Common questions about methadone - Brand name: Physeptone

Methadone is an opioid medicine. Other opioids include codeine, morphine, fentanyl and oxycodone.

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

It works in treating heroin addiction by reducing the withdrawal symptoms and cravings. It's also long acting so it can stay in your body a lot longer than morphine and heroin.

Methadone takes around 2 hours to work. 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, as needed, until you no longer have withdrawal symptoms or heroin cravings. Once your body is used to the medicine, a single methadone dose will work for 24 to 36 hours.

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

It does not give you the same feeling that you get with heroin.

If you take methadone for a long time, it's possible to become dependent on it.

If you're worried about this, speak to your GP, prescriber or key worker. They can agree on a treatment plan with you to try to gradually reduce your dose of methadone.

If you're 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, a runny nose, sweating, feeling or being sick, diarrhoea and muscle cramps.

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

If you want to stop taking methadone, you'll need to make a new treatment plan. Your GP, prescriber 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'll have withdrawal symptoms. These include feeling restless or anxious, a runny nose, sweating, feeling or being sick, diarrhoea and muscle cramps.

Other medicines used to treat heroin dependence are buprenorphine, buprenorphine with naloxone, lofexidine and naltrexone.

Methadone does not stop any type of contraception from working, including the combined contraceptive pill, progestogen-only pill and 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 more:

• What to do if you're sick or have diarrhoea when taking the combined pill
• What to do if you're sick or have diarrhoea when taking the progestogen-only pill

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, cycle or use machinery or tools 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.

Talk to your doctor, a pharmacist or your key worker if you're unsure whether it's safe for you to drive while taking methadone. GOV.UK has more information on the law on drugs and driving.

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.

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

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