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.

• 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.

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

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.

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.

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.

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.

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