Methadone is suitable for the treatment of severe pain. It can be used alone or in low doses as a breakthrough medication. In comparison with morphine it has the advantages of a longer-lasting effect and a better availability after oral administration. Mostly known in breaking the addiction of heroin addicts by providing them enough relief to "get the monkey off their backs."
Side Effects: 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. Other symptoms are: constipation, nausea or vomiting, sedation, vertigo and edema. Euphoria is considered a positive effect in the context of methadone programs (reduced craving for illegal substances).
Interactions: Enzyme inducers such as phenytoin and rifampicin can reduce the effect of methadone so significantly that withdrawal symptoms may occur. Other central nervous system depressors (e.g. alcohol), maybe even enzyme inhibitors, reinforce the central sedative effect of methadone. Infomed Drug Guide