Medication-Assisted Treatment (Methadone)
Methadone is a synthetic pure mu opioid agonist with good oral bioavailability, and a long duration of action. Methadone prevents withdrawal symptoms and helps reduce drug cravings in opioid dependent individuals. It also blocks the euphoria produced by short acting opioids. This collection of attributes makes this drug an appropriate choice for opioid maintenance therapy.
Methadone was developed in Germany before the Second World War and was used as a substitute analgesic for morphine. Early research in the late 1940’s showed that it could also be used to treat withdrawal symptoms in heroin dependent individuals. In the early 1960s, Dole and Nyswander demonstrated the feasibility of using methadone as a maintenance medication although it was actually a Canadian researcher, Dr. Robert Halliday, who set up what may have been the first methadone maintenance treatment program in the world in British Colombia in 1963.
Methadone maintenance typically involves the daily oral administration of methadone over an extended period of time as a substitute for heroin or other short acting opioids to opioid dependent individuals. Once an individual has been stabilized on a dose of methadone, subsequent daily doses should not cause sedation, analgesia, or euphoria. Methadone is long acting; it can prevent the occurrence of withdrawal symptoms or cravings when a patient receives an optimal dose. This enables individuals to function normally and to perform mental and physical tasks without impairment. In sufficient doses, cross-tolerance to other opioids develops i.e. methadone “blocks” the euphoric effects of self-administered illicit opioids.
Numerous studies have shown that maintaining opioid dependent individuals on methadone has many benefits including: (1) reduced illicit drug usage, (2) improved self status as a result of access to treatment, (3) decreased transmission of HIV and HCV, HBV, (4) decreased illegal activity, (5) increased employment, (6) decreased cost to society and (7) decreased mortality. Further, one of the indirect benefits of methadone treatment is that patients come into contact with other services—counseling and vocational services.