Methadone is a long-acting synthetic opioid agonist medication that can prevent withdrawal symptoms and reduce craving in opioid-addicted individuals. It can also block the effects of illicit opioids. It has a long history of use in treatment of opioid dependence in adults and is taken orally. Methadone maintenance treatment is available in all but three States through specially licensed opioid treatment programs or methadone maintenance programs.