Substitution de l'héroïne par la méthadone

What is heroin addiction?

If you are addicted to heroin it means that you develop withdrawal symptoms within a day or so of the last dose. These symptoms are listed in the separate leaflet called Medicines for Drug Dependence. If you are addicted to heroin, you need a regular dose to feel 'normal'.

What is methadone?

Methadone is a drug that is similar to heroin, although it lasts a lot longer in the body. It can be prescribed. If you take methadone, you are unlikely to develop withdrawal symptoms if you stop heroin (or the withdrawal symptoms are much less severe). If you take methadone under supervision from a doctor instead of street heroin, you are:

• More likely to be able to get away from the street 'drug scene'.

• Likely to feel better in yourself.

• More likely to be able to get off drugs for good.

Who prescribes methadone, and when?

A typical plan

Most GPs will refer you to a community drug team to be assessed. Following assessment, a member of the community drug team will usually contact your GP quite quickly to recommend a dose of methadone and a plan for follow-up. Some GPs who are specially trained may assess some cases and prescribe without the need for referral.

Évaluation

This usually includes:

• Taking details of your health and social circumstances.

• Taking details of your past and current drug taking and whether methadone is needed or appropriate.

• An examination.

• A urine test (or a mouth swab test) to confirm the drugs you are taking.

• An assessment of what you think you need at this present time.

If you have been injecting drugs such as heroin, it is also common to advise:

• A blood test which includes testing for HIV, checking the health of your liver (liver function tests) and checking for hepatitis B and hepatitis C.

• Immunisation against hépatite A, hépatite B et tétanos (if not previously immunised).

• If appropriate, immunisation against hepatitis B for your partner and children.

• About the dangers of injecting, about the dangers of using shared needles and syringes and on other ways to reduce harm to yourself.

Starting off with methadone

Methadone is usually started some time after assessment when the results of the urine test are back. An initial dose is chosen. The aim is to prevent withdrawal symptoms. However, methadone can cause serious harm, or death, in overdose. Therefore, at first your doctor will prescribe a low-ish dose to 'play safe' and see you frequently to adjust the dose. Be patient, this early stage is very important. The initial dose is usually gradually increased to a regular maintenance dose. But note:

• Methadone takes 2-4 hours to reach its peak effect level in the blood. However, the time it takes to produce its maximum effect can vary from person to person.

• Methadone accumulates in your body. So, you will feel a greater effect of the drug over a few days even without increasing the dose.

• It may take a few weeks to get to the correct dose which prevents all withdrawal symptoms.

Try to accept that you may have some, or partial, withdrawal symptoms until the correct dose is found. The correct dose varies from person to person, depending on how much heroin you were using and how your body deals with (metabolises) the methadone. You should not take any street drugs or much alcohol when you are on methadone.

Maintenance and coming off ('detox')

Once established on a regular dose, most people stay on methadone for a long time or even long-term. This is called maintenance and helps you to keep off street drugs. Some people gradually reduce the dose and come off it. This is called detoxification, or 'detox'. However, it usually takes months and sometimes years before most people are ready to consider 'detox'. It is often safer to stay on methadone than to 'detox' before you are ready.

Taking methadone

Methadone is usually prescribed as a once-daily dose in liquid form. You will usually be asked to take it under the supervision of the pharmacist who dispenses the methadone to you. This means there can be no doubt about how much methadone you take at each dose. This supervision may be relaxed after a few months of you taking a regular maintenance dose.

Note importante: it is essential that you take the methadone regularly. If you miss three or more daily doses your body may lose its ability to break down the drug (tolerance). You can still continue with the withdrawal programme but you may need to start again with a lower dose.

Some other points about taking methadone

• You are more likely to succeed in staying off heroin if you have support and counselling during this difficult time. This may be from a local drug community team (or similar). Self-help groups or other agencies may also be of help. It is much harder to 'do it alone' - so do go for counselling and help if it is available in your area.

• Some prescribed medicines may interfere with methadone - for example, some used to treat la tuberculose (TB) et épilepsie. Tell the doctor who prescribes methadone if you are taking any other medicines. However, most prescribed medicines can be taken in the normal way.

• Other street drugs, tel que benzodiazépines ('benzos'), and alcohol, can affect methadone. It is best not to take any other drugs and not to drink too much alcohol.

• You will be asked to give a urine sample from time to time by your doctor.

• Conduite. If you use heroin, methadone or similar drugs, you should tell the DVLA. You are likely to be banned from driving. However, if you are on a supervised methadone programme, you may be allowed to drive again subject to an annual medical review.

• Grossesse. If you become pregnant you should not suddenly stop your methadone withdrawal programme. It is riskier to stop methadone suddenly in the first three months of pregnancy than to continue on your regular dose. Many women choose to withdraw from methadone during pregnancy and this is best done during the third to sixth month of pregnancy (the 'second trimester'). Your doctor will advise.

• Keep methadone and any other drugs out of reach of children.