Methadone is a synthetic substance with pharmacological properties similar to morphine and heroin. Methadone is prescribed for patients with severe pain, such as those with serious injuries or those who have undergone major surgery. Methadone works in the brain to decrease the sensation of pain and to mute the emotional response to pain. It comes as tablets, dispersible tablets, liquid, and liquid concentrate. Patients take it every 3-4 hours for severe pain and every 6-8 hours for chronic pain. Since methadone can be as addictive as morphine and heroin, care must be taken to follow the doctor's instructions. Do not take a larger dose, or take it more frequently, or take it for longer than the doctor has prescribed. Methadone is one of the most difficult drugs to detox from since its effects are long-lasting and it is readily stored in the body's tissue.

Methadone is also used as a replacement-opiate therapy for opiate dependency. A legal dependency (methadone) is substituted for an illegal dependency (heroin). Methadone is available in government-approved drug treatment clinics and by prescription in some areas.