Medication Treatment of Opioid Use Disorder.

Opioid use disorder (OUD) is a chronic, relapsing condition, often associated with legal, interpersonal, and employment problems. Medications demonstrated to be effective for OUD are methadone (a full opioid agonist), buprenorphine (a partial agonist), and naltrexone (an opioid antagonist). Methadone and buprenorphine act by suppressing opioid withdrawal symptoms and attenuating the effects of other opioids. Naltrexone blocks the effects of opioid agonists. Oral methadone has the strongest evidence for effectiveness. Longer duration of treatment allows restoration of social connections and is associated with better outcomes. Treatments for OUD may be limited by poor adherence to treatment recommendations and by high rates of relapse and increased risk of overdose after leaving treatment. Treatment with methadone and buprenorphine has the additional risk of diversion and misuse of medication. New depot and implant formulations of buprenorphine and naltrexone have been developed to address issues of safety and problems of poor treatment adherence. For people with OUD who do not respond to these treatments, there is accumulating evidence for supervised injectable opioid treatment (prescribing pharmaceutical heroin). Another medication mode of minimizing risk of overdose is take-home naloxone. Naloxone is an opioid antagonist used to reverse opioid overdose, and take-home naloxone programs aim to prevent fatal overdose. All medication-assisted treatment is limited by lack of access and by stigma. In seeking to stem the rising toll from OUD, expanding access to approved treatment such as methadone, for which there remains the best evidence of efficacy, may be the most useful approach.