What clinicians need to know about treating opioid use disorder

Adverse effects. Some of the adverse events reported during treatment with buprenorphine include fever, back pain, nausea, cough, sedation, difficulty with urination, and constipation. Respiratory depression is a less common effect of buprenorphine, compared with full opioid agonists, because of the medication’s mechanism of action as a partial agonist.⁴⁸ As a result, buprenorphine has been shown to have a lower risk of fatal overdose than methadone.⁴⁹ Studies have shown buprenorphine to be more likely than methadone to reduce neonatal abstinence syndromes.⁵⁰

NaltrexoneNaltrexone is an opioid antagonist and is an option to promote relapse prevention. Because of its antagonist properties, naltrexone treatment should always start after opioid detoxification because it can potentiate immediate withdrawal symptoms. Naltrexone is available in oral and long-acting formulations, the latter of which may be considered in patients who have difficulty with adherence.³⁷

Oral naltrexone is taken as a single 50 mg-tablet once daily, whereas dosing for long-acting naltrexone in injectable and implantable formulations varies. These long-acting naltrexone formulations typically are administered monthly. Some of the adverse events reported during treatment with naltrexone are nausea, liver damage, and injection site pain.⁵¹

Buprenorphine/naloxoneBecause of buprenorphine’s agonist effects, it has a relatively high abuse potential compared with other opioids.⁵² Naloxone, on the other hand, is an opioid antagonist and is poorly absorbed when given orally and is associated with withdrawal symptoms if used intravenously. Therefore, naloxone is added to buprenorphine to decrease the likelihood of abuse when both are used as a combination product.⁵³

Buprenorphine is combined with naloxone in a ratio of 4:1. Induction begins by using a 2 mg/0.5 mg tablet with dosage titration until symptoms abate. A combination of buprenorphine and naloxone also is available in film and tablet formulations. Patients must abstain from other opioids for at least 24 hours before initiating buprenorphine/naloxone treatment to prevent the precipitation of withdrawal symptoms.