A clinical trial supported by the National Institutes of Health (NIH) has found that a weekly injectable, extended-release formulation of Buprenorphine is more effective in treating Opioid Use Disorder (OUD) during pregnancy than the commonly used daily sublingual version.

The study, published in JAMA Internal Medicine, revealed that pregnant patients receiving weekly injections showed significantly higher rates of abstinence from illicit opioids. Additionally, serious adverse events were reported less frequently among those receiving the extended-release treatment.

Experts highlighted the clinical importance of the findings amid the ongoing opioid crisis. Nora D. Volkow, Director of the National Institute on Drug Abuse (NIDA), noted that the injectable formulation not only proved safe during pregnancy but also delivered improved treatment outcomes compared to sublingual buprenorphine.

Untreated opioid use disorder during pregnancy poses severe risks, including overdose in mothers and conditions such as Neonatal Opioid Withdrawal Syndrome (NOWS) in newborns. While sublingual buprenorphine remains an effective standard treatment, it is associated with challenges such as poor adherence, misuse potential and fluctuating drug levels that may not fully control cravings.

To evaluate an alternative approach, researchers conducted a multicenter randomised clinical trial involving 140 pregnant participants. The study compared weekly subcutaneous injections of extended-release buprenorphine with daily sublingual administration (with or without naloxone). Postpartum participants not breastfeeding had the option to switch to a monthly injectable dose.

The trial was conducted under the National Institute on Drug Abuse Clinical Trials Network as part of the NIH HEAL Initiative, marking the first randomised study assessing extended-release buprenorphine use during pregnancy and postpartum.

Findings showed that patients receiving the injectable formulation had significantly higher abstinence rates during pregnancy and comparable outcomes postpartum. While non-serious adverse events were similar across both groups, serious maternal complications were less frequent in the extended-release group. Importantly, outcomes related to neonatal opioid withdrawal syndrome did not differ significantly between the two treatment methods.

Lead investigator John Winhusen from the University of Cincinnati College of Medicine stated that the results offer immediate clinical relevance, demonstrating that longer-acting medication can safely and more effectively support recovery among pregnant patients.

The National Institute on Drug Abuse, a key arm of the NIH under the U.S. Department of Health and Human Services, continues to support research aimed at improving treatment strategies, informing policy, and advancing the science of addiction.