In California, where overdose deaths have been rising for years, addiction experts say administering a month’s worth of anti-addiction medication in a single injection holds great potential, particularly for people without housing or who struggle with other forms of instability. Yet despite its promise, the use of injectable buprenorphine remains fairly limited, especially compared with other forms of addiction medication. Researchers have yet to publish studies comparing different ways to administer buprenorphine.

Buprenorphine, one of three medications approved in the U.S. to treat opioid use disorder, works by binding to opioid receptors in the brain and reducing cravings and withdrawal symptoms. And because it occupies those receptor sites, buprenorphine keeps other opioids from binding and ensures that if a patient takes a high dose of a drug like heroin or fentanyl, they are less likely to overdose. Patients often stay on buprenorphine for years.

If Dr. Andrew Herring, who practices at an addiction clinic at Highland Hospital in the heart of Oakland, prescribes a supply of buprenorphine as a tablet or film that is placed under the tongue, the patient must commit to taking the medication at least once a day, and many fall out of treatment. He said this is especially true for his patients experiencing homelessness and those who also use methamphetamine.

Oral forms of buprenorphine have been available to treat addiction since 2002 and can be purchased as a generic for less than $100 a month. Injectable buprenorphine, sold under the brand name Sublocade, received FDA approval in 2017. It has a hefty list price of $1,829.05 for a monthly injection.

Still, addiction experts say, Sublocade use remains limited because of the regulatory hurdles required to dispense it.

Providers must register with the U.S. Drug Enforcement Administration and obtain a waiver to prescribe buprenorphine because it’s considered a controlled substance. In addition, clinics must complete an FDA safety certification program to dispense the medication. And Sublocade can be ordered only by a specialty pharmacy, which must also pass the FDA program.

“At many hospitals, that will mean either a delay in getting this medication on our shelves or just opting out,” said Dr. Rais Vohra, regional director for the California Bridge Network, a state-funded program that supports hospitals in offering treatment for substance use disorders, including Herring’s clinic.

Vohra said Community Regional Medical Center in Fresno, where he works as an emergency physician, is still looking through the documentation requirements to see if the hospital’s pharmacy can distribute the medication — which would make it one of the few Central Valley providers to do so.

Oral buprenorphine, by contrast, is a simple prescription that most local drugstores keep in stock.

“All the hoops that clinicians and patients have to jump through to get this medication is crazy. We don’t do that for any other disease,” said Dr. Hannah Snyder, who runs the addiction clinic at Zuckerberg San Francisco General Hospital across the bay.

“The most important question isn’t whether long-acting injectable bupenorphine is a better solution than sublingual buprenorphine for opioid use disorder,” said Dr. Michael Ostacher, a professor at Stanford University School of Medicine, who is comparing injectable and oral versions of buprenorphine through Veterans Affairs. “The bigger question is how we increase access to treatment for all people who need [the medication].”

California’s Medicaid program does not require prior authorization but providing Sublocade is still a challenge. At the Placerville clinic supported by the California Bridge Network, Dr. Juliet La Mers, the director, said a quarter of her buprenorphine patients get injections. Still, they often wait two weeks before Sublocade arrives from the specialty pharmacy.

In states where Medicaid plans may still require prior authorization, waits for Sublocade can stretch into months. Across the border at the Northern Nevada Hopes clinic in Reno, Nevada, for example, Dr. Taylor Tomlinson said she tells patients that between battles for coverage and pharmacy delays, they might have to wait two months for an injection.