Monthly Injectable Buprenorphine Cuts Relapse Risk by Up to 8 Times, New Studies Show

Two new real-world studies published this week add compelling evidence that monthly injectable buprenorphine substantially outperforms other medication-assisted treatment approaches for opioid use disorder, reducing relapse risk by as much as eightfold while cutting serious infectious complications and emergency healthcare utilization.

The findings, announced May 20 by Indivior PLC and published in peer-reviewed journals, represent some of the largest retrospective analyses of extended-release buprenorphine since its FDA approval. Researchers examined insurance claims and electronic health records spanning thousands of patients, offering a window into how the monthly injection performs outside controlled clinical trial settings.

Dramatic Reduction in Return to Opioid Use

The first study, published in Drug and Alcohol Dependence Reports, analyzed 12-month adherence patterns among 3,400 patients receiving various forms of medication for opioid use disorder. Patients who remained adherent to monthly injectable buprenorphine were 3.5 to 8.1 times less likely to return to opioid use compared to those on other medication regimens—including both adherent and non-adherent patients taking daily oral buprenorphine or methadone.

The analysis identified several factors associated with higher relapse risk: younger age, male sex, Medicaid coverage, urban residence, comorbid alcohol or other substance use disorders, and limited prior engagement with buprenorphine before initiating the extended-release formulation. Skin infections also emerged as a risk marker, potentially signaling broader health instability or ongoing injection drug use.

"These findings emphasize the importance of proactively identifying patients at risk of treatment discontinuation," said Christian Heidbreder, Ph.D., Chief Scientific Officer at Indivior. "Sustained treatment with monthly injectable buprenorphine appears to provide protective benefits that extend beyond what we see with daily medication approaches."

62% Reduction in Bloodstream Infections

A second study in The Journal of Substance Use and Addiction Treatment compared infectious disease outcomes between 467 patients receiving monthly injectable buprenorphine and nearly 120,000 patients on daily oral formulations. The extended-release group demonstrated a 62% reduction in bacteremia incidence—bloodstream infections that can become life-threatening and often require hospitalization.

The protective effect likely stems from eliminating the daily medication-taking ritual that can trigger cravings and relapse cycles. Patients receiving monthly injections also experienced dramatically lower healthcare utilization across all categories: 56% fewer inpatient hospitalizations, 22% fewer emergency department visits, 21% fewer outpatient appointments, and 77% fewer visits related to sexually transmitted infections.

"By improving continuity of care, monthly injectable buprenorphine has the potential to reduce costly acute care crises and support meaningful, long-term recovery," said Ann Wheeler, PharmD, Vice President of Medical Affairs at Indivior.

Real-World Advantages Over Daily Dosing

The research arrives as addiction medicine increasingly recognizes that medication adherence—not just prescription—determines outcomes. Daily oral buprenorphine requires patients to maintain consistent routines, secure stable housing for medication storage, and navigate pharmacy visits that can become relapse triggers. A single missed dose can precipitate withdrawal, driving some patients back to illicit opioid use.

Monthly injections eliminate many of these friction points. Administered subcutaneously by healthcare providers, the formulation forms a solid depot that slowly releases buprenorphine over four weeks. Patients cannot divert or misuse the medication, addressing concerns that have historically limited buprenorphine access. The approach also removes the stigma of daily pharmacy visits for a controlled substance.

Implications for Treatment Access

Despite these advantages, monthly injectable buprenorphine remains underutilized. Cost barriers persist—though the Affordable Care Act mandates coverage for medication-assisted treatment, prior authorization requirements and formulary restrictions delay access. Many community health centers lack the refrigeration and clinical infrastructure to administer injections. Workforce shortages in addiction medicine mean fewer providers are trained to initiate extended-release formulations.

The new data may shift these dynamics. The 62% reduction in bloodstream infections carries particular weight given rising concern about infectious disease complications among people who use drugs. Endocarditis, sepsis, and soft tissue infections now drive substantial hospitalization costs—expenditures that could be partially avoided through broader adoption of monthly injections.

Study Limitations

Both analyses relied on retrospective claims data, which cannot establish causation or capture care received outside the studied networks. The COVID-19 pandemic disrupted treatment patterns during portions of the study period, potentially affecting adherence measurements. The extended-release cohort was smaller than the oral buprenorphine comparison group, though still substantial at 467 patients for the infectious disease analysis.

Additionally, the studies were funded by Indivior, the manufacturer of Sublocade, raising standard concerns about industry-sponsored research. However, the peer-review process and use of established medical claims databases provide some independent validation.

Looking Forward

With overdose deaths declining nationally but remaining near 70,000 annually, tools that improve treatment retention carry enormous public health significance. The 3.5 to 8.1 times reduction in relapse risk suggests monthly injectable buprenorphine could prevent thousands of return-to-use events if scaled appropriately.

For clinicians, the findings support considering extended-release formulations earlier in treatment—particularly for patients with risk factors like housing instability, comorbid substance use, or histories of treatment discontinuation. For policymakers, the healthcare utilization data strengthen the economic case for removing coverage barriers.

"Medication for opioid use disorder saves lives," Wheeler noted. "These studies help us understand which delivery methods produce the best outcomes—and why."

As the field moves toward personalized addiction medicine, the research underscores a fundamental principle: how treatment is delivered matters as much as what is prescribed.