It is still occasionally used for pain relief. Methadone is now primarily used today for the treatment of narcotic addiction. Methadone's effects can last up to 24 hours, thereby permitting administration only once a day in heroin detoxification and maintenance programs. Tablets and injectable ampoules are sometimes prescribed, and like many other medicines some of these prescribed drugs are diverted and become available illegally. Methadone generally entails the entire spectrum of opioid side effects, including the development of tolerance and physical and psychological dependence.
Respiratory depressions are dangerous.
The released histamines can cause hypotension or bronchospasms. Some methadone users feel sick when they first use the drug. If you are a woman using methadone you may not have regular periods - but you are still able to conceive. In 15 yrs of heroin addiction, I've kicked 3 times, 'cold-turkey'. In 10 years on methadone I've never kicked methadone.