Methadone (Injection route)

Pronunciation:

METH-a-done

Dosage Forms:

Solution

Warnings:

Injection route(Solution)

Addiction, Abuse, and MisuseBecause 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.Life-Threatening Respiratory DepressionSerious, 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.Neonatal Opioid Withdrawal Syndrome (NOWS)If opioid use is required for an extended period of time in a pregnant woman, advise the patient of the risk of NOWS, which may be life-threatening if not recognized and treated. Ensure that management by neonatology experts will be available at delivery.Risks from Concomitant Use with Benzodiazepines or Other CNS DepressantsConcomitant 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 in methadone treatment for whom alternative treatment options are inadequate.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.Interactions with Drugs Affecting Cytochrome P450 IsoenzymesThe concomitant use of methadone hydrochloride 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.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 .

Classifications:

Therapeutic—

Analgesic

Chemical—

Opioid

Uses of This Medicine:

Methadone injection is used to relieve severe and persistent pain that requires daily opioid treatment and when other pain medicines did not work well enough or cannot be tolerated. This medicine should not be used to treat pain that you only have once in a while or "as needed". Methadone injection is also used together with medical supervision and counseling to treat opioid addiction (eg, heroin or other morphine-like drugs) in patients who cannot take oral medicines.

Methadone is an opioid analgesic (pain medicine). It acts on the nervous system to relieve pain.

This medicine is to be given only by or under the direct supervision of a doctor.

Before Using This Medicine:

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies—

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Children—

Appropriate studies have not been performed on the relationship of age to the effects of methadone injection in the pediatric population. Safety and efficacy have not been established.

Older adults—

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of methadone injection in the elderly. However, elderly patients are more likely to have age-related heart, kidney, liver, or lung problems, which may require caution and an adjustment in the dose for patients receiving methadone injection.

Breast-feeding—

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Other medicines—

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are receiving this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

Bepridil
Cisapride
Dronedarone
Fluconazole
Itraconazole
Ketoconazole
Levoketoconazole
Mesoridazine
Naltrexone
Pimozide
Piperaquine
Posaconazole
Rasagiline
Safinamide
Samidorphan
Saquinavir
Sparfloxacin
Terfenadine
Thioridazine
Ziprasidone

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Abacavir
Abametapir
Abiraterone Acetate
Abiraterone Acetate, Micronized
Acepromazine
Aclidinium
Adagrasib
Aldosterone
Alfentanil
Alfuzosin
Almotriptan
Alprazolam
Amantadine
Amiloride
Amineptine
Amiodarone
Amisulpride
Amitriptyline
Amitriptylinoxide
Amobarbital
Amoxapine
Amphetamine
Amprenavir
Anagrelide
Anileridine
Apalutamide
Apomorphine
Aprepitant
Aripiprazole
Aripiprazole Lauroxil
Armodafinil
Arsenic Trioxide
Artemether
Asenapine
Astemizole
Atazanavir
Atropine
Avacopan
Azithromycin
Baclofen
Bedaquiline
Belladonna
Belzutifan
Bemetizide
Bendroflumethiazide
Benperidol
Bentazepam
Benzhydrocodone
Benzphetamine
Benzthiazide
Benztropine
Berotralstat
Biperiden
Boceprevir
Bosentan
Bromazepam
Bromopride
Brompheniramine
Bumetanide
Buprenorphine
Bupropion
Buserelin
Buspirone
Butabarbital
Butalbital
Butorphanol
Calcium Oxybate
Cannabidiol
Cannabis
Canrenoate
Canrenone
Capecitabine
Carbamazepine
Carbidopa
Carbinoxamine
Cariprazine
Carisoprodol
Carphenazine
Cenobamate
Ceritinib
Cetirizine
Chloral Hydrate
Chlordiazepoxide
Chloroquine
Chlorothiazide
Chlorpheniramine
Chlorpromazine
Chlorthalidone
Chlorzoxazone
Cilostazol
Cimetidine
Cinacalcet
Ciprofloxacin
Citalopram
Clarithromycin
Clemastine
Clidinium
Clobazam
Clofazimine
Clomipramine
Clonazepam
Clopamide
Clopidogrel
Clorazepate
Clothiapine
Cloxazolam
Clozapine
Cobicistat
Cocaine
Codeine
Conivaptan
Crizotinib
Cyclobenzaprine
Cyclopenthiazide
Cyclopentolate
Cyclosporine
Cyclothiazide
Cyproheptadine
Dabrafenib
Dantrolene
Daridorexant
Darifenacin
Darunavir
Dasatinib
Degarelix
Delamanid
Delavirdine
Delorazepam
Desflurane
Desipramine
Deslorelin
Desmopressin
Desvenlafaxine
Deutetrabenazine
Deutivacaftor
Dexamethasone
Dexmedetomidine
Dextroamphetamine
Dextromethorphan
Dezocine
Diacetylmorphine
Diazepam
Diazoxide
Dibenzepin
Dichloralphenazone
Dicloxacillin
Dicyclomine
Didanosine
Difenoxin
Dihydrocodeine
Diltiazem
Dimenhydrinate
Diphenhydramine
Diphenoxylate
Dipyrone
Disopyramide
Disulfiram
Dofetilide
Dolasetron
Domperidone
Donepezil
Doxepin
Doxylamine
Droperidol
Duloxetine
Duvelisib
Ebastine
Efavirenz
Elagolix
Eletriptan
Eliglustat
Encorafenib
Enflurane
Entrectinib
Enzalutamide
Eplerenone
Eribulin
Erythromycin
Escitalopram
Esketamine
Eslicarbazepine Acetate
Esomeprazole
Estazolam
Eszopiclone
Ethacrynic Acid
Ethchlorvynol
Ethopropazine
Ethylmorphine
Etozolin
Etrasimod
Famotidine
Fedratinib
Felbamate
Fenfluramine
Fentanyl
Fesoterodine
Fexinidazole
Fingolimod
Flavoxate
Flecainide
Flibanserin
Fludrocortisone
Flunitrazepam
Fluoxetine
Fluphenazine
Flurazepam
Fluspirilene
Fluvoxamine
Formoterol
Fosamprenavir
Fosaprepitant
Foscarbidopa
Foscarnet
Foslevodopa
Fosnetupitant
Fosphenytoin
Fospropofol
Fostemsavir
Frovatriptan
Furosemide
Gabapentin
Gabapentin Enacarbil
Galantamine
Gatifloxacin
Gemifloxacin
Gepirone
Givinostat
Glasdegib
Glycopyrrolate
Glycopyrronium Tosylate
Gonadorelin
Goserelin
Granisetron
Halazepam
Halofantrine
Haloperidol
Halothane
Hexobarbital
Histrelin
Homatropine
Hydrochlorothiazide
Hydrocodone
Hydroflumethiazide
Hydromorphone
Hydroquinidine
Hydroxyamphetamine
Hydroxychloroquine
Hydroxytryptophan
Hydroxyzine
Hyoscyamine
Ibutilide
Idelalisib
Iloperidone
Imatinib
Imipramine
Indapamide
Indinavir
Inotuzumab Ozogamicin
Ipratropium
Isavuconazole
Isocarboxazid
Isoflurane
Ivabradine
Ivacaftor
Ivosidenib
Ketamine
Ketazolam
Ketobemidone
Lacosamide
Lapatinib
Larotrectinib
Lasmiditan
Ledipasvir
Lefamulin
Lemborexant
Lenacapavir
Lenvatinib
Lesinurad
Letermovir
Leuprolide
Levocetirizine
Levodopa
Levofloxacin
Levomilnacipran
Levorphanol
Linezolid
Lisdexamfetamine
Lithium
Lofepramine
Lofexidine
Lomitapide
Lonafarnib
Lopinavir
Loprazolam
Lorazepam
Lorcaserin
Lorlatinib
Lormetazepam
Loxapine
Lumacaftor
Lumefantrine
Lurasidone
Macimorelin
Magnesium Oxybate
Maribavir
Mavacamten
Mavorixafor
Meclizine
Medazepam
Mefloquine
Melitracen
Melperone
Mepenzolate
Meperidine
Mephobarbital
Meprobamate
Meptazinol
Metaclazepam
Metaxalone
Methamphetamine
Methdilazine
Methocarbamol
Methohexital
Methotrimeprazine
Methyclothiazide
Methylene Blue
Methylprednisolone
Metoclopramide
Metolazone
Metronidazole
Miconazole
Midazolam
Mifepristone
Milnacipran
Mirtazapine
Mitotane
Mizolastine
Mobocertinib
Moclobemide
Modafinil
Molindone
Moricizine
Morphine
Morphine Sulfate Liposome
Moxifloxacin
Nafarelin
Nafcillin
Nalbuphine
Naratriptan
Nefazodone
Nelfinavir
Netupitant
Nevirapine
Nicomorphine
Nilotinib
Nirmatrelvir
Nitisinone
Nitrazepam
Nitrous Oxide
Nordazepam
Norfloxacin
Nortriptyline
Octreotide
Ofloxacin
Olanzapine
Oliceridine
Omaveloxolone
Omeprazole
Ondansetron
Opipramol
Opium
Opium Alkaloids
Orphenadrine
Osilodrostat
Osimertinib
Oxaliplatin
Oxandrolone
Oxazepam
Oxcarbazepine
Oxitropium Bromide
Oxybutynin
Oxycodone
Oxymorphone
Ozanimod
Pacritinib
Palbociclib
Paliperidone
Palonosetron
Panobinostat
Papaveretum
Papaverine
Paregoric
Paritaprevir
Paroxetine
Pasireotide
Pazopanib
Peginterferon Alfa-2b
Pentamidine
Pentazocine
Pentobarbital
Perampanel
Perazine
Periciazine
Perphenazine
Phenelzine
Phenobarbital
Phenylbutazone
Phenytoin
Pimavanserin
Pinazepam
Pipamperone
Pipenzolate Bromide
Piperacetazine
Pipotiazine
Pirenzepine
Piretanide
Piritramide
Pitolisant
Polythiazide
Ponesimod
Potassium Oxybate
Prasugrel
Prazepam
Prednisone
Pregabalin
Primidone
Probucol
Procainamide
Procarbazine
Prochlorperazine
Procyclidine
Promazine
Promethazine
Propafenone
Propantheline
Propiverine
Propofol
Protriptyline
Quazepam
Quetiapine
Quinethazone
Quinidine
Quinine
Quizartinib
Ramelteon
Ranitidine
Ranolazine
Regorafenib
Relugolix
Remifentanil
Remimazolam
Remoxipride
Revumenib
Ribociclib
Rifabutin
Rifampin
Rifapentine
Rilpivirine
Risperidone
Ritlecitinib
Ritonavir
Rizatriptan
Rolapitant
Ropeginterferon Alfa-2b-njft
Schisandra sphenanthera
Scopolamine
Secobarbital
Selegiline
Selpercatinib
Sertindole
Sertraline
Sevoflurane
Sibutramine
Siponimod
Sodium Oxybate
Sodium Phosphate
Sodium Phosphate, Dibasic
Sodium Phosphate, Monobasic
Sofosbuvir
Solifenacin
Sorafenib
Sotalol
Sparsentan
Spironolactone
Stiripentol
St John's Wort
Stramonium
Sufentanil
Sulfaphenazole
Sulpiride
Sultopride
Sumatriptan
Sunitinib
Suvorexant
Tacrolimus
Tamoxifen
Tapentadol
Tazemetostat
Telaprevir
Telavancin
Telithromycin
Telotristat Ethyl
Temazepam
Tenofovir Disoproxil Fumarate
Terbinafine
Terodiline
Tetrabenazine
Tetrazepam
Thiethylperazine
Thiopental
Thiopropazate
Thiotepa
Thiothixene
Tianeptine
Ticagrelor
Ticlopidine
Tilidine
Tiotropium
Tipranavir
Tizanidine
Tolonium Chloride
Tolterodine
Topiramate
Toremifene
Torsemide
Tramadol
Tranylcypromine
Trazodone
Triamterene
Triazolam
Trichlormethiazide
Triclabendazole
Trifluoperazine
Trifluperidol
Triflupromazine
Trihexyphenidyl
Trimeprazine
Trimipramine
Triptorelin
Trofinetide
Troleandomycin
Tropicamide
Trospium
Tryptophan
Tucatinib
Umeclidinium
Valproic Acid
Vandetanib
Vardenafil
Vemurafenib
Venlafaxine
Verapamil
Vilanterol
Vilazodone
Vinflunine
Voclosporin
Vonoprazan
Voriconazole
Vorinostat
Vortioxetine
Voxelotor
Xipamide
Zaleplon
Zolmitriptan
Zolpidem
Zopiclone
Zotepine
Zuclopenthixol
Zuranolone

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Etravirine
Peginterferon Alfa-2a
Stavudine
Zidovudine

Other interactions—

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following is usually not recommended, but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco.

Ethanol
Grapefruit Juice

Using this medicine with any of the following may cause an increased risk of certain side effects but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco.

Other medical problems—

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

Alcohol use disorder, or history of or
Brain tumor or
Breathing or lung problems (eg, COPD, cor pulmonale, hypercapnia, hypoxia, apnea, sleep apnea) or
Depression, history of or
Drug dependence, especially opioid use disorder or dependence, history of or
Gallbladder disease or
Head injuries, history of or
Heart disease (eg, cardiac hypertrophy) or
Heart rhythm problems (eg, arrhythmia, long QT syndrome), or history of or
Hypokalemia (low potassium in the blood) or
Hypomagnesemia (low magnesium in the blood) or
Increased pressure in your head or
Stomach or bowel problems or
Weakened physical condition—Use with caution. May increase risk for more serious side effects.

Asthma, acute or severe or
Respiratory depression (serious breathing problem) or
Stomach or bowel blockage (including paralytic ileus), known or suspected—Should not be used in patients with these conditions.

Hypotension (low blood pressure) or
Pancreatitis (inflammation of the pancreas) or
Seizures, history of—Use with caution. May make these conditions worse.

Kidney disease or
Liver disease—Use with caution. The effects may be increased because of slower removal of the medicine from the body.

Proper Use of This Medicine:

A doctor or other trained health professional will give you this medicine in a medical facility. This medicine is given as a shot under your skin or into a muscle or a vein.

Precautions While Using This Medicine:

It is very important that your doctor check your progress while you are using this medicine. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to receive it.

Do not use this medicine if you are using or have used an MAO inhibitor within the past 14 days.

This medicine may cause serious allergic reactions, including anaphylaxis, which can be life-threatening and require immediate medical attention. Call your doctor right away if you have a rash, itching, trouble breathing, trouble swallowing, or any swelling of your hands, face, or mouth while you are using this medicine.

This medicine will add to the effects of alcohol and other central nervous system (CNS) depressants. CNS depressants are medicines that slow down the nervous system, which may cause drowsiness or make you less alert. Some examples of CNS depressants are antihistamines or medicine for allergies or colds, sedatives, tranquilizers, or sleeping medicine, other prescription pain medicine or opioids, medicine for anxiety or benzodiazepines, medicine for seizures or barbiturates, muscle relaxants, or anesthetics (numbing medicines), including some dental anesthetics. This effect may last for a few days after you stop using this medicine. Check with your doctor before taking any of the other medicines listed above while you are using this medicine.

Do not use more of this medicine or use it more often than your doctor tells you to. This can be life-threatening. Symptoms of an overdose include extreme dizziness or weakness, trouble breathing, slow heartbeat, seizures, and cold, clammy skin. Call your doctor right away if you notice these symptoms. Your doctor may also give naloxone to treat an overdose. Naloxone is a medicine that temporarily reverses the effects of an overdose. If you have been prescribed naloxone, make sure household members know how to use this on you in the event of an overdose or suspected overdose. Emergency medical attention is still needed after naloxone is used because the reversal effects are only temporary.

This medicine may cause sleep-related breathing problems (eg, sleep apnea, sleep-related hypoxemia). Your doctor may decrease your dose if you have sleep apnea (stop breathing for short periods during sleep) while using this medicine.

Contact your doctor right away if you have any changes to your heart rhythm. You might feel dizzy or faint, or you might have a fast, pounding, or uneven heartbeat. Make sure your doctor knows if you or anyone in your family has ever had a heart rhythm problem such as QT prolongation.

Using this medicine while you are pregnant may cause neonatal withdrawal syndrome in your newborn child. Tell your doctor right away if your baby has an abnormal sleep pattern, diarrhea, a high-pitched cry, irritability, shakiness or tremors, weight loss, vomiting, or fails to gain weight.

Call your doctor right away if you have worsening of pain, increased sensitivity to pain, or new pain after taking this medicine. These may be symptoms of opioid-induced hyperalgesia and allodynia.

Check with your doctor right away if you have anxiety, restlessness, a fast heartbeat, fever, sweating, muscle spasms, twitching, nausea, vomiting, diarrhea, or see or hear things that are not there. These may be symptoms of a serious condition called serotonin syndrome. Your risk may be higher if you also take certain other medicines that affect serotonin levels in your body.

This medicine may cause adrenal gland problems. Check with your doctor right away if you have darkening of the skin, diarrhea, dizziness, fainting, loss of appetite, mental depression, nausea, skin rash, unusual tiredness or weakness, or vomiting.

This medicine may be habit-forming (causing mental or physical dependence). If you feel that the medicine is not working as well, do not use more than your prescribed dose. Call your doctor for instructions.

Using opioids for a long time can cause severe constipation. To prevent this, your doctor may direct you to take laxatives, drink a lot of fluids, or increase the amount of fiber in your diet. Be sure to follow the directions carefully, because continuing constipation can lead to more serious problems.

If you have been using this medicine regularly for several weeks or more, do not suddenly stop using it without first checking with your doctor. You may be directed to gradually reduce the amount you are using before stopping treatment completely, or to take another opioid for a while, to lessen the chance of withdrawal symptoms.

If you are pregnant and have been on a stable dose of methadone, do not stop taking it without talking to your doctor. Stopping it suddenly may cause withdrawal symptoms and lead to pregnancy complications.

Dizziness, lightheadedness, or fainting may occur when you get up suddenly from a lying or sitting position. Getting up slowly may help lessen this problem. Also, lying down for a while may relieve dizziness or lightheadedness.

This medicine may make you dizzy, drowsy, or lightheaded. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous until you know how this medicine affects you.

Before you have any medical tests, tell the medical doctor in charge that you are using this medicine. The results of some tests may be affected by this medicine.

Using too much of this medicine may cause infertility (unable to have children). Talk with your doctor before using this medicine if you plan to have children.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal (eg, St. John's wort) or vitamin supplements.

Side Effects of This Medicine:

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur:

Incidence not known: Agitation; blurred vision; confusion; darkening of the skin; diarrhea; difficult or troubled breathing; dizziness; dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position; fainting; fever; increased sensitivity to pain; irregular heartbeat; recurrent irregular, fast or slow, or shallow breathing; loss of appetite; mental depression; nausea; overactive reflexes; pale or blue lips, fingernails, or skin; poor coordination; restlessness; seizures; shivering; skin rash; sweating; talking or acting with excitement you cannot control; trembling or shaking; twitching; unusual tiredness or weakness; vomiting; worsening of pain

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Incidence not known: Bleeding, blistering, burning, coldness, discoloration of the kin, feeling of pressure, hives, infection, inflammation, itching, lumps, numbness, pain, rash, redness, scarring, soreness, stinging, swelling, tenderness, tingling, ulceration, or warmth at the injection site; difficulty having a bowel movement (stool); dry mouth; headache; lack or loss of strength; loss of appetite; weight loss

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Last Updated: 3/11/2025

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