"Medication-based treatment for opioid dependence consists of 2 distinct approaches: detoxification and maintenance.4 Detoxification involves the use of medications to bring a patient from an opioid-dependent to an opioid-free state. The medications used are designed to decrease withdrawal-related discomfort and complications. Maintenance therapy involves the substitution of an abused opioid such as heroin or narcotic analgesics, which are often used intravenously or intranasally several times a day, by a medically prescribed opioid such as methadone or buprenorphine that can be taken orally and administered once a day in combination with counseling."
O’Connor PG. Methods of Detoxification and Their Role in Treating Patients With Opioid Dependence. JAMA. 2005;294(8):961–963. doi:10.1001/jama.294.8.961