There are three federally approved medications to treat opioid use disorder, and all should be used in conjunction with counseling: methadone, buprenorphine, and extended release injectable naltrexone. SAMHSA’s TIP 43 states that “when methadone is administered daily in steady oral doses, its level in blood should maintain a 24-hour asymptomatic state, without episodes of overmedication or withdrawal” (SAMHSA, 2005). When methadone maintenance treatment is provided to a patient through one of 1,500 federally approved opioid treatment programs by knowledgeable and trained personnel, the medication stabilizes the patient and does not produce euphoric effects (a “high”). It also does not impair cognitive or motor functioning or result in over-sedation (“nodding off”) (NIDA, 2009).
Methadone has a gradual onset of action and produces stable levels of the drug in the brain; as a result, patients maintained on this medication do not experience a rush, while they also markedly reduce their desire to use opioids. If an individual treated with methadone or buprenorphine tries to take an opioid such as heroin, the euphoric effects are usually dampened or suppressed. Patients undergoing maintenance treatment do not experience the physiological or behavioral abnormalities from rapid fluctuations in drug levels associated with heroin use (NIDA, 2009).
Buprenorphine is used to treat opioid use disorder in the United States in both pill and sublingual film preparations through federally certified Drug Addiction Treatment Act of 2000 (DATA) physician/NP/PA practices or as another medication in the opioid treatment program. Longer acting buprenorphine implants are also being used to treat this disorder.
As a partial agonist, rather than a full agonist such as methadone or morphine, buprenorphine has pharmacological properties that are similar to but different than those of methadone. It has a therapeutic limit for most of the effects produced by opioid drugs, such as analgesia and respiratory depression. This makes buprenorphine safer, in terms of respiratory depression in case of an overdose but also may limit its efficacy for some patients” (NDCI, 2002).
When either methadone or buprenorphine maintained patients show signs of sedation, it is usually related to the use of alcohol and/or other drugs (such as benzodiazepine) beyond the use of methadone and buprenorphine. Patients in medication-assisted treatment for opioid addiction are admitted to treatment with co-occurring alcohol and other drug use.
Naltrexone is the third medication and is available both in pill and injectable formulation. SAMHSA describes naltrexone in TIP 43 as—
…a highly effective opioid antagonist that tightly binds to new opiate receptors. Because it has a higher affinity for these receptors than has heroin, morphine, or methadone, naltrexone displaces those drugs from receptors and blocks their effects. It can, therefore, precipitate withdrawal in patients who have not been abstinent from short acting opioids for at least seven days, and have not been abstinent from long acting ones, such as methadone, for at least ten days (SAMHSA, 2005).
The benefit of the injectable naltrexone formulation is that it is administered on a monthly basis, is not subject to diversion and it does not result in any dependence.
All three federally approved medications should be considered in treating opioid use disorder in the United States. Deciding on the appropriate medication is a matter of clinical discretion, taking into consideration the relevant medical standards and patient choice. People who are not addiction specialists—including judges, probation, and other justice personnel—do not have the expertise to make these medical decisions, just as they do not have the expertise to make other health-related decisions for individuals under their supervision.
When exercising medical judgment, addiction specialists generally consider certain principles. Typically, opioid-addicted individuals, who have not used opioids for a long period of time are more appropriate for use of buprenorphine or naltrexone products. For patients using opioids for a longer period of time, whether prescription or heroin, methadone is preferred because of the patients’ higher opioid tolerance.
Extended release injectable naltrexone can be effective with different populations through general medical practice settings. A physician or medical practitioner does not require a special license to use extended release injectable naltrexone, unlike methadone, which may only be dispensed through a registered Opioid Treatment Program, and buprenorphine products, which may only be prescribed by trained certified physicians/NP/PA in practice settings or opioid treatment programs. Extended release injectable naltrexone may also be used in effective relapse prevention strategies when the patient or treatment provider decides to taper the patient away from the use of methadone maintenance or buprenorphine maintenance.
Research shows that when treating SUDs, a combination of medication and behavioral therapies is the most effective. Behavioral therapies help patients engage in the treatment process, modify their attitudes and behaviors related to drug and alcohol abuse, and increase healthy life skills. These treatments can also enhance the effectiveness of medications and help people stay in treatment longer. Treatment programs that combine pharmacological and behavioral therapy services increase the likelihood of cessation relative to programs without these services. (CMS/SAMHSA/CDC/NIH-NIDA/NIH-NIAAA/Bullentin/July, 2014)
 DATA 2000 permits qualified physicians to obtain a waiver from the separate registration requirements of the Narcotic Addict Treatment Act to treat opioid use disorder with medications that have been specifically approved by the Food and Drug Administration for that indication.