Methadone maintenance treatment significantly decreases the rate of HIV infection for those patients participating in MMT programs. At proper dosing, methadone usually reduces the appetite for and need to take opiates, and also block the euphoric effects of them, thus greatly reducing the motivation of patients to use.
Methadone offers patients the freedom from active addiction [...]

 
In case of methadone withdrawal symptoms are generally slightly less severe than those of morphine or heroin at equivalent doses but are significantly more prolonged. Methadone withdrawal symptoms can last for several weeks or more. At high maintenance doses, sudden cessation of therapy can result in withdrawal symptoms described as “the worst withdrawal imaginable,” lasting [...]

 
Unfortunately, as many other prescription drugs, methadone has also several adverse effects like thrombus, hypo ventilation, constipation, increased sweating, heat intolerance, chronic fatigue, sleepiness and exhaustion, constricted pupils, nausea, low blood pressure, hallucination, headache, vomiting, cardiac arrhythmia, anorexia, etc.
Among the undesired side effects were reported and weight gain, gynecomastia, stomach pains, dry mouth, perspiration, flushing, [...]

 
The most common route of administration at a methadone clinic is in a racemic oral solution, though in Germany, only the (R)-methadone enantiomer has traditionally been used, as it is responsible for most of the desired opioid effects. This is becoming less common due to the higher production costs.
Methadone is available in traditional pill, sublingual [...]

 
Methadone acts by binding to the µ-opioid receptor, but also has some affinity for the NMDA ionotropic glutamate receptor. It is metabolized by the enzymes CYP3A4, CYP2B6 and CYP2D6, with great variability between individuals. Its main route of administration is oral. Adverse effects include hypo ventilation, constipation and meiosis, in addition to tolerance, dependence and [...]