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Methadone (Injection)

Generic Name: methadone (METH-a-done)

Injection route(Solution)

QT interval prolongation and serious arrhythmias (torsades de pointes) have been observed during treatment with methadone. Only approved hospitals and pharmacies can dispense oral methadone for the treatment of narcotic addiction. Methadone can be dispensed in any licensed pharmacy when used as an analgesic. QT interval prolongation and serious arrhythmias (torsades de pointes) have been observed during treatment with methadone. Most cases involve patients being treated with higher doses (greater than 200 mg/day), although cases have been reported in patients receiving doses commonly used for maintenance treatment of opioid addiction .

Available Dosage Forms:

  • Solution

Therapeutic Class: Analgesic

Chemical Class: Opioid

Medically reviewed by Drugs.com. Last updated on Jul 27, 2020.

Uses for methadone

Methadone injection is used to treat moderate to severe pain when around-the-clock pain relief is needed for a long period of time. Methadone 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 (narcotic) analgesic (pain medicine). It acts on the nervous system to relieve pain.

Methadone is available only with your doctor's prescription.

Before using methadone

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 methadone, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to methadone 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.

Pediatric

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.

Geriatric

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.

Breastfeeding

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.

Interactions with 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 methadone, 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 methadone 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
  • Mesoridazine
  • Nalmefene
  • Naltrexone
  • Nelfinavir
  • Pimozide
  • Piperaquine
  • Posaconazole
  • Rasagiline
  • Safinamide
  • Saquinavir
  • Sparfloxacin
  • Terfenadine
  • Thioridazine
  • Ziprasidone

Using methadone 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.

  • Abametapir
  • Acepromazine
  • Alfentanil
  • Alfuzosin
  • Almotriptan
  • Alprazolam
  • Amineptine
  • Amiodarone
  • Amisulpride
  • Amitriptyline
  • Amitriptylinoxide
  • Amobarbital
  • Amoxapine
  • Amphetamine
  • Amprenavir
  • Anagrelide
  • Anileridine
  • Apomorphine
  • Aprepitant
  • Aripiprazole
  • Aripiprazole Lauroxil
  • Armodafinil
  • Arsenic Trioxide
  • Artemether
  • Asenapine
  • Astemizole
  • Azithromycin
  • Baclofen
  • Bedaquiline
  • Benperidol
  • Benzhydrocodone
  • Benzphetamine
  • Boceprevir
  • Bosentan
  • Bromazepam
  • Bromopride
  • Brompheniramine
  • Buprenorphine
  • Buserelin
  • Buspirone
  • Butabarbital
  • Butorphanol
  • Calcium Oxybate
  • Cannabidiol
  • Carbamazepine
  • Carbinoxamine
  • Cariprazine
  • Carisoprodol
  • Carphenazine
  • Ceritinib
  • Cetirizine
  • Chloral Hydrate
  • Chlordiazepoxide
  • Chloroquine
  • Chlorpheniramine
  • Chlorpromazine
  • Chlorzoxazone
  • Ciprofloxacin
  • Citalopram
  • Clarithromycin
  • Clobazam
  • Clofazimine
  • Clomipramine
  • Clonazepam
  • Clopidogrel
  • Clorazepate
  • Clozapine
  • Cobicistat
  • Cocaine
  • Codeine
  • Conivaptan
  • Crizotinib
  • Cyclobenzaprine
  • Cyclosporine
  • Dabrafenib
  • Dantrolene
  • Darunavir
  • Dasatinib
  • Degarelix
  • Delamanid
  • Delavirdine
  • Desipramine
  • Deslorelin
  • Desmopressin
  • Desvenlafaxine
  • Deutetrabenazine
  • Dexamethasone
  • Dexmedetomidine
  • Dextroamphetamine
  • Dextromethorphan
  • Dezocine
  • Diazepam
  • Dibenzepin
  • Dichloralphenazone
  • Difenoxin
  • Dihydrocodeine
  • Diltiazem
  • Diphenhydramine
  • Diphenoxylate
  • Disopyramide
  • Dofetilide
  • Dolasetron
  • Domperidone
  • Donepezil
  • Doxepin
  • Doxylamine
  • Droperidol
  • Duloxetine
  • Ebastine
  • Eletriptan
  • Encorafenib
  • Enflurane
  • Entrectinib
  • Enzalutamide
  • Eribulin
  • Erythromycin
  • Escitalopram
  • Esketamine
  • Eslicarbazepine Acetate
  • Estazolam
  • Eszopiclone
  • Ethchlorvynol
  • Ethopropazine
  • Ethylmorphine
  • Famotidine
  • Felbamate
  • Fenfluramine
  • Fentanyl
  • Fingolimod
  • Flecainide
  • Flibanserin
  • Fluoxetine
  • Fluphenazine
  • Flurazepam
  • Fluspirilene
  • Fluvoxamine
  • Formoterol
  • Fosaprepitant
  • Foscarnet
  • Fosnetupitant
  • Fosphenytoin
  • Fospropofol
  • Fostemsavir
  • Frovatriptan
  • Furazolidone
  • Gabapentin
  • Gabapentin Enacarbil
  • Galantamine
  • Gatifloxacin
  • Gemifloxacin
  • Glasdegib
  • Gonadorelin
  • Goserelin
  • Granisetron
  • Halazepam
  • Halofantrine
  • Haloperidol
  • Halothane
  • Hexobarbital
  • Histrelin
  • Hydrocodone
  • Hydromorphone
  • Hydroquinidine
  • Hydroxychloroquine
  • Hydroxytryptophan
  • Hydroxyzine
  • Ibutilide
  • Idelalisib
  • Iloperidone
  • Imatinib
  • Imipramine
  • Indinavir
  • Inotuzumab Ozogamicin
  • Iproniazid
  • Isocarboxazid
  • Isoflurane
  • Ivabradine
  • Ivacaftor
  • Ivosidenib
  • Ketamine
  • Ketazolam
  • Ketobemidone
  • Lapatinib
  • Lasmiditan
  • Lefamulin
  • Lemborexant
  • Lenvatinib
  • Levofloxacin
  • Levomilnacipran
  • Levorphanol
  • Linezolid
  • Lisdexamfetamine
  • Lithium
  • Lofepramine
  • Lofexidine
  • Lomitapide
  • Lopinavir
  • Lorazepam
  • Lorcaserin
  • Loxapine
  • Lumacaftor
  • Lumefantrine
  • Lurasidone
  • Macimorelin
  • Magnesium Oxybate
  • Meclizine
  • Mefloquine
  • Melitracen
  • Melperone
  • Meperidine
  • Mephobarbital
  • Meprobamate
  • Meptazinol
  • Metaxalone
  • Methamphetamine
  • Methdilazine
  • Methocarbamol
  • Methohexital
  • Methotrimeprazine
  • Methylene Blue
  • Metoclopramide
  • Metronidazole
  • Mibefradil
  • Midazolam
  • Mifepristone
  • Milnacipran
  • Mirtazapine
  • Mitotane
  • Mizolastine
  • Moclobemide
  • Modafinil
  • Molindone
  • Moricizine
  • Morphine
  • Morphine Sulfate Liposome
  • Moxifloxacin
  • Nafarelin
  • Nafcillin
  • Nalbuphine
  • Naratriptan
  • Nefazodone
  • Netupitant
  • Nialamide
  • Nicomorphine
  • Nilotinib
  • Nitrazepam
  • Nitrous Oxide
  • Norfloxacin
  • Nortriptyline
  • Octreotide
  • Ofloxacin
  • Olanzapine
  • Ondansetron
  • Opipramol
  • Opium
  • Opium Alkaloids
  • Orphenadrine
  • Osilodrostat
  • Osimertinib
  • Oxaliplatin
  • Oxazepam
  • Oxcarbazepine
  • Oxycodone
  • Oxymorphone
  • Ozanimod
  • Palbociclib
  • Paliperidone
  • Palonosetron
  • Panobinostat
  • Papaveretum
  • Papaverine
  • Paregoric
  • Paroxetine
  • Pasireotide
  • Pazopanib
  • Peginterferon Alfa-2b
  • Pentamidine
  • Pentazocine
  • Pentobarbital
  • Perampanel
  • Perazine
  • Periciazine
  • Perphenazine
  • Phenelzine
  • Phenobarbital
  • Phenytoin
  • Pimavanserin
  • Pipamperone
  • Piperacetazine
  • Pipotiazine
  • Piritramide
  • Pitolisant
  • Potassium Oxybate
  • Prazepam
  • Prednisone
  • Pregabalin
  • Primidone
  • Probucol
  • Procainamide
  • Procarbazine
  • Prochlorperazine
  • Promazine
  • Promethazine
  • Propafenone
  • Propofol
  • Protriptyline
  • Quazepam
  • Quetiapine
  • Quinidine
  • Quinine
  • Ramelteon
  • Ranitidine
  • Ranolazine
  • Remifentanil
  • Remimazolam
  • Remoxipride
  • Ribociclib
  • Rifabutin
  • Rifampin
  • Rifapentine
  • Ritonavir
  • Rizatriptan
  • Scopolamine
  • Secobarbital
  • Selegiline
  • Selpercatinib
  • Sertindole
  • Sertraline
  • Sevoflurane
  • Sibutramine
  • Siponimod
  • Sodium Oxybate
  • Sodium Phosphate
  • Sodium Phosphate, Dibasic
  • Sodium Phosphate, Monobasic
  • Solifenacin
  • Sorafenib
  • Sotalol
  • St John's Wort
  • Sufentanil
  • Sulpiride
  • Sunitinib
  • Suvorexant
  • Tacrolimus
  • Tamoxifen
  • Tapentadol
  • Telaprevir
  • Telavancin
  • Telithromycin
  • Temazepam
  • Tetrabenazine
  • Thiethylperazine
  • Thiopental
  • Thiopropazate
  • Thiothixene
  • Tianeptine
  • Tilidine
  • Tipranavir
  • Tizanidine
  • Tolonium Chloride
  • Topiramate
  • Toremifene
  • Tramadol
  • Tranylcypromine
  • Trazodone
  • Triazolam
  • Triclabendazole
  • Trifluoperazine
  • Trifluperidol
  • Triflupromazine
  • Trimeprazine
  • Trimipramine
  • Triptorelin
  • Tryptophan
  • Vandetanib
  • Vardenafil
  • Vemurafenib
  • Venlafaxine
  • Verapamil
  • Vilanterol
  • Vilazodone
  • Vinflunine
  • Voriconazole
  • Vorinostat
  • Vortioxetine
  • Zaleplon
  • Zolmitriptan
  • Zolpidem
  • Zopiclone
  • Zotepine
  • Zuclopenthixol

Using methadone 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.

  • Abacavir
  • Atazanavir
  • Didanosine
  • Etravirine
  • Fosamprenavir
  • Nevirapine
  • Peginterferon Alfa-2a
  • Stavudine
  • Zidovudine

Interactions with food/tobacco/alcohol

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 methadone 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 methadone, 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 methadone. Make sure you tell your doctor if you have any other medical problems, especially:

  • Alcohol abuse, 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 narcotic abuse 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.
  • 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 methadone

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

Precautions while using methadone

It is very important that your doctor check your progress while you are using methadone. 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 methadone if you are using or have used an MAO inhibitor within the past 14 days.

Methadone may cause serious allergic reactions, including anaphylaxis. Anaphylaxis can be life-threatening and requires 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 methadone.

Methadone 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 narcotics, 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 methadone. Check with your doctor before taking any of the other medicines listed above while you are using methadone.

Do not use more of methadone 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.

Methadone 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 methadone.

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 methadone 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.

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.

Methadone 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 narcotics 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 methadone 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 narcotic for a while, to lessen the chance of withdrawal side effects.

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.

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

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

Using too much of methadone may cause infertility (unable to have children). Talk with your doctor before using methadone 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.

Methadone side effects

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
  • 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

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.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Frequently Asked Questions