689-0898-40 | VistaPharm, | 100 tablets | — | AA | FDA listed | — |
Where does this data come from?
- FDA openFDA NDC Directory · synced Oct 8, 2026
- FDA Orange Book · refreshed Oct 3, 2026
- CMS NADAC weekly file
Availability & generic status
This product is an FDA-approved generic. Other versions of the same drug are listed under Therapeutic equivalents, least expensive first.
Where does this data come from?
- FDA Orange Book · refreshed Oct 3, 2026
What it looks like
Where does this data come from?
- FDA label on DailyMed · label index refreshed Oct 8, 2026
Inactive Ingredients / Excipients
Inactive ingredients, also called excipients, are components of the drug product other than the active ingredient. They may include fillers, dyes, coatings, preservatives, flavors, or other formulation ingredients.
🧪 Avoiding an ingredient? See Methadone inactive ingredients by manufacturer: every current product's list side by side, so you can ask your pharmacy for the version that does not list it.
💡 Tap an ingredient (hover on desktop) to see what it is and why it’s used.
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UNII O7TSZ97GEP
A mineral compound that serves as a filler and binding agent in tablets and capsules. It adds bulk to the medicine and helps hold ingredients together during manufacturing.
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UNII 70097M6I30
Magnesium stearate is a salt made from magnesium and stearic acid, a fatty substance. It's used in tablets and capsules as a lubricant and glidant to help ingredients flow smoothly during manufacturing and prevent sticking.
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UNII OP1R32D61U
Microcrystalline cellulose is a purified form of cellulose, a natural fiber from plant sources. It acts as a binder and filler in tablets and capsules, helping hold ingredients together and give the medicine its shape and size.
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UNII ETJ7Z6XBU4
Silicon dioxide is a naturally occurring mineral used as a glidant and anti-caking agent. It helps powder ingredients flow smoothly and prevents clumping during manufacturing and storage.
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UNII O8232NY3SJ
A plant-based carbohydrate derived from corn kernels. It acts as a filler to add bulk, a binder to hold ingredients together, and a disintegrant to help the tablet break apart in your stomach for absorption.
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UNII 4ELV7Z65AP
Stearic acid is a fatty acid derived from plant or animal sources. It acts as a binder and lubricant in tablets and capsules, helping them hold together and flow smoothly during manufacturing.
6 inactive ingredients listed in the exact product block matched to this NDC.
Where does this data come from?
ingredient classCode="IACT" elements from the exact product block matched by this NDC. Label-section narrative from DailyMed / the openFDA label index is shown separately when available.- FDA label on DailyMed · label index refreshed Oct 8, 2026
- FDA openFDA NDC Directory · synced Oct 8, 2026
Inactive ingredient FAQ
Are inactive ingredients the same for every manufacturer?
Why might an inactive ingredient be missing?
Can inactive ingredients matter?
Manufacturer & labeler
More NDCs from SpecGx LLC labeler code 00406
- Acetaminophen and Codeine Phosphate 300 mg; 30 mg Tablet NDC 0406-0484-01
- Acetaminophen and Codeine Phosphate 300 mg; 60 mg Tablet NDC 0406-0485-01
- Oxycodone and Acetaminophen 5 mg; 325 mg Tablet NDC 0406-0512-01
- Oxycodone and Acetaminophen 7.5 mg; 325 mg Tablet NDC 0406-0522-01
- Oxycodone and Acetaminophen 10 mg; 325 mg Tablet NDC 0406-0523-01
- METHADOSE methadone hydrochloride 10 mg/mL Concentrate NDC 0406-0527-10
- Levorphanol Tartrate 1 g/g Powder NDC 0406-0545-05
- Oxycodone Hydrochloride 5 mg Tablet NDC 0406-0552-01
- Methylphenidate Hydrochloride 1 kg/kg Powder NDC 0406-0570-06
- Sufentanil Citrate 1 g/g Powder NDC 0406-0672-05
- Sufentanil Citrate 1 g/g Powder NDC 0406-0678-05
- Paracetamol 1 kg/kg Powder NDC 0406-0694-35
Where does this data come from?
- FDA openFDA NDC Directory · synced Oct 8, 2026
- Drugs@FDA
Full prescribing information FDA SPL
🚨 Boxed Warning ▾
WARNING: LIFE-THREATENING RESPIRATORY DEPRESSION, LIFE-THREATENING QT PROLONGATION, ACCIDENTAL INGESTION, ABUSE POTENTIAL, INTERACTIONS WITH DRUGS AFFECTING CYTOCHROME P450 ISOENZYMES and TREATMENT FOR OPIOID ADDICTION Life-Threatening Respiratory Depression Respiratory depression, including fatal cases, have been reported during initiation and conversion of patients to methadone, and even when the drug has been used as recommended and not misused or abused [see Warnings and Precautions ( 5.1 )]. Proper dosing and titration are essential and methadone hydrochloride tablets for oral suspension should only be prescribed by healthcare professionals who are knowledgeable in the use of methadone for detoxification and maintenance treatment of opioid addiction.
Monitor for respiratory depression, especially during initiation of methadone hydrochloride tablets for oral suspension or following a dose increase. The peak respiratory depressant effect of methadone occurs later, and persists longer than the peak pharmacologic effect, especially during the initial dosing period. Managing Risks from Concomitant Use with Benzodiazepines or Other CNS Depressants Concomitant use with benzodiazepines or other central nervous system (CNS) depressants, including alcohol, is a risk factor for respiratory depression and death [see Warnings and Precautions ( 5.2 ), Drug Interactions ( 7 )].
Reserve concomitant prescribing of benzodiazepines or other CNS depressants in patients in methadone treatment to those for whom alternatives to benzodiazepines or other CNS depressants are inadequate. Follow patients for signs and symptoms of respiratory depression and sedation. If the patient is visibly sedated, evaluate the cause of sedation and consider delaying or omitting daily methadone dosing.
Life-Threatening QT Prolongation QT interval prolongation and serious arrhythmia ( torsades de pointes ) have occurred during treatment with methadone [see Warnings and Precautions ( 5.3 )]. 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 tablets for oral suspension.
Accidental Ingestion Accidental ingestion of methadone hydrochloride tablets for oral suspension, especially by children, can result in fatal overdose of methadone [see Warnings and Precautions ( 5.4 )]. Misuse, Abuse, and Diversion of Opioids Methadone hydrochloride tablets for oral suspension contain methadone, an opioid agonist and Schedule II controlled substance with an abuse liability similar to other opioid agonists, legal or illicit [see Warnings and Precautions ( 5.5 )]. Interactions with Drugs Affecting Cytochrome P450 Isoenzymes The concomitant use of methadone hydrochloride tablets for oral suspension 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 can result in an increase in methadone levels [see Warnings and Precautions ( 5.7 ), Drug Interactions ( 7 )]. 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, in… [Excerpted — this section continues on DailyMed.]
🎯 Indications and Usage ▾
1 INDICATIONS AND USAGE Methadone hydrochloride tablets for oral suspension contain methadone, an opioid agonist indicated for the: 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 42 CFR 8.12 [see Dosage and Administration ( 2.1 )] .
Methadone hydrochloride tablets for oral suspension are an opioid agonist indicated for the: 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 )
⏱️ Dosage and Administration ▾
2 DOSAGE AND ADMINISTRATION Strongly consider recommending or prescribing an opioid overdose reversal agent (e.g., naloxone, nalmefene) at the time methadone hydrochloride tablets for oral suspension 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.
( 2.5 ) Maintenance Treatment : Clinical stability is most commonly achieved at doses between 80 to 120 mg/day. ( 2.6 ) Do not rapidly reduce or abruptly discontinue methadone hydrochloride tablets for oral suspension in a physically-dependent patient. ( 2.7 , 5.15 )
2.1Conditions 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)).
2.2Important Dosage and Administration Information Methadone hydrochloride tablets for oral suspension are for oral administration only. The preparation must not be injected. 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 hydrochloride tablets for oral suspension have a narrow therapeutic index, especially when combined with other drugs.
2.3Patient 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 ove… [Excerpted — this section continues on DailyMed.]
💊 Dosage Forms and Strengths ▾
3 DOSAGE FORMS AND STRENGTHS METHADOSE ® Dispersible Tablet for oral administration following dispersion in a liquid: 40 mg of methadone hydrochloride and is a white, round, cross-scored dispersible tablet. Methadone Hydrochloride Tablets (dispersible, orange flavored) for oral administration following dispersion in a liquid: 40 mg of methadone hydrochloride and is an orange, rectangular, cross-scored dispersible tablet. Tablets intended for dispersion in a liquid immediately prior to oral administration: 40 mg and 40 mg (orange flavored).
( 3 )
⛔ Contraindications ▾
4 CONTRAINDICATIONS Methadone hydrochloride tablets for oral suspension are 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 tablets for oral suspension [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 )
⚠️ Warnings and Cautions ▾
5 WARNINGS AND PRECAUTIONS Neonatal Opioid Withdrawal Syndrome : Neonatal opioid withdrawal syndrome (NOWS) is an expected and treatable outcome of prolonged use of opioids during pregnancy. ( 5.6 ) Life-Threatening Respiratory Depression in Patients with Chronic Pulmonary Disease or in Elderly, Cachectic, or Debilitated Patients : Monitor closely, particularly during initiation and titration. ( 5.8 ) Serotonin Syndrome : Potentially life-threatening condition could result from concomitant serotonergic drug administration.
Discontinue methadone hydrochloride tablets for oral suspension if serotonin syndrome is suspected. ( 5.9 ) Adrenal Insufficiency : If diagnosed, treat with physiologic replacement of corticosteroids, and wean patient off of the opioid. ( 5.10 ) Severe Hypotension : Monitor during dose initiation and titration.
( 5.11 ) Risks of Use in Patients with Head Injury and Increased Intracranial Pressure : Monitor for sedation and respiratory depression. Avoid use of methadone in patients with impaired consciousness or coma susceptible to intracranial effects of CO 2 retention. ( 5.12 )
5.1Life-Threatening Respiratory Depression Serious, life-threatening, or fatal respiratory depression has been reported with the use of methadone, even when used as recommended. Respiratory depression, if not immediately recognized and treated, may lead to respiratory arrest and death. Respiratory depression from opioids is manifested by a reduced urge to breathe and a decreased rate of respiration, often associated with a “sighing” pattern of breathing (deep breaths separated by abnormally long pauses).
Carbon dioxide (CO 2 ) retention from opioid-induced respiratory depression can exacerbate the sedating effects of opioids. Management of respiratory depression may include close observation, supportive measures, and use of opioid overdose reversal agents , depending on the patient’s clinical status [see Overdosage ( 10 )] . While serious, life-threatening, or fatal respiratory depression can occur at any time during the use of methadone hydrochloride tablets for oral suspension, the risk is greatest during the initiation of therapy or following a dose increase.
The peak respiratory depressant effect of methadone occurs later, and persists longer than the peak pharmacologic effect, especially during the initial dosing period. Monitor patients closely for respiratory depression, when initiating therapy with methadone hydrochloride tablets for oral suspension and following dose increases. Instruct patients against use by individuals other than the patient for whom methadone was prescribed and to keep methadone out of the reach of children, as such inappropriate use may result in fatal respiratory depression [see Patient Counseling Information ( 17 )] .
To reduce the risk of respiratory depression, proper dosing and titration of methadone are essential [see Dosage and Administration ( 2.5 )] . Overestimating the methadone dosage when initiating treatment can result in fatal overdose with the first dose. To further reduce the risk of respiratory depression, consider the following: Patients tolerant to other opioids may be incompletely tolerant to methadone.
Incomplete cross-tolerance is of particular concern for patients tolerant to other mu-opioid agonists. Deaths have been reported during conversion from chronic, high-dose treatment with other opioid agonists. Follow induction directions closely to avoid inadvertent overdose [see Dosage and Administration ( 2.5 )] .
Proper dosing and titration are essential and methadone should be overseen only by healthcare professionals who are knowledgeable in the pharmacokinetics and pharmacodynamics of methadone. Educate patients and caregivers on how to recognize respiratory depression and emphasize the importance of calling 911 or getting emergency medical help right away in the event of a known or suspected overdose [see Patient Counseling Information ( 17 )] . Opioids can cause sleep-related… [Excerpted — this section continues on DailyMed.]
🤒 Adverse Reactions ▾
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 included lightheadedness, dizziness, sedation, nausea, vomiting, and sweating. These effects seemed 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 tablets for oral suspension.
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. Anaphylaxis: Anaphylaxis has been reported with ingredients contained in methadone hydrochloride tablets for oral suspension.
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, dizzine… [Excerpted — this section continues on DailyMed.]
🔄 Drug Interactions ▾
7 DRUG INTERACTIONS Table 1: Clinically Significant Drug Interactions with Methadone Hydrochloride Tablets for Oral Suspension 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: 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: Benzodiazepines and other sedatives/hypnotics, anxiolytics, tranquilizers, muscle relaxants, general anesthetics, antipsychotics, gabapentinoids (gabapentin or pregabalin), other opioids, alcohol. 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 tablets for oral suspension 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 hydrochloride tablets for oral suspension 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 hydrochloride tablets for oral suspension 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 hydrochloride tablets for oral suspension 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 hydrochloride tablets for oral suspension 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 inducer, as the effects of the inducer decline, the methadone plasma concentration can increase [see Clinical Pharmacology ( 12.3 )] , which could increase or prolong both the therapeutic effects and adverse reactions, and… [Excerpted — this section continues on DailyMed.]
👥 Use in Specific Populations ▾
8 USE IN SPECIFIC POPULATIONS Lactation : Monitor breastfed infants for increased drowsiness and breathing difficulties. ( 8.2 )
8.1Pregnancy 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 Precautio ns ( 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 hydrochloride tablets for oral suspension. 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 ( 2.10 ) and 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 hydrochloride tablets for oral suspension. 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 d… [Excerpted — this section continues on DailyMed.]
🤰 Pregnancy ▾
8.1Pregnancy 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 Precautio ns ( 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 hydrochloride tablets for oral suspension. 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 ( 2.10 ) and 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 hydrochloride tablets for oral suspension. 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 for signs of neonatal opioid withdrawal sy… [Excerpted — this section continues on DailyMed.]
🧒 Pediatric Use ▾
8.4Pediatric Use The safety, effectiveness, and pharmacokinetics of methadone in pediatric patients below the age of 18 years have not been established.
🧓 Geriatric Use ▾
8.5Geriatric Use Clinical studies of methadone did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently compared to younger subjects. Other reported clinical experience has not identified differences in responses between elderly and younger patients. In general, start elderly at the low end of the dosing range, taking into account the greater frequency of decreased hepatic, renal, or cardiac function and of concomitant disease or other drug therapy in geriatric patients.
Closely monitor elderly patients for signs of respiratory and central nervous system depression. Methadone is known to be substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.
🆘 Overdosage ▾
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 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 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 reversal would be expected to be less than the duration of action of methadone, carefully monitor the patient until spontaneous respiration is reliably reestablished.
If the response to 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, 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.
🧬 Clinical Pharmacology ▾
12 CLINICAL PHARMACOLOGY
12.1Mechanism of Action Methadone hydrochloride is a mu-agonist; a synthetic opioid 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 methadone withdrawal 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.
12.2Pharmacodynamics Effects on the Central Nervous System Methadone produces respiratory depression by direct action on brain stem respiratory centers. The respiratory depression involves a reduction in the responsiveness of the brain stem respiratory centers to both increases in carbon dioxide tension and electrical stimulation. Methadone causes miosis, even in total darkness.
Pinpoint pupils are a sign of opioid overdose but are not pathognomonic (e.g., pontine lesions of hemorrhagic or ischemic origins may produce similar findings). Marked mydriasis rather than miosis may be seen due to hypoxia in overdose situations. Some NMDA receptor antagonists have been shown to produce neurotoxic effects in animals.
Effects on the Gastrointestinal Tract and Other Smooth Muscle Methadone causes a reduction in motility associated with an increase in smooth muscle tone in the antrum of the stomach and duodenum. Digestion of food in the small intestine is delayed and propulsive contractions are decreased. Propulsive peristaltic waves in the colon are decreased, while tone is increased to the point of spasm, resulting in constipation.
Other opioid-induced effects may include a reduction in biliary and pancreatic secretions, spasm of sphincter of Oddi, transient elevations in serum amylase, and opioid-induced esophageal dysfunction (OIED). Effects on the Cardiovascular System Methadone produces peripheral vasodilation, which may result in orthostatic hypotension or syncope. Manifestations of histamine release and/or peripheral vasodilation may include pruritus, flushing, red eyes, sweating, and/or orthostatic hypotension.
Effects on the Endocrine System Opioids inhibit the secretion of adrenocorticotropic hormone (ACTH), cortisol, and luteinizing hormone (LH) in humans [see Adverse Reactions ( 6 )] . They also stimulate prolactin, growth hormone (GH) secretion, and pancreatic secretion of insulin and glucagon. Chronic use of opioids may influence the hypothalamic-pituitary-gonadal axis, leading to androgen deficiency that may manifest as low libido, impotence, erectile dysfunction, amenorrhea, or infertility.
The causal role of opioids in the clinical syndrome of hypogonadism is unknown because the various medical, physical, lifestyle, and psychological stressors that may influence gonadal hormone levels have not been adequately controlled for in studies conducted to date [see Adverse Reactions ( 6 )] . Effects on the Immune System Opioids have been shown to have a variety of effects on components of the immune system in in vitro and animal models. The clinical significance of these findings is unknown.
Overall, the effects of opioids appear to be modestly immunosuppressive. Concentration-Adverse Reaction Relationships There is a relationship between increasing methadone plasma concentration and increasing frequency of dose-related opioid adverse reactions such as nausea, vomiting, CNS effects, and respiratory depression. In opioid-tolerant patients, the situation may be altered by the development of tolerance to opioid-related adverse reactions [see Dosage and Administration ( 2.5 , 2.6 , 2.7 )] .
12.3Pharmacokinetics Absorption Following oral administration the bioavailability of methadone ranges between 36 to 100% and peak plasma concentrations are achieved between 1 to 7.5 hours. Dose proporti… [Excerpted — this section continues on DailyMed.]
🧬 Mechanism of Action ▾
12.1Mechanism of Action Methadone hydrochloride is a mu-agonist; a synthetic opioid 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 methadone withdrawal 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.
📦 How Supplied / Storage and Handling ▾
16 HOW SUPPLIED/STORAGE AND HANDLING METHADOSE ® Dispersible Tablets, 40 mg: Available as a white, round tablet, debossed with “METHADOSE 40” on one side, a quadrisect on the other. Bottles of 100……NDC 0406-0540-34 Methadone Hydrochloride Tablets for Oral Suspension, USP (Dispersible, Orange Flavored), 40 mg: Available as a speckled orange colored, rounded rectangular tablet, debossed with “M” over “2540” on one side, a quadrisect on the other with an orange odor. Bottles of 100……NDC 0406-2540-01 Methadone hydrochloride tablets for oral suspension, if dispensed, must be packaged in child-resistant containers.
Store at 25°C (77°F); excursions permitted to 15° to 30°C (59° to 86°F) [see USP Controlled Room Temperature]. Store methadone hydrochloride tablets for oral suspension securely and dispose of properly [see Patient Counseling Information ( 17 )] .
📋 Description ▾
11 DESCRIPTION Methadone hydrochloride tablets for oral suspension contain methadone, an opioid agonist, available as 40 mg dispersible tablets for oral administration. Methadone hydrochloride is chemically described as 6-(dimethylamino)-4,4-diphenyl-3-heptanone 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 tablets for oral suspension 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 molecular formula is C 21 H 27 NO•HCl and its structural formula is: Each METHADOSE ® Dispersible Tablet (methadone hydrochloride tablets for oral suspension USP) contains 40 mg of methadone hydrochloride USP and the following inactive ingredients: dibasic calcium phosphate, microcrystalline cellulose, magnesium stearate, colloidal silicon dioxide, pregelatinized starch, stearic acid. Each Methadone Hydrochloride Tablet (methadone hydrochloride tablets for oral suspension USP) (dispersible, orange flavored) contains 40 mg of methadone hydrochloride USP and the following inactive ingredients: colloidal silicon dioxide; monobasic potassium phosphate; magnesium stearate; microcrystalline cellulose; pregelatinized starch; stearic acid; orange blend: FD&C yellow #6, FD&C yellow #6 lake, and FD&C yellow #5 lake; orange flavor.
Methadone hydrochloride tablets for oral suspension are cross-scored, allowing for flexible dosage adjustment. Each tablet may be broken or cut in half to yield two 20-mg doses, or in quarters to yield four 10-mg doses. Methadone hydrochloride tablets for oral suspension are for oral administration following dispersion in a liquid.
Methadone hydrochloride tablets for oral suspension contain insoluble excipients and must not be injected. Chemical Structure
🧬 Pharmacokinetics ▾
12.3Pharmacokinetics Absorption Following oral administration the bioavailability of methadone ranges between 36 to 100% and peak plasma concentrations are achieved between 1 to 7.5 hours. Dose proportionality of methadone pharmacokinetics is not known. However, after administration of daily oral doses ranging from 10 to 225 mg, the steady-state plasma concentrations ranged between 65 to 630 ng/mL and the peak concentrations ranged between 124 to 1,255 ng/mL.
Effect of food on the bioavailability of methadone has not been evaluated. Distribution Methadone is a lipophilic drug and the steady-state volume of distribution ranges between 1 to 8 L/kg. In plasma, methadone is predominantly bound to α1-acid glycoprotein (85% to 90%).
Methadone is secreted in saliva, breast milk, amniotic fluid and umbilical cord plasma. Elimination Metabolism : Methadone is primarily metabolized by N-demethylation to an inactive metabolite, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidene(EDDP). Cytochrome P450 enzymes, primarily CYP3A4, CYP2B6, CYP2C19, CYP2C9 and CYP2D6, are responsible for conversion of methadone to EDDP and other inactive metabolites, which are excreted mainly in the urine.
Methadone appears to be a substrate for P-glycoprotein but its pharmacokinetics do not appear to be significantly altered in case of P-glycoprotein polymorphism or inhibition. Excretion : The elimination of methadone is mediated by extensive biotransformation, followed by renal and fecal excretion. Published reports indicate that after multiple dose administration the apparent plasma clearance of methadone ranged between 1.4 and 126 L/h, and the terminal half-life (T 1/2 ) was highly variable and ranged between 8 to 59 hours in different studies.
Methadone is a basic (pKa=9.2) compound and the pH of the urinary tract can alter its disposition in plasma. Also, since methadone is lipophilic, it has been known to persist in the liver and other tissues. The slow release from the liver and other tissues may prolong the duration of methadone action despite low plasma concentrations.
Drug Interaction Studies Cytochrome P450 Interactions : Methadone undergoes hepatic N-demethylation by cytochrome P450 (CYP) isoforms, principally CYP3A4, CYP2B6, CYP2C19, CYP2C9, and CYP2D6. Co-administration of methadone with CYP inducers may result in more rapid metabolism and potential for decreased effects of methadone, whereas administration with CYP inhibitors may reduce metabolism and potentiate methadone’s effects. Although antiretroviral drugs such as efavirenz, nelfinavir, nevirapine, ritonavir, lopinavir+ritonavir combination are known to inhibit some CYPs, they are shown to reduce the plasma levels of methadone, possibly due to CYP induction activity [see Drug Interactions ( 7 )] .
Cytochrome P450 Inducers : The following drug interactions were reported following co-administration of methadone with known inducers of cytochrome P450 enzymes: Rifampin : In patients well-stabilized on methadone, concomitant administration of rifampin resulted in a marked reduction in serum methadone levels and a concurrent appearance of withdrawal symptoms. Phenytoin : In a pharmacokinetic study with patients on methadone maintenance therapy, phenytoin administration (250 mg twice daily initially for 1 day followed by 300 mg daily for 3 to 4 days) resulted in an approximately 50% reduction in methadone exposure and withdrawal symptoms occurred concurrently.
Upon discontinuation of phenytoin, the incidence of withdrawal symptoms decreased and methadone exposure increased to a level comparable to that prior to phenytoin administration. St. John’s Wort, Phenobarbital, Carbamazepine : Administration of methadone with other CYP3A4 inducers may result in withdrawal symptoms.
Cytochrome P450 Inhibitors: Voriconazole : Voriconazole can inhibit the activity of CYP3A4, CYP2C9, and CYP2C19. Repeat dose administration of oral voriconazole (400 mg every 12 hours for 1 day, then 200 mg every 12 hours for 4… [Excerpted — this section continues on DailyMed.]
🧬 Pharmacodynamics ▾
12.2Pharmacodynamics Effects on the Central Nervous System Methadone produces respiratory depression by direct action on brain stem respiratory centers. The respiratory depression involves a reduction in the responsiveness of the brain stem respiratory centers to both increases in carbon dioxide tension and electrical stimulation. Methadone causes miosis, even in total darkness.
Pinpoint pupils are a sign of opioid overdose but are not pathognomonic (e.g., pontine lesions of hemorrhagic or ischemic origins may produce similar findings). Marked mydriasis rather than miosis may be seen due to hypoxia in overdose situations. Some NMDA receptor antagonists have been shown to produce neurotoxic effects in animals.
Effects on the Gastrointestinal Tract and Other Smooth Muscle Methadone causes a reduction in motility associated with an increase in smooth muscle tone in the antrum of the stomach and duodenum. Digestion of food in the small intestine is delayed and propulsive contractions are decreased. Propulsive peristaltic waves in the colon are decreased, while tone is increased to the point of spasm, resulting in constipation.
Other opioid-induced effects may include a reduction in biliary and pancreatic secretions, spasm of sphincter of Oddi, transient elevations in serum amylase, and opioid-induced esophageal dysfunction (OIED). Effects on the Cardiovascular System Methadone produces peripheral vasodilation, which may result in orthostatic hypotension or syncope. Manifestations of histamine release and/or peripheral vasodilation may include pruritus, flushing, red eyes, sweating, and/or orthostatic hypotension.
Effects on the Endocrine System Opioids inhibit the secretion of adrenocorticotropic hormone (ACTH), cortisol, and luteinizing hormone (LH) in humans [see Adverse Reactions ( 6 )] . They also stimulate prolactin, growth hormone (GH) secretion, and pancreatic secretion of insulin and glucagon. Chronic use of opioids may influence the hypothalamic-pituitary-gonadal axis, leading to androgen deficiency that may manifest as low libido, impotence, erectile dysfunction, amenorrhea, or infertility.
The causal role of opioids in the clinical syndrome of hypogonadism is unknown because the various medical, physical, lifestyle, and psychological stressors that may influence gonadal hormone levels have not been adequately controlled for in studies conducted to date [see Adverse Reactions ( 6 )] . Effects on the Immune System Opioids have been shown to have a variety of effects on components of the immune system in in vitro and animal models. The clinical significance of these findings is unknown.
Overall, the effects of opioids appear to be modestly immunosuppressive. Concentration-Adverse Reaction Relationships There is a relationship between increasing methadone plasma concentration and increasing frequency of dose-related opioid adverse reactions such as nausea, vomiting, CNS effects, and respiratory depression. In opioid-tolerant patients, the situation may be altered by the development of tolerance to opioid-related adverse reactions [see Dosage and Administration ( 2.5 , 2.6 , 2.7 )] .
🔒 Drug Abuse and Dependence ▾
9 DRUG ABUSE AND DEPENDENCE
9.1Controlled Substance Methadone hydrochloride tablets for oral suspension contain methadone, a Schedule II controlled substance.
9.2Abuse Methadone hydrochloride tablets for oral suspension contain methadone, a substance with a high potential for abuse similar to other opioids including fentanyl, hydrocodone, hydromorphone, morphine, oxycodone, oxymorphone, and tapentadol. Methadone hydrochloride tablets for oral suspension can be abused and is subject to misuse, addiction, and criminal diversion [see Warnings and Precautions ( 5.5 )] . Prescription drug abuse is the intentional non-therapeutic use of a prescription drug, even once, for its rewarding psychological or physiological effects.
Drug addiction is a cluster of behavioral, cognitive, and physiological phenomena that develop after repeated substance use and includes: a strong desire to take the drug, difficulties in controlling its use, persisting in its use despite harmful consequences, a higher priority given to drug use than to other activities and obligations, increased tolerance, and sometimes a physical withdrawal. “Drug-seeking” behavior is very common in persons with substance use disorders. Drug-seeking tactics include emergency calls or visits near the end of office hours, refusal to undergo appropriate examination, testing or referral, repeated “loss” of prescriptions, tampering with prescriptions, and reluctance to provide prior medical records or contact information for other treating healthcare provider(s). “Doctor shopping” (visiting multiple prescribers to obtain additional prescriptions) is common among drug abusers and people suffering from untreated addiction.
Abuse and addiction are separate and distinct from physical dependence and tolerance. Healthcare providers should be aware that addiction may not be accompanied by concurrent tolerance and symptoms of physical dependence in all addicts. In addition, abuse of opioids can occur in the absence of true addiction.
Methadone hydrochloride tablets for oral suspension, like other opioids, can be diverted for non-medical use into illicit channels of distribution. Careful record-keeping of prescribing information, including quantity and frequency as required by state and federal law, is strongly advised. Proper assessment and selection of the patient, proper prescribing practices, periodic re-evaluation of therapy, and proper dispensing and storage are appropriate measures that help to limit abuse of opioid drugs.
Risks Specific to Methadone Hydrochloride Tablets for Oral Suspension Abuse of methadone poses a risk of overdose and death. This risk is increased with concurrent abuse of methadone with alcohol and other substances. Methadone hydrochloride tablets for oral suspension are intended for oral use only and must not be injected.
Parenteral drug abuse is commonly associated with transmission of infectious diseases such as hepatitis and HIV. Methadone hydrochloride tablets for oral suspension, when used for the treatment of opioid addiction in detoxification or maintenance programs, may be dispensed only by opioid treatment programs certified by the Substance Abuse and Mental Health Services Administration (and agencies, practitioners, and institutions by formal agreements with the program sponsor).
9.3Dependence Both tolerance and physical dependence can develop during chronic opioid therapy. Tolerance is the need for increasing doses of opioids to maintain a defined effect (in the absence of disease progression or other external factors). Tolerance may occur to both the desired and undesired effects of drugs and may develop at different rates for different effects.
Physical dependence results in withdrawal symptoms after abrupt discontinuation or significant dose reduction of a drug. Withdrawal is also precipitated through the administration of drugs with opioid antagonist activity (e.g., naloxone, nalmefene) or mixed agonist/antagonist analgesics (e.g., pentazocine… [Excerpted — this section continues on DailyMed.]
🔒 Controlled Substance ▾
9.1Controlled Substance Methadone hydrochloride tablets for oral suspension contain methadone, a Schedule II controlled substance.
🧪 Nonclinical Toxicology ▾
13 NONCLINICAL TOXICOLOGY
13.1Carcinogenesis, Mutagenesis, Impairment of Fertility Carcinogenesis The results of carcinogenicity assessment in B6C2F1 mice and Fischer 344 rats following dietary administration of two doses of methadone HCl have been published. Mice consumed 15 mg/kg/day or 60 mg/kg/day methadone for two years. These doses were approximately 0.6 and 2.5 times a human daily oral dose of 120 mg/day on a body surface area basis (HDD).
There was a significant increase in pituitary adenomas in female mice treated with 15 mg/kg/day but not with 60 mg/kg/day. Under the conditions of the assay, there was no clear evidence for a treatment-related increase in the incidence of neoplasms in male rats. Due to decreased food consumption in males at the high dose, male rats consumed 16 mg/kg/day and 28 mg/kg/day of methadone for two years.
These doses were approximately 1.3 and 2.3 times the HDD. In contrast, female rats consumed 46 mg/kg/day or 88 mg/kg/day for two years. These doses were approximately 3.7 and 7.1 times the HDD.
Under the conditions of the assay, there was no clear evidence for a treatment-related increase in the incidence of neoplasms in either male or female rats. Mutagenesis There are several published reports on the potential genetic toxicity of methadone. Methadone tested positive in the in vivo mouse dominant lethal assay and the in vivo mammalian spermatogonial chromosome aberration test.
Additionally, methadone tested positive in the E. coli DNA repair system and Neurospora crassa and mouse lymphoma forward mutation assays. In contrast, methadone tested negative in tests for chromosome breakage and disjunction and sex-linked recessive lethal gene mutations in germ cells of Drosophila using feeding and injection procedures. Fertility Published animal studies show that methadone treatment of males can alter reproductive function.
Methadone produces decreased sexual activity (mating) of male rats at 10 mg/kg/day (corresponding to 0.3 times the human daily oral dose of 120 mg/day based on body surface area). Methadone also produces a significant regression of sex accessory organs and testes of male mice and rats at 0.2 and 0.8 times the HDD, respectively. Methadone treatment of pregnant rats from Gestation Day 14 to 19 reduced fetal blood testosterone and androstenedione in males.
Decreased serum levels of testosterone were observed in male rats that were treated with methadone (1.3 to 3.3 mg/kg/day for 14 days, corresponding to 0.1 to 0.3 times the HDD) or 10 to 15 mg/kg/day for 10 days (0.8 to 1.2 times the HDD).
📄 Carcinogenesis, Mutagenesis, Impairment of Fertility ▾
13.1Carcinogenesis, Mutagenesis, Impairment of Fertility Carcinogenesis The results of carcinogenicity assessment in B6C2F1 mice and Fischer 344 rats following dietary administration of two doses of methadone HCl have been published. Mice consumed 15 mg/kg/day or 60 mg/kg/day methadone for two years. These doses were approximately 0.6 and 2.5 times a human daily oral dose of 120 mg/day on a body surface area basis (HDD).
There was a significant increase in pituitary adenomas in female mice treated with 15 mg/kg/day but not with 60 mg/kg/day. Under the conditions of the assay, there was no clear evidence for a treatment-related increase in the incidence of neoplasms in male rats. Due to decreased food consumption in males at the high dose, male rats consumed 16 mg/kg/day and 28 mg/kg/day of methadone for two years.
These doses were approximately 1.3 and 2.3 times the HDD. In contrast, female rats consumed 46 mg/kg/day or 88 mg/kg/day for two years. These doses were approximately 3.7 and 7.1 times the HDD.
Under the conditions of the assay, there was no clear evidence for a treatment-related increase in the incidence of neoplasms in either male or female rats. Mutagenesis There are several published reports on the potential genetic toxicity of methadone. Methadone tested positive in the in vivo mouse dominant lethal assay and the in vivo mammalian spermatogonial chromosome aberration test.
Additionally, methadone tested positive in the E. coli DNA repair system and Neurospora crassa and mouse lymphoma forward mutation assays. In contrast, methadone tested negative in tests for chromosome breakage and disjunction and sex-linked recessive lethal gene mutations in germ cells of Drosophila using feeding and injection procedures. Fertility Published animal studies show that methadone treatment of males can alter reproductive function.
Methadone produces decreased sexual activity (mating) of male rats at 10 mg/kg/day (corresponding to 0.3 times the human daily oral dose of 120 mg/day based on body surface area). Methadone also produces a significant regression of sex accessory organs and testes of male mice and rats at 0.2 and 0.8 times the HDD, respectively. Methadone treatment of pregnant rats from Gestation Day 14 to 19 reduced fetal blood testosterone and androstenedione in males.
Decreased serum levels of testosterone were observed in male rats that were treated with methadone (1.3 to 3.3 mg/kg/day for 14 days, corresponding to 0.1 to 0.3 times the HDD) or 10 to 15 mg/kg/day for 10 days (0.8 to 1.2 times the HDD).
📄 Recent Major Changes ▾
Warnings and Precautions ( 5.17 ) 12/2023 Dosage and Administration ( 2.3 , 2.7 ) 12/2025 Warnings and Precautions ( 5.1 , 5.2 , 5.13 , 5.15 ) 12/2025
📄 Package Label / Principal Display Panel ▾
PRINCIPAL DISPLAY PANEL - METHADOSE NDC 0406- 0540 -34 100 TABLETS METHADOSE ® Dispersible Tablets (Methadone Hydrochloride Tablets for Oral Suspension USP) CII 40 mg Each tablet contains: Methadone Hydrochloride USP. . . . . . . 40 mg Rx only Par Health™ L00M10 Rev 01/2026 PRINCIPAL DISPLAY PANEL - 40 mg Bottle Label
PRINCIPAL DISPLAY PANEL - METHADONE HYDROCHLORIDE TABLETS NDC 0406- 2540 -01 100 TABLETS METHADONE HYDROCHLORIDE TABLETS (Methadone Hydrochloride Tablets for Oral Suspension USP) 40 mg CII (Dispersible, Orange Flavored) Each tablet contains: Methadone Hydrochloride USP. . . . . . . 40 mg Rx only Par Health™ L00M82 Rev 01/2026 40 mg orange
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