Methadone is most commonly known as a medical treatment for heroin addiction. It is normally found as a swallowable liquid but also comes in injectable and tablet form. The effects are less potent than heroin but still offer an abscence of pain, some euphoria and a sense of contentment. When used to treat heroin or smack addiction it is useful for allowing users to stabilise while they work on emotional and lifestyle changes. However it is often abused as it does still have addictive properties, and it is not uncommon for former heroin addicts to progress to methadone addiction. Methadone causes a range of side effects including dry mouth, drowsiness, skin rashes, constipation and an inability to urinate. Long term use can cause breathing problems, comas and death.