Methadone has a sedative effect, reduces drive and has an influence on sleep behaviour. The dream and deep sleep phases are reduced. Physical effects may include sweating, a feeling of heaviness in the arms and legs, weight gain, dry mouth and reddening of the face and neck. Difficulty concentrating, reduced alertness and depression may also occur. As with all other opioids, there is a constriction of the pupils, slower breathing, lower pulse rate, suppression of irritable cough, constipation, loss of libido, dizziness and insensitivity to pain. The effect of insensitivity to pain disappears with the development of tolerance.

A methadone overdose, like a heroin overdose, leads to respiratory and circulatory arrest. In this case, the affected person must not be left alone and the emergency services must be called immediately and resuscitation measures started if necessary.

Methadone is administered orally, i.e. by mouth. You can find more information on how to take it under Risk Reduction. In contrast to heroin, the effect sets in more slowly, after around 30 minutes and less intensively, so there is no so-called "kick" or "rush". It takes an average of 25 hours for methadone to be broken down in the liver and excreted via the kidneys, i.e. methadone has a very long-lasting effect. For this reason, it is used as a substitution drug.

Long-term methadone use can lead to physical and psychological dependence. In contrast to heroin, methadone has a weaker effect, but the withdrawal symptoms are stronger and last longer. Taking methadone can lead to the absence of menstruation.

Liver disease (unless under medical supervision), as methadone is excreted via the liver and kidneys and can place additional strain on them.

Methadone acts on those receptors that are also stimulated by other opioids such as heroin. The strong effect of methadone on these receptors greatly reduces the effect of other opioids. This means that mainly the effects of methadone and not those of the other opioids are perceived. Therefore, if heroin is taken at the same time, it can hardly have any effect at all. However, if heroin is administered in an unusually high dose in order to achieve an effect despite the methadone, the risk of respiratory paralysis increases.

The simultaneous consumption of methadone with alcohol or other downers, such as tranquillisers (Valium, Rohypnol) or GHB, increases the effects of both substances, which can cause nausea, vomiting and fainting. In addition to the risk of overdose, both substances inhibit breathing, which in turn harbours the risk of respiratory arrest.

The combination of cocaine and opioids has the opposite effect on the body. This can result in shortness of breath and cardiovascular failure.

• As a substitution drug, methadone is administered in liquid form with syrup. If the substitution substance originally intended for oral administration is injected, this can lead to vein irritation and inflammation, as well as to inflammation of the heart valves due to the introduction of bacteria and fungi.
• As the effects of methadone take effect very slowly and last for a very long time, there is a risk, especially with inexperienced users, of consuming more or taking other tranquillisers in order to achieve a faster effect, which can easily lead to an overdose.

Methadone belongs to the group of synthetic opioid agonists. An agonist is a substance that produces its effect by binding to a receptor. The effect of methadone is similar to that of morphine. Unlike other medicines, methadone (in powder form) is mixed by the pharmacist himself by adding distilled water and syrup to the basic substance (methadone hydrochloride). The basic substance is the so-called "racemate" (a 50:50 mixture of L- and D-methadone). In Germany, only L-methadone (L-polamidone) is used, without D-methadone, which is ineffective at the opioid receptor and therefore has twice the effect (conversion 1:2). Methadone acts on an opiate receptor, the so-called µ-receptor, and thus causes the analgesic and respiratory depressant effect, the cough suppression, the constipation and the euphoric effects.

Methadone is a synthetic substance that was developed during the Second World War as a drug for pain therapy. The first fully synthesised opioids were pethidine (1938) and methadone (1945), which were produced at Farbwerke Hoechst by Otto Schaumann, a professor of pharmacognosy (drug science). After the war, this factory was under American control. The first clinical trials began in 1947 and the American pharmaceutical company Eli-Lilly coined the name Dolophine for methadone, a combination of the Latin word dolor (pain) and the French word fin (end). Today, methadone is mainly used as a substitution drug, but it is also used as a painkiller (heptadone).

It was first used in 1968 by doctors Nyswander and Dole as a means of substitution treatment for heroin addicts. Substitution means that long-term opioid users are prescribed a substance that is similar to heroin. By prescribing this substance, the person concerned can legally obtain a substitution drug under medical supervision, which is intended to reduce criminality and health risks that arise, for example, from intravenous consumption. It can also lead to stabilisation in the psychosocial area. This means that those affected can return to work and their housing and living situation can improve. Since 1987, the decree on oral substitution treatment has allowed methadone to be used as a substitution drug. In 1998, substitution treatment was enshrined in law when the Narcotic Substances Act came into force. Anyone who takes methadone without a doctor's prescription is not only liable to prosecution under the Narcotic Drugs Act and the Medicinal Products Act, but is also taking a health risk by misusing it.

As a medicine, methadone is subject to the Medicines Act and requires a doctor's prescription. Anyone who simply passes on or sells methadone is in breach of the Medicines Act, even if the medication was originally prescribed by a doctor.

Furthermore, methadone is subject to the Narcotic Substances Act and its penal provisions for psychotropic substances. In particular, the acquisition, possession, production, import and export, transfer to and procurement for others (transfer, sale, etc.) of this substance is punishable by law and can result in fines and prison sentences. Misuse of methadone is a criminal offence under the Medicines Act and the Narcotics Act.