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What is methadone?

Methadone is a generic drug also sold under the brand names Dolophine and Methadose¹.

It has a high potential for abuse and is listed as a Schedule II drug² by the US Drug Enforcement Administration (the DEA). It can only legally be taken under medical supervision.

It is a synthetic opioid that belongs to a class of drugs called opiate (narcotic) analgesics. It’s in the same class of drugs as oxycodone and morphine.

It helps ease moderate to severe pain by changing how the brain and nervous system react to it.

It can also be used to help people who are addicted to opioids. It helps them transition into medication-assisted treatment (MAT), preventing withdrawal symptoms.

What is methadone used to treat?

Methadone may be prescribed to ease moderate to severe pain in people who cannot take other medications and are expected to need continuous pain medication for days or weeks.

It may also be used to prevent opiate drug withdrawal symptoms in people taking part in addiction treatment programs. It can help them quit taking or continue not to take substances.

The drug binds to the same receptors as other opioids. However, it has a slightly shorter onset of action, meaning its effects could take longer to show (about 30 to 45 minutes). It also has a much longer half-life. This means the drug stays in the blood in relatively high concentrations for long periods (ranging from 24 to 55 hours, depending on the individual).

Often, only one dose is needed per day to prevent withdrawal symptoms. However, its analgesic effects usually wear off faster, requiring dosing every eight to 12 hours.

How do you take methadone?

Methadone is available as tablets, dispersible (dissoluble) tablets, liquids, and concentrates for oral use. Dispersible tablets should be dissolved in water or a flavored drink.

You can take the drug every eight to 12 hours³ to relieve pain, but you must follow your doctor’s specific advice.

You should only take methadone to treat other opiate addictions under close medical supervision. Your prescribed dosage regimen will vary based on a number of factors. A specialist should be monitoring the process to ensure it’s effective and you are safe.

Seeing results

Methadone may reduce pain for up to eight hours, but the drug stays in the body for much longer.

Potential side effects of methadone

The DEA considers methadone a Schedule II controlled substance. This means the drug has a high potential for abuse. Not following your doctor’s instructions can increase your risk of developing physical and psychological dependency.

Only take methadone under close medical supervision.

Mild/moderate side effects

Potential mild/moderate side effects of methadone include:

  • Drowsiness

  • Nausea

  • Vomiting

  • Constipation

  • Dry mouth

  • Sweating

  • Itching

  • Headache

  • Dizziness

  • Difficulty sleeping

  • Mood changes, such as anxiety or depression

Contact your doctor if these side effects worsen or persist.

Serious side effects

Methadone can also cause serious side effects. Seek urgent medical care if you develop any of the symptoms described below:

Respiratory failure (not being able to breathe). Pay close attention to the following symptoms, particularly in the first 24 to 72 hours after taking methadone for the first time. Symptoms can include:

  • Shortness of breath

  • Chest pain

  • Lightheadedness

  • Feeling faint

  • Slowed or very shallow breathing

  • Dizziness

  • Confusion

Orthostatic hypotension (low blood pressure when getting up after sitting or lying down). Symptoms can include:

Physical dependence and withdrawal when stopping the drug. Symptoms can include:

  • Restlessness

  • Irritability or anxiousness

  • Trouble sleeping

  • Increased blood pressure

  • Fast breathing rate

  • Fast heart rate

  • Dilated pupils (enlargement of the dark center of the eyes)

  • Teary eyes

  • Runny nose

  • Yawning

  • Nausea, vomiting, and a loss of appetite

  • Diarrhea and stomach cramps

  • Sweating

  • Chills

  • Muscle aches and backache

Misuse or addiction. Symptoms can include:

  • Taking more of the drug than prescribed

  • Taking the drug regularly, even if you don’t need it

  • Continuing to use the drug despite it negatively affecting your relationships or job

  • Continuing use even after legal consequences

  • Ignoring your regular responsibilities

  • Taking the drug secretly or lying about how much you are taking

You may also experience seizures as a serious side effect of methadone.

Long-term use of methadone

Taking methadone for a long time may increase your risk of developing a tolerance to it.

Becoming tolerant to medication means you need higher doses to experience the same effects, which could lead to addiction. It may also cause withdrawal effects if you suddenly reduce or stop taking the drug.

Long-term methadone use can damage parts of your body, including your liver, nerves, and brain⁴.

Missed doses

If you’re taking methadone to treat pain, you should take the missed dose as soon as possible. If it’s nearly time for the next dose, skip the missed dose and return to your normal regimen.

If you’re using this medicine as replacement therapy for opioid dependency, skip your missed dose altogether and resume your normal medication schedule the next day.

In either case, never take two doses at once or too close together as this could lead to an overdose.


Methadone has been linked to many overdose deaths⁵, but it is also one of the most effective treatments for addiction to opioids like heroin and morphine. When used as prescribed, methadone is relatively safe — but it still carries some risks based on a variety of factors that involve its metabolism. It can also be addictive.

Symptoms of methadone overdose include:

  • Trouble breathing

  • Slow or shallow breathing

  • Feeling sleepy or drowsy

  • Small pupils

  • Skin that is blue, cool, or clammy

  • Muscle limpness

  • Inability to wake up or respond

Seek urgent medical assistance if you think you or someone else has taken too much methadone.

What to discuss with your doctor before taking methadone

Before taking methadone, tell your doctor if:

  • You know that you are allergic to methadone, any other medicines, or any of the ingredients in the methadone product you want to take.

  • You are taking prescription drugs (particularly any antipsychotic or antidepressant drugs, sedatives, cardiovascular medications, or any other narcotics), over-the-counter drugs, vitamins, or nutritional supplements. You should also tell them if you plan to start taking any of these substances while undergoing methadone treatment.

  • You have any respiratory issues.

  •  You have liver or cardiovascular disease.

  • You are breastfeeding, pregnant, or planning to become pregnant during your treatment.

Methadone has been linked to reduced fertility in males. It may cause hormonal changes and irregular menstruation in females. Discuss the side effects of methadone with your doctor before taking it.

Tell any medical or dental professional that you are taking methadone before undergoing surgery.

Stopping methadone

You may experience physical withdrawal and dependence when you stop taking the drug. The following are some of the possible symptoms:

  • Restlessness

  • Irritability or anxiousness

  • Trouble sleeping

  • Increased blood pressure

  • Fast breathing rate

  • Fast heart rate

  • Dilated pupils (enlargement of the dark center of the eyes)

  • Teary eyes

  • Runny nose

  • Yawning

  • Nausea, vomiting, and loss of appetite

  • Diarrhea and stomach cramps

  • Sweating

  • Chills

  • Muscle aches and backache

Don’t stop taking this drug without your doctor’s guidance. Tell them immediately if you develop withdrawal symptoms.

Methadone and pregnancy

If you are pregnant or thinking about getting pregnant, talk to your doctor. This medication should only be used if the potential benefit outweighs the associated risk.

Methadone is a pregnancy category C drug⁶, meaning animal studies have shown adverse effects on the fetus. However, not enough well-controlled human studies have proven the same.

Contact your doctor immediately if you become pregnant while taking methadone. It could cause your baby to develop neonatal abstinence syndrome, a potentially life-threatening condition that requires emergency medical treatment. Discuss the benefits and risks of continuing treatment with your doctor.

Methadone and breastfeeding

Methadone can enter the breast milk and transfer to a nursing baby, with most receiving just 1–3%⁷ of their mother’s weight-adjusted dosage.

Continuing methadone treatment while breastfeeding is generally safe and may be recommended. However, a specialist will need to monitor your dose closely.

Your baby may be at risk of more serious adverse effects like sedation and respiratory depression if:

  • Your dose is increased to 100mg per day (either as part of your treatment or through methadone abuse).

  • You start methadone treatment postpartum. This is because your baby will not have been exposed to methadone during pregnancy and has a very low tolerance.

Don’t take methadone while breastfeeding without consulting your doctor.

Interactions with other drugs

Methadone can interact with other drugs, both prescription and over-the-counter. Some interactions can be dangerous, while others may only cause a minor change in the way methadone works.

Tell your doctor about all the medications you are taking, including vitamins and supplements, to avoid harmful interactions.

Many drugs interact with methadone. You will find some of the medications that interact the most with methadone below. They interact by:

  1. Reducing the level of methadone in the blood, causing withdrawal symptoms.

  2. Increasing the level of methadone in the blood, causing overdose and potentially coma or death.

  3. Affecting your body and nervous system similarly to methadone, hence increasing the impact. This can cause major sedative effects, irregular heartbeat, coma, respiratory failure, or death.

Medications that may interact with methadone include:

  • Other narcotics/opioids, like nalbuphine, butorphanol, pentazocine, and buprenorphine.

  • Antibiotics, like rifampicin (Rifadin and Rimactane), erythromycin (ERY-C, ERY-Tab, Erythrocin), and clarithromycin (Biaxin).

  • Sedatives, such as benzodiazepines, clonazepam (Klonopin), temazepam (Restoril), diazepam (Valium), lorazepam (Ativan), and alprazolam (Xanax).

  • Antipsychotics, like olanzapine (Zyprexa), clozapine (Clozaril, FazaClo ODT, Versacloz), quetiapine (Seroquel).

  • Monoamine oxidase (MAO) inhibitors (a type of antidepressant) like phenelzine (Nardil) and isocarboxazid (Marplan).

  • Selective serotonin-reuptake inhibitors (SSRIs) (a type of antidepressant) such as fluoxetine (Prozac) and escitalopram (Lexapro).

  • Anti-allergy/antihistamines, like hydroxyzine (Vistaril) and diphenhydramine (Benadryl).

  • Antifungal drugs, like posaconazole (Noxafil), voriconazole (Vfend), and ketoconazole (Nizorale).

  • Some HIV drugs, like ritonavir (Norvir) and saquinavir (Invirase).

  • Some cardiovascular medications used to treat hypertension or heart conditions, such as diuretics (water pills), amiodarone (Cordarone and Pacerone), ibutilide fumarate (Corvert).

This is NOT an exhaustive list of all the medications methadone interacts with.

You must discuss your medical history, including health conditions, medications, or supplements that you are taking, with your doctor.

Allergy information

Methadone can cause a severe allergic reaction.

Symptoms include:

  • Itching

  • Hives

  • Trouble breathing

  • Swelling of your throat, tongue, hand, and face.

Seek emergency medical help if you experience any of these symptoms.

Don’t take this medicine again if you had an allergic reaction to it in the past.

Clinical trial history

Methadone hydrochloride has been the major treatment for opiate addiction for over three decades.

In 1947⁸, the Food and Drug Administration (FDA) authorized methadone for pain-relieving and antitussive (cough-relieving) applications.

In the mid-1960s, researchers demonstrated methadone could successfully treat opiate addiction. The FDA approved the drug for this use in 1972.

Tips and advice for taking methadone

Here are some tips to help you take methadone safely and get the most from your treatment:

  • Take methadone on a regular schedule. Taking it at the same time each day will help keep drug levels consistent in your blood and reduce your chance of missing a dose.

  • Don’t stop taking methadone without talking to your doctor first. Stopping suddenly can cause withdrawal effects.

  • Tell your doctor if you have any respiratory, liver, or cardiovascular issues.

  • Be careful when drinking alcohol while taking methadone. This combination could be dangerous. Drinking too much while taking methadone can increase the risk of serious side effects.

  • Tell your doctor if you’re planning to get pregnant or if you become pregnant while taking methadone.

  • Take methadone exactly as prescribed. Don’t take more or less than what your doctor recommends.

Curious about clinical trials?

Access the latest treatments and medications. unavailable elsewhere - entirely free of charge. We make it easy to take part.


Here at HealthMatch, we’ve done our best to ensure that the information provided in this article is helpful, up to date, and, most importantly, accurate.

However, we can’t replace the one-to-one advice of a qualified medical practitioner or outline all of the possible risks associated with this particular drug and your circumstances.

It is therefore important for you to note that the information contained in this article does not constitute professional medical or healthcare advice, diagnosis or recommendation of treatment and is not intended to, nor should be used to, replace professional medical advice. This article may not always be up to date and is not exhaustive of all of the risks and considerations relevant to this particular drug. In no circumstances should this article be relied upon without independent consideration and confirmation by a qualified medical practitioner.

Your doctor will be able to explain all possible uses, dosages, precautions, interactions with other drugs, and other potential adverse effects, and you should always talk to them about any kind of medication you are taking, thinking about taking or wanting to stop taking.

Curious about clinical trials?

Access the latest treatments and medications. unavailable elsewhere - entirely free of charge. We make it easy to take part.