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Methadone - Brand name: Physeptone

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  1. About methadone
  2. Key facts
  3. Who can and cannot take methadone
  4. How and when to take methadone
  5. Side effects of methadone
  6. How to cope with side effects of methadone
  7. Pregnancy and breastfeeding
  8. Cautions with other medicines
  9. Common questions about methadone

1. About methadone

Methadone is a man-made opioid (also known as an opiate). Other opioids include codeine, morphine, fentanyl and diamorphine (heroin).

Methadone is used to help you stop taking heroin. It reduces your withdrawal symptoms, such as shaking, shivering and other flu-like symptoms. It also helps stop cravings.

There are 2 main approaches to stopping heroin:

  • maintenance therapy – where you switch from heroin to a heroin substitute like methadone, then stay on a stable dose of the substitute. You will usually take this long term
  • detox (detoxification) – where you switch from heroin to a substitute like methadone, before gradually withdrawing from the substitute so you're completely free from both

Some people start taking methadone for maintenance therapy. However many of them go on to detox and become free of heroin and methadone.

Methadone is available on prescription only.

If you're having treatment for heroin addiction (dependence), methadone usually comes as a green liquid. You'll get your prescription from your GP or local drug treatment service.

Methadone is also used for end of life care and severe pain. This is usually prescribed by a pain specialist and comes as tablets or injections.


If you take heroin and want to stop, you can ask a GP or local drug treatment service for help with heroin addiction. You're entitled to the same confidential NHS care as anyone else.

Find your local drug treatment service

2. Key facts

  • To get methadone for drug dependence you need to get in touch with your GP or local drug treatment service. You'll have a named key worker.
  • The most common side effects of methadone are constipation, feeling sick, and feeling cold and sweaty.
  • It's best to avoid alcohol while taking methadone, as it can cause very serious side effects. For this reason it's important to tell your prescriber how much you drink.
  • You’ll usually have a urine or saliva test every few weeks at your GP surgery or local drug treatment service. This is to check for heroin, heroin substitutes and other drugs.
  • Methadone is addictive, like all opioids. If you are taking it to detox, your treatment plan will include details for gradually reducing then stopping your dose.

3. Who can and cannot take methadone

Adults (aged 18 years and over) can take methadone for drug addiction.

It can also be given to newborn babies in hospital, to help with heroin or methadone withdrawal symptoms.

Methadone may not be suitable for some people. Tell your doctor before starting methadone treatment if you:

  • have had an allergic reaction to methadone or any other medicines in the past
  • have a lung problem or breathing difficulties
  • are addicted to alcohol, or other drugs that are not opioid
  • have a head injury or get bad headaches
  • have ulcerative colitis
  • have seizures or fits
  • have heart rhythm problems (arrhythmia) or low blood pressure
  • have problems with your thyroid, adrenal glands, kidneys or liver
  • have myasthenia gravis (a rare condition that causes muscle weakness)
  • are pregnant, trying to get pregnant or breastfeeding

4. How and when to take methadone

Always follow the instructions that come with your medicine.

With liquid methadone, swallow the medicine in one go. You can have a drink of water afterwards if you like.

Dosage for heroin addiction

Doses vary from person to person. Your starting dose is based on:

  • the amount of heroin you are using
  • whether you are using other drugs or alcohol
  • a urine sample (to test for heroin and other drugs)
  • your physical and mental health
  • whether you have had treatment for drug addiction before

You will usually start on 10mg to 30mg, taken once a day. This can be increased slowly, until your withdrawal symptoms are under control and your cravings stop.

Many people then take a regular dose of between 60mg and 120mg a day. However your dose may be different. Always follow your treatment plan.

Getting your prescription

You will get your first prescription (or script) from your GP, or a prescriber at your drug treatment service. This may be a nurse, doctor or a prescribing pharmacist.

They will ask you to choose a pharmacy to take your prescriptions to. You can pick a pharmacy near your home or work.

To begin with, you'll usually visit the pharmacy every day and take your methadone there. Speak to your prescriber if that's going to be difficult.

Supervised doses

When you start your treatment, and until your dose is stabilised, a key worker or pharmacist will usually supervise you as you take methadone. This can take up to 3 months.

When you have stabilised on methadone, it may be possible to take some of your doses at home. You'll discuss this with your key worker and prescriber to work out what is right for you.

How long will I take it for?

If you're taking methadone for maintenance therapy, you will usually take it long term.

If you're taking it for detox, your dose will gradually be reduced until you do not need to take it anymore. This can take up to 12 weeks. It can sometimes be quicker, for example if you're detoxing in hospital or residential rehab.

What if I miss my dose?

If you take methadone at home

Take it as soon as you remember, unless it's nearly time for your next dose. In this case, skip the missed dose and take your next one at the usual time. Do not take a double dose to make up for a forgotten dose.

Tell your key worker or your doctor that you missed a dose. They may ask you to return the leftover liquid.

If you have supervised doses

Go to your pharmacy or drug treatment centre as soon as you remember, as long as it’s during opening hours.

If you cannot get to your pharmacy or drug treatment centre until the next day, they may not be able to give you any methadone. They may need to speak to your prescriber first.

It’s important to take your methadone or collect your doses on the right day. Always check your treatment plan.

What if I take too much?

It is important to take the right dose, according to your treatment plan and prescription.

If you take too much methadone you could be at risk of overdose. Too much methadone may make you very sleepy, and can slow down or stop your breathing. This can be life-threatening.

If you have been given naloxone and have taken too much methadone, or you’re having serious side effects, take the naloxone immediately. Follow the instructions you have been given. Naloxone is a medicine that is sometimes used to reverse a methadone overdose.

Urgent advice: Contact your doctor or key worker now if:

  • you take too much methadone, even if you feel well

Immediate action required: Call 999 or go to A&E if:

You have taken too much methadone and:

  • you feel very drowsy or you're finding it difficult to breathe

It’s also important to tell your key worker or doctor that you’ve taken too much. This is because you will run out of methadone before you get your next supply.

They will help you make a new treatment plan.

5. Side effects of methadone

Like all medicines, methadone can cause side effects. However, many people have no side effects or only minor ones.

You are more likely to get side effects if you are on a high dose of methadone.

Common side effects

These common side effects happen in more than 1 in 100 people.

Talk to your doctor, pharmacist or key worker if the side effects bother you or do not go away:

  • constipation
  • feeling or being sick (nausea or vomiting)
  • feeling sleepy, tired or dizzy
  • mild headache
  • feeling cold and sweating more than usual
  • dry eyes, mouth and nose
  • seeing things that are not there (hallucinations), changes in mood or feeling confused

Serious side effects

Serious side effects happen in less than 1 in 100 people.

Immediate action required: Call 999 now if:

  • you have problems breathing, shallow breath or shortness of breath – if you have been given naloxone take it immediately and follow the instructions that come with it
  • your heartbeat is irregular, or faster or slower than usual – these can be signs of a heart rhythm problem (arrhythmia)
  • you have temporary loss of vision or a constant throbbing headache which gets worse when coughing or straining – this can be due to build-up of pressure around the brain (intracranial hypertension)

Serious allergic reaction

In rare cases, it's possible to have a serious allergic reaction (anaphylaxis) to methadone.

Immediate action required: Call 999 now if:
  • your lips, mouth, throat or tongue suddenly become swollen
  • you're breathing very fast or struggling to breathe (you may become very wheezy or feel like you're choking or gasping for air)
  • your throat feels tight or you're struggling to swallow
  • your skin, tongue or lips turn blue, grey or pale (if you have black or brown skin, this may be easier to see on the palms of your hands or soles of your feet)
  • you suddenly become very confused, drowsy or dizzy
  • someone faints and cannot be woken up
  • a child is limp, floppy or not responding like they normally do (their head may fall to the side, backwards or forwards, or they may find it difficult to lift their head or focus on your face)

You or the person who's unwell may also have a rash that's swollen, raised, itchy, blistered or peeling.

These can be signs of a serious allergic reaction and may need immediate treatment in hospital.

These are not all the side effects of methadone. For a full list, see the leaflet inside your medicines packet.


You can report any suspected side effect using the Yellow Card safety scheme.

Visit Yellow Card for further information.

6. How to cope with side effects of methadone

Some of these side effects usually improve with time, as you get used to methadone.

What to do about:

  • constipation – try to get more fibre into your diet by eating fresh fruit and vegetables and cereals. Try to drink several glasses of water or other non-alcoholic liquid each day. If you can, it may also help to do some exercise. If your symptoms do not go away, speak to a pharmacist or doctor about medicine to help prevent or treat constipation caused by methadone.
  • feeling or being sick – this usually wears off after a few days. Talk to your doctor if it carries on for longer. If you're being sick, try small frequent sips of water to avoid dehydration.
  • feeling sleepy, tired or dizzy – this usually wears off within a couple of weeks as your body gets used to methadone. Talk to your doctor if these side effects carry on for longer. Do not drive or ride a bike if you’re feeling tired or dizzy.
  • mild headache – make sure you rest and drink plenty of fluids. Ask your pharmacist to recommend a painkiller. Headaches will usually go away after the first week of using methadone. If they are severe or last longer than a week, talk to your doctor.
  • feeling cold and sweating more than usual – speak to your prescriber if this lasts for more than a couple of days. They may need to adjust your dose.
  • dry eyes, mouth and nose – this will usually improve with time, as you get used to methadone. For dry eyes, ask a pharmacist for advice about eye drops called artificial tears. For a dry mouth, have frequent sips of water or other cold drinks.
  • seeing things that are not there (hallucinations), changes in mood or feeling confused – talk to your doctor or prescriber. They may need to adjust your dose.

7. Pregnancy and breastfeeding

Methadone and pregnancy

If recreational drugs are part of your life, getting help can really improve the outlook for you and your baby.

You can take methadone when you are pregnant, to help you stop taking heroin and having withdrawals. You will have a special care plan and will also need extra monitoring from your doctor, midwife or key worker.

If you become pregnant while taking methadone, speak to your doctor or prescriber. You may need to have more appointments. This is to make sure that the dose you take is right for you. Sometimes your dose may need to be adjusted as your pregnancy progresses.

If you take methadone at the end of pregnancy, your baby may be born dependent on methadone. Your midwife will check your baby for any withdrawal symptoms. They can be treated in hospital if they need it.

Methadone and breastfeeding

Talk to your doctor, midwife or health visitor if you want to breastfeed while taking methadone. If your baby is healthy and you are stable on methadone, you will usually be able to breastfeed while continuing your treatment. It may also help reduce withdrawal symptoms in your baby.

Small amounts of methadone pass into breast milk. This has been linked to breathing problems and drowsiness in a few breastfed babies.

However, it’s important to keep taking your methadone, to help reduce your withdrawal symptoms and cravings. Breastfeeding will also benefit you and your baby.

If you decide to finish breastfeeding while taking methadone, it’s important not to stop suddenly. Your midwife, or health visitor, together with your prescriber can advise you how to wean your baby gradually.

Tell your midwife, health visitor or doctor immediately if you notice your baby is not feeding as well as usual, seems unusually sleepy or has difficulty breathing, or if you have any other concerns about your baby.

Non-urgent advice: Tell your doctor if you're:

  • trying to get pregnant
  • pregnant
  • breastfeeding

8. Cautions with other medicines

Some medicines and methadone can affect each other and increase the risk of side effects or overdose.


Do not take morphine, buprenorphine, codeine or any other opioids while taking methadone.

Tell your doctor before starting on methadone if you are taking:

  • medicines to help you sleep, such as temazepam
  • antidepressants (particularly monoamine oxidase inhibitors such as tranylcypromine, phenelzine and isocarboxazid)
  • medicines for anxiety or stress, such as lorazepam and diazepam
  • medicine for heart rhythm problems, such as amiodarone, verapamil, diltiazem
  • medicines to help you stop feeling or being sick, such as metoclopramide
  • medicines for infections, including fungal infections
  • medicines for HIV
  • medicines for epilepsy, such as phenytoin and carbamazepine

Taking methadone with painkillers

It's usually ok to take methadone with paracetamol, ibuprofen or aspirin.

Do not take methadone with painkillers that contain codeine. You will be more likely to get side effects and increase the risk of overdose.

Painkillers that contain codeine include co-codamol (codeine and paracetamol), Nurofen Plus (codeine and ibuprofen), co-codaprin (codeine and aspirin) and Solpadeine (codeine, paracetamol, ibuprofen and caffeine). Some migraine treatments and cough syrups also contain codeine. Always check the ingredients on the packaging.

Speak to a pharmacist or a doctor if you need any advice about pain relief while taking methadone.

Mixing methadone with herbal remedies and supplements

There may be a problem taking St John's wort with methadone. It can stop the methadone from reducing your withdrawal symptoms properly.

It's not possible to say whether other herbal medicines and supplements are safe to take with methadone. They're not tested in the same way as pharmacy and prescription medicines. They're generally not tested for the effect they have on other medicines.

Important: Medicine safety

Tell your doctor or pharmacist if you're taking any other medicines, including herbal medicines, vitamins or supplements.

9. Common questions about methadone

How does methadone work?

Methadone is a man-made opioid, similar to morphine or heroin.

Methadone will cause feelings of relaxation and reduce pain, but it will not give you the same high or euphoric feeling as heroin.

It works in treating heroin addiction by reducing the withdrawal symptoms and cravings. It is long acting and this means it stays in your body a lot longer than morphine and heroin.

How long does methadone take to work?

Methadone reaches its peak effect after 2 hours. When you first start your treatment, and you’re on a low dose, the effects may only last for a few hours.

Your starting dose will be increased gradually each day, as needed, until you no longer have withdrawal symptoms. Once your dose is stabilised, a single methadone dose will work for 24 to 36 hours.

How long will I take methadone for?

You will stay on methadone until you decide to come off it. When you are ready to do this, your key worker will help you do this reduce your dose of methadone gradually.

Weaning off heroin and methadone completely, as part of a detox programme, normally takes at least 12 weeks.

If you are taking methadone for maintenance therapy, you will keep taking methadone long term, as a substitute for heroin.

Can I take methadone for a long time?

Yes. If you have a maintenance therapy treatment plan, you can take methadone long term as a substitute for heroin.

How will methadone make me feel?

Methadone slows down your body functions and reduces physical pain as well as feelings of anxiety.

It does not give you the same “high” or feeling of euphoria that you get with heroin.

Will I become dependent on methadone?

If you take it for a long time, it is possible to become physically and mentally dependent on methadone.

If you are worried about becoming dependent on methadone, speak to your doctor or key worker. They can agree on a treatment plan with you to try to gradually reduce your dose of methadone.

How will I know if I'm dependent on it?

If you are dependent on methadone, you may get physical or psychological symptoms if you miss a dose, or when your dose is reduced too quickly.

Physical symptoms include feeling restless or anxious, runny nose, sweating, feeling or being sick, diarrhoea and muscle cramps.

Psychological symptoms include craving heroin, or feeling you need to increase your dose of methadone.

What will happen if I stop taking methadone?

If you want to stop taking methadone, you will need to make a new treatment plan. Your GP or key worker will help you to reduce your dose very gradually. This is to help prevent withdrawal symptoms.

If you stop taking your methadone suddenly, you will have withdrawal symptoms. These include feeling restless or anxious, runny nose, sweating, feeling or being sick, diarrhoea and muscle cramps.

Can I drink alcohol with methadone?

It’s best to avoid alcohol while taking methadone.

Alcohol will make you feel sleepier and can increase the risk of serious side effects when taking methadone.

Is there any food or drink I need to avoid?

Eating grapefruit and drinking grapefruit juice can affect how your methadone works. It can make side effects worse

Apart from avoiding grapefruit, and reducing alcohol, you can eat and drink normally while taking methadone.

Are there other treatments for heroin addiction?

Other medicines used to treat heroin addiction are buprenorphine, and buprenorphine with naloxone.

Buprenorphine works in a different way to methadone and other opioids and gives you less of a “high”. This means you are less likely to have withdrawal effects or become dependent on it. It's a type of opioid called a partial agonist.


These are drugs that work on certain receptors in your brain and give you the full opioid effect ("high"). Full agonists include heroin, oxycodone and morphine.

Partial agonists

These also work on the opioid receptors in your brain, but to a much lesser extent, so you get less of a high.


These attach themselves to your opioid receptors and block the effect of opioid drugs. Naloxone is an antagonist and is sometimes used to reverse a heroin or methadone overdose.

Will methadone affect my contraception?

Methadone does not affect any type of contraception including the combined pill or emergency contraception.

But if methadone makes you sick (vomit), your contraceptive pills may not protect you from pregnancy.

If this happens, follow the instructions in the leaflet that comes with your contraceptive pills.

Find out what to do if you're on the pill and you're sick or have diarrhoea.

Will methadone affect my fertility?

There's no clear evidence to suggest that taking methadone will reduce fertility in women or men.

However, speak to your key worker or GP if you're trying to get pregnant. They may want to review your treatment.

Can I drive or ride a bike?

Do not drive while taking methadone, until your doctor tells you it is safe to do so. Your driving licence may be suspended until you are on a stable dose of methadone. You must tell the DVLA if you have used illegal drugs or misused prescription medicines.

Do not drive a car, ride a bike or operate machinery if methadone makes you sleepy, gives you blurred vision or makes you feel dizzy, clumsy or unable to concentrate or make decisions. Wait until you feel OK and your vision is clear.

It's an offence to drive a car if your ability to drive safely is affected. It's your responsibility to decide if it's safe to drive. If you're in any doubt, do not drive.

Even if your ability to drive is not affected, the police have the right to request a saliva sample to check how much methadone is in your body. For more information on the law on drugs and driving, visit GOV.UK.

Talk to your doctor, a pharmacist or your key worker if you're unsure whether it's safe for you to drive while using methadone.