More patients with opioid use disorder (OUD) are turning to extended-release buprenorphine to treat their substance use than ever before.

However, prescription use of non-extended release formulations has declined, according to a Massachusetts-focused study published in JAMA Network Open.

Throughout the state, men were also more likely to be prescribed the extended-release version than women.

While researchers found that this may suggest an increase in access and acceptability of the medication overall—at least for patients in Massachusetts—a report from the U.S. Department of Health and Human Services Office of Inspector General found that among some groups, lower percentages of patients who have OUDs are receiving these prescriptions. This points to issues with access.

“There are multiple drivers for the shift in buprenorphine extended-release (ER) injectable formulation use. Among these drivers include adverse effects with sublingual (SL) administration; most commonly reported being nausea, poor taste of available SL products, difficulty dissolving and increased risk and reports of dental caries,” Becky Hoss, a senior substance related disorder pharmacist at UC Davis Health and associate professor at the University of California San Francisco School of Pharmacy who was not involved in the study told Behavioral Health Business. “Injectable ER formulations are helpful for patients who may be facing housing insecurity.”

A decline in the use of sublingual formulations—or dissolvable tablets typically taken daily—is also likely due to a range of barriers beyond side effects, she said. For instance, there is an increase in barriers to access of SL formulations at retail pharmacies, which also include stigma and a lack of information around the sublingual formulations. Excessive paperwork for controlled substances and limited or restrictive pharmacy inventory also contribute, Hoss noted.

Data from the OIG report indicates that only 40% of Medicare enrollees who are prescribed buprenorphine in any form continue with regular treatment for 6 months. Adherence to continuous treatment for individuals with OUDs is critical for positive outcomes.

However, another study found that increased use of extended-release formulations of the medication generally leads to better adherence and ultimately, more positive patient recovery outcomes. While any form of buprenorphine can cut overdose mortality rates by nearly 60%, the “extended-release injected formulation may provide an advantage,” at least when it comes to some opioids like fentanyl, a 2024 JAMA study revealed.

The number of opioid deaths per year has been around six times higher than the mortality level observed at the turn of the century in 1999. This is true even with buprenorphine medications getting approved for the treatment of OUDs back in 2002.

“The rise in extended-release buprenorphine patients signals increasing access and a willingness to adopt this treatment option among increasing numbers of people with OUD, but the unanticipated decrease in non-extended-release buprenorphine patients raises concerns,” researchers wrote of these latest findings in the Massachusetts study.

Federal Supply Schedule data shows that the monthly cost difference between non-extended-release and extended-release forms of the medication can range from around $196 for transmucosal buprenorphine to $1136 for extended-release buprenorphine.

With disparities in medication adherence largely among younger adults and women, Hoss said “utilizing closed loop health systems, open communication between provider, pharmacy and patient, increasing provider/pharmacist curiosity and flexibility are all useful,” adding that factors like “insurance formulary expansion, clinical decision support tools/guidelines and pharmacy technician support” could also help improve medication engagement and remove some barriers.

Ultimately, while the Massachusetts study claims to be the “first to examine extended-release buprenorphine and non-extended-release buprenorphine dispensing trends” outside of a clinical trial, researchers also point out that the noted trends in a possible increase of access and acceptability of the extended-release formulation of the medication may not be extrapolated beyond the state.

They also point out that “underreporting of buprenorphine patients and prescriptions is possible,” something underscored by the latest OIG report as well, which found that fewer than one in five Medicare patients with a substance use disorder (SUD) receive medications like buprenorphine for treatment, despite a growth in prescriptions for it.

If access and acceptability truly are on the rise for extended-release buprenorphine, patient adherence is a likely trend to follow.