What is methadone?


Generic Name: Methadone Brand Name(s): Generics only. No brands available.

Know the basics

What is methadone used for?

Methadone is used to treat severe ongoing pain (such as due to cancer). Methadone belongs to a class of drugs known as narcotic (opiate) analgesics. It works in the brain to change how your body feels and responds to pain.

Do not use methadone to relieve pain that is mild or that will go away in a few days (such as pain from surgery). Methadone is not for occasional (“as needed”) use.

Methadone is also used to treat addiction to narcotic drugs (such as heroin) as part of an approved treatment program. It helps prevent withdrawal symptoms caused by stopping other narcotic drugs.

How should I take methadone?

Take methadone by mouth on a regular schedule as directed by your doctor and not as needed for sudden (breakthrough) pain. You may take this drug with or without food. If you have nausea, it may help to take this drug with food. Ask your doctor or pharmacist about other ways to decrease nausea (such as lying down for 1 to 2 hours with as little head movement as possible).

If you are using the liquid form of methadone, measure the dose carefully using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose.

The dosage is based on your medical condition and response to treatment.

Methadone may cause withdrawal reactions, especially if it has been used regularly for a long time or in high doses. In such cases, withdrawal symptoms (such as restlessness, watering eyes, runny nose, nausea, sweating, muscle aches) may occur if you suddenly stop using methadone. To prevent withdrawal reactions, your doctor may reduce your dose gradually. Consult your doctor or pharmacist for more details, and report any withdrawal reactions immediately.

When methadone is used for a long time, it may not work as well. Talk with your doctor if methadone stops working well.

Methadone may rarely cause abnormal drug-seeking behavior (addiction). This risk may be increased if you have abused alcohol or drugs in the past. Take methadone exactly as prescribed to lessen the risk of addiction. Stopping methadone maintenance treatment has a high risk of return to narcotic drug abuse.

Tell your doctor if your condition persists or worsens.

How do I store methadone?

Methadone is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store methadone in the bathroom or the freezer. There may be different brands of methadone that may have different storage needs. It is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush methadone down the toilet or pour them into a drain unless instructed to do so. It is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Know the precautions & warnings

What should I know before using methadone?

Before taking methadone,

  • Tell your doctor and pharmacist if you are allergic to methadone, any other medications, or any of the ingredients in the methadone product you plan to take. Ask your doctor or pharmacist or check the methadone guide for a list of the ingredients.
  • Tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, and nutritional supplements you are taking or plan to take. Be sure to mention these medications: antihistamines; buprenorphine (suboxone, in zubsolv); butorphanol; calcium channel blocking agents such as carbamazepine (cabatrol, equetro, tegretol); fluvoxamine (luvox); certain medications for hiv including abacavir (ziagen, in trizivir), darunavir (prezista), didanosine (videx), efavirenz (sustiva, in atripla), lopinavir (in kaletra), nelfinavir (viracept), nevirapine (viramune), ritonavir (norvir, in kaletra), saquinavir (invirase), stavudine (zerit), telaprevir (incivek), tipranavir (aptivus), and zidovudine (retrovir, in combivir); medications for glaucoma, irritable bowel disease, parkinson’s disease, ulcers, and urinary problems; nalbuphine; naloxone (in zubsolv); naltrexone (revia, depade); pentazocine (talwin); phenobarbital; phenytoin (dilantin); and rifampin (rifadin, rimactane, in rifamate, in rifater). Also tell your doctor or pharmacist if you are taking the following medications or have stopped taking them in the past 14 days: monoamine oxidase (mao) inhibitors including isocarboxazid (marplan), phenelzine (nardil), selegiline (eldepryl, emsam, zelpar), and tranylcypromine (parnate). Many other medications may also interact with methadone, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
  • Tell your doctor what herbal products you are taking, especially st. John’s wort.
  • Tell your doctor if you have any of the conditions like paralytic ileus (condition in which digested food does not move through the intestines). Your doctor may tell you that you should not take methadone.
  • Tell your doctor if you have or have ever had a blockage in your intestine; difficulty urinating; an enlarged prostate (a male reproductive gland); addison’s disease (a condition in which the adrenal gland does not make enough of certain natural substances); seizures; or thyroid, pancreas, gallbladder, liver, or kidney disease.
  • Tell your doctor if you are breast-feeding. If you breast-feed during your treatment with methadone, your baby may receive some methadone in breastmilk. Watch your baby closely for any changes in behavior or breathing, especially when you start taking methadone. If your baby develops any of these symptoms, call your baby’s doctor immediately or get emergency medical help: unusual sleepiness, difficulty breastfeeding, difficulty breathing, or limpness. Talk to your baby’s doctor when you are ready to wean your baby. You will need to wean your baby gradually so that your baby will not develop withdrawal symptoms when he or she stops receiving methadone in breastmilk.
  • If you are having surgery, including dental surgery, tell the doctor or dentist that you are taking methadone.
  • You should know that methadone may make you drowsy. Do not drive a car or operate machinery until you know how methadone affects you.
  • You should know that methadone may cause dizziness when you get up too quickly from a lying position. This is more common when you first start taking methadone. To avoid this problem, get out of bed slowly, resting your feet on the floor for a few minutes before standing up.
  • You should know that methadone may cause constipation. Talk to your doctor about changing your diet or using other medications to prevent or treat constipation while you are taking methadone.

Is it safe to take methadone during pregnancy or breast-feeding?

There are no adequate studies in women for determining risk when using methadone during pregnancy or while breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking methadone. Methadone is pregnancy risk category C according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

  • A=No risk,
  • B=No risk in some studies,
  • C=There may be some risk,
  • D=Positive evidence of risk,
  • X=Contraindicated,
  • N=Unknown

Know the side effects

What are the side effects of methadone?

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have any of these serious side effects:

  • Shallow breathing;
  • Hallucinations or confusion;
  • Chest pain, dizziness, fainting, fast or pounding heartbeat; or
  • Trouble breathing, feeling light-headed, or fainting.

Less serious side effects may include:

  • Feeling anxious, nervous, or restless;
  • Sleep problems (insomnia);
  • Feeling weak or drowsy;
  • Dry mouth, nausea, vomiting, diarrhea, constipation, loss of appetite; or
  • Decreased sex drive, impotence, or difficulty having an orgasm.

Not everyone experiences these side effects. There may be some side effects not listed above. If you have any concerns about a side-effect, please consult your doctor or pharmacist.

Know the interactions

What drugs may interact with methadone?

Methadone may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.

Taking this medicine with other drugs that make you sleepy or slow your breathing can cause dangerous or life-threatening side effects. Ask your doctor before taking methadone with a sleeping pill, narcotic pain medicine, muscle relaxer, or medicine for anxiety, depression, or seizures.

Does food or alcohol interact with methadone?

Methadone may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with methadone?

Methadone may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have, especially:

  • Alcohol abuse, or history of;
  • Brain tumor;
  • Breathing or lung problems (eg, chronic obstructive pulmonary disease [COPD], cor pulmonale, hypercapnia, hypoxia, apnea);
  • Depression, history of;
  • Drug dependence, especially narcotic abuse or dependence, history of;
  • Gallbladder disease;
  • Head injuries, history of;
  • Heart disease (eg, cardiac hypertrophy);
  • Heart rhythm problems (eg, arrhythmia, long QT syndrome), or history of;
  • Hypokalemia (low potassium in the blood);
  • Hypomagnesemia (low magnesium in the blood) ;
  • Increased pressure in your head;
  • Stomach or bowel problems;
  • Weakened physical condition—Use with caution. May increase risk for more serious side effects.
  • Asthma, acute or severe;
  • Paralytic ileus (intestinal blockage);
  • Respiratory depression (very slow breathing)—Should not be used in patients with these conditions.
  • Hypotension (low blood pressure);
  • Pancreatitis (inflammation of the pancreas) or
  • Seizures, history of—Use with caution. May make these conditions worse.
  • Kidney disease;
  • Liver disease—Use with caution. The effects may be increased because of slower removal of the medicine from the body.

Understand the dosage

The information provided is not a substitute for any medical advice. You should ALWAYS consult with your doctor or pharmacist before using methadone.

What is the dose of methadone for an adult?

Usual Adult Dose for Pain

  • Oral: Starting dose 2.5 mg to 10 mg every 8 to 12 hours.
  • Intravenous, intramuscular, subcutaneously: Starting dose 2.5 mg to 10 mg every 8 to 12 hours.

Usual Adult Dose for Opiate Withdrawal

  • Initial Dose: 15 to 40 mg once a day.
  • After one or two days, a 20% daily reduction in dose can usually be tolerated.
  • Detoxification can usually be completed within 10 days.
  • Maintenance of opioid dependence: 20 to 120 mg/day.

What is the dose of methadone for a child?

Neonatal abstinence syndrome:         

  • Oral or Intravenous:
  • Initial: 0.05 to 0.2 mg/kg/dose given every 12 to 24 hours or 0.5 mg/kg/day divided every 8 hours.
  • Individualize dose and tapering schedule to control symptoms of withdrawal. Usually taper dose by 10 to 20% per week over 1 to 1 and 1/2 months.
  • Note: Due to long elimination half-life, tapering is difficult; consider alternate agent.


  • Analgesia: Dosing interval may range from 4 to 12 hours during initial therapy. Decrease in dose or frequency may be required approximately 2 to 5 days after initiation of therapy or dosage increase due to accumulation with repeated doses.
  • Intravenous: Initial: 0.1 mg/kg/dose every 4 hours for 2 to 3 doses, then every 6 to 12 hours as needed. Maximum dose: 10 mg/dose;
  • Oral, intramuscular, Subcutaneous: Initial: 0.1 mg/kg/dose every 4 hours for 2 to 3 doses, then every 6 to 12 hours as needed or 0.7 mg/kg/24 hours divided every 4 to 6 hours as needed. Maximum dose: 10 mg/dose.
  • Iatrogenic narcotic dependency:
  • Oral: Controlled studies have not been conducted. Several clinically used dosing regimens have been reported. Methadone dose must be individualized and will depend upon the previous narcotic dose and severity of opioid withdrawal. Patients who have received higher doses of narcotics will require higher methadone doses.

General guidelines:

  • Initial: 0.05 to 0.1 mg/kg/dose every 6 hours;
  • Increase by 0.05 mg/kg/dose until withdrawal symptoms are controlled. After 24 to 48 hours, the dosing interval can be lengthened to every 12 to 24 hours. To taper dose, wean by 0.05 mg/kg/day. If withdrawal symptoms recur, taper at a slower rate.

How is methadone available?

Methadone is available in the following dosage forms and strengths:

  • Tablet, Oral: 40 mg.

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to your nearest emergency room.

What should I do if I miss a dose?

If you miss a dose of methadone, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Review Date: May 30, 2016 | Last Modified: January 4, 2017

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