How Pharmacists Can Close the Opioid Addiction Care Gap

Pharmacists have a role to play in closing the care gap for people with opioid addictions, just as they have played a role in lowering the number of drug overdose deaths for the first time in 5 years.

Thus asserted Lawrence Y. Chang, PharmD, APh, BCACP, BC-ADM, CDCES at a presentation at the American Society for Health-systems Pharmacists Midyear 2025 Clinical Meeting and Exposition, held from December 7-11 in Las Vegas, Nevada. Chang and fellow presenters Damian Peterson, PharmD, APh, BCPP, BCPS, and Brian L. Erstad, PharmD, said that the innovation pharmacists can and should bring to their practices can help turn the tide in what has been a decades-long opioid crisis in the United States and around the world.

"Drug overdose deaths are a problem," Chang said. “In 2023 there were 107,000 drug overdose deaths, approximately 70% of which can be attributed to fentanyl.” Chang cited data from the Centers for Disease Control (CDC) stating that overdose deaths have fallen by roughly 34% since 2023 and are projected to reach their lowest levels since 2019, which he called "wonderful news. We haven't seen a drop like this in so long.

"But sustained efforts are certainly needed to maintain progress," Chang said without missing a beat, "because this is still not good enough."¹

The History of Opiate Use and the Impact of Fentanyl

Opioids have a long history of use, dating back to ancient Mesopotamia, where the Papaver somniferum, or opium poppy, was valued for its analgesic and sedative effects. At the start of the 19th century, 21-year-old Friedrich Wilhelm Adam Sertürner reported the analgesic and narcoleptic effects of a substance he himself had isolated from the poppy plant which he called morphine. It began to be developed and distributed by several sources in the developed world by the time British chemist C.R. Alder Wright began looking for a non-addictive alternative and instead discovered an even more addictive drug that became known as heroin in 1874.^2-4

By the early 20th century, doctors and politicians recognized that opium derivatives were highly addictive. President Woodrow Wilson signed the Harrison Narcotics Tax Act on December 17, 1914 (almost exactly 111 years before the writing of this article), which forbade use of opium poppy and coca plant derivatives except in a limited medical capacity.⁵

In the 1980s, a poorly researched article in Pain argued that opiates could be prescribed long-term with safety as a pain reliever. By the time Purdue Pharma introduced OxyContin in 1995, opioid use had been slowly growing for nearly a decade. Within 1 year the trickle became a flood, urged on by falsified and misleading assurances about low addiction risk, ushering in the modern opioid crisis.⁶

As prescription rates declined, opioid use shifted to illicit heroin and, in time, to fentanyl, which is now the leading cause of drug-related deaths in the US.

To illustrate how fundamentally fentanyl has changed opioid tolerance, Chang used the example of a patient who admits to smoking 1 gram of fentanyl per day. "The DEA released this report talking about the average federal purity for domestic samples," Chang said, "and they estimated purity to be about 19.7% in the illicit drug supply [of fentanyl]. If you take a gram of that and multiply that by 19.7%, that gives you about 197,000 micrograms (mcg) of fentanyl per day."

The bioavailability, or portion of a drug that enters the body in an active form and is thus available to be absorbed by the body and enter the bloodstream, of fentanyl via inhalation is about 12%, Chang said. Thus, the patient who smokes 1 gram of illicit fentanyl is actually absorbing 12% of 197,000 mcg, or 23,640 mcg, of pure fentanyl.

Chang compared this to the typical IV dose of fentanyl in a hospital setting, which is only 50 mcg. "So if you do the math, these patients are essentially getting a typical dose of fentanyl about 473 times a day, or once every 3 minutes," Chang said. "You can see how tolerant these patients can get now."

Chang said the chronic, long-term use of fentanyl also accumulates in the body and may remain here for up to 14 days even if use discontinues.¹

Opioid Receptors and Available Treatments for Opioid Use Disorder (OUD)

Chang reviewed the 3 types of opioid receptors: mu (μ), Delta (δ), and Kappa (𝜅). Most of the approved medications for opioid use disorder (MOUDs) target μ receptors, which cause the feeling of euphoria and high addiction potential for most illicit drugs, including opiates, and are strong analgesics. Conversely, 𝜅 receptors produce strong feelings of dysphoria and have only moderate analgesic qualities, especially compared to μ receptors. The two receptors can both cause respiratory depression, constipation, sedation, and physical dependence, though again the μ receptors produce much stronger effects in all these areas.

Chang, Peterson and Erstad were most intrigued by the effects associated with δ receptors, which are much more mild. They cause little or no euphoria or dysphoria, no sedative effects, and have little risk for physical dependence. However, they also do not work as effectively to suppress pain, excepting spinal pain; and they still reduce respiratory and GI activity, though not to the same level as μ receptors.

The FDA has approved 3 drugs to treat opioid use disorder, all of which Chang and his fellow presenters reviewed in detail with its effects, efficacy, and barriers.

Methadone, a full agonist, is especially effective for patients with severe opioid tolerance or chronic pain. "It works," Chang said simply. However, it must be dispensed at clinics, usually requiring daily visits. Chang said the travel burden, stigma, and punitive monitoring practices make methadone an imperfect option, however effective it may be.

Naltrexone is another option, and as a full opioid antagonist it reduces the effects of opioids.. However, it has one major barrier to beginning treatment: "Patients often have to be sober and abstinent for at least a week to even qualify" for it, Chang said, which is often an insurmountable challenge. The two approved formulations are in oral form at 50 mg once per day, which showed no benefit over placebo due to poor retention; and the extended-release injectable formulation of 380 mg once every 28 days. This formulation is 90% effective at increasing opioid abstinence compared with 35% abstinence in placebo groups, "but it also has low rates of retention, especially if patients are homeless," Chang said.

Buprenorphine was the primary focus of the presentation. "It's a wonderful drug," Chang said, citing its safety profile due to its limited effect on respiratory depression. "It's impossible to overdose on buprenorphine," he said. It also has a high binding affinity for opiates, which protects patients from overdose if they relapse.

Unique among the three treatment options, Chang said, buprenorphine can reverse opioid tolerance over time. It also is an effective painkiller, 25-50x more powerful than morphine, and as a partial agonist, can be administered in a doctor's office as soon as withdrawal symptoms begin. The exact waiting period depends on the type of opioid used; for long-acting opioids such as fentanyl, the waiting period is 48-72 hours.

Buprenorphine also has a greater variety of formulations and administration routes available for providers and patients. It may be taken sublingually, as an injection, as a patch, or as a buccal film.¹

Challenging Outdated Dose Limits

Chang urged the pharmacists in his audience to rethink buprenorphine dose ceilings, especially for patients with fentanyl addictions. Many pharmacies, he said, still enforce a maximum daily dose of 24 mg, but this is based on outdated information. New package inserts now say that while 24 mg is the maximum studied dose, higher doses "may have potential benefit." SAMHSA has long listed 32 mg as the maximum dose.

In reality, "[t]here is no maximum dose," Chang said. "When it comes to buprenorphine, we want to think about serum concentration, how much of the μ [receptors] [are] inside of the patient's body, because that correlates to opioid receptor occupancy."

Chang presented a graphic showing the relation of μ-opioid receptor occupancy (μORO) (0-100%) to buprenorphine serum concentration, measured in ng/mL. An analgesic effect was achieved at around 35% μORO; withdrawal suppression at about 50-60% μORO, which was achieved with ≥1 ng/mL.

"To achieve opioid blockade," Chang said, "to meet [and suppress] their cravings ... and to make sure that [the] other opioids acnnot really be effective, you need to ... achieve about 70-80% receptor occupancy."

This, he said, can usually be done with a buprenorphine serum concentration of 2-3 ng/mL. For patients with long-term or heavy use, or use of fentanyl, this serum concentration may need to be 4-5 ng/mL.¹

Long-acting monthly injectable buprenorphine were presented as a major breakthrough in achieving this concentration. "The injectable is one shot and done," Chang said. "It's better adherence. It's less diversion. ... It has less fluctuations in the peak and the trough, [and] the patient is not attached to taking something constantly." It also tapers off naturally, providing a good option for introducing other medications if those are preferable.

However, this formulation also has cons, including a shelf life of only 45 days, after which any unused doses must be thrown away, potentially wasting money. Patients also often report pain palpable subcutaneous deposits at the injection site, which can last weeks.

Perhaps the most striking data presented in the session came when Chang shared data from a 2021 systematic review of the mortality benefits of MOUD which showed that buprenorphine reduced mortality by 66%, besting methadone at 53%.

"The number needed to treat to prevent one death one year after overdose is 52. That' better than any medication out there, any aspirin, any atorvastatin," Chang said, before admitting the aspirin comment may have been an overstatement. "This has a profound mortality benefit in our patients. You could save lives with this." Yet MOUD remains underutilized and frequently discontinued.¹

Implications for Pharmacists

Pharmacists play a central, vital role to increasing MOUD use in patients who want to kick addiction, Chang, Peterson, and Erstad said. Their role as community-based healthcare workers means they can work to change minds both among caregivers and in the public at large, especially when it comes to addressing and overcoming the stigma of addiction.

While MOUDs are one part of a person-first treatment plan to address and overcome addiction, they remain underutilized. Yet their potential to help fill the care gap is clear from any cursory look at reputable data. As overdose deaths decline but fentanyl use persists, pharmacists can ensure that this potential does not go unrealized.

REFERENCES

1. Chang, LY, et al. Bridging the gap: Prescribing and optimizing medications for opioid use disorder (MOUD) across the spectrum of care from primary to acute care settings. Presented at: American Society of Health-System Pharmacists 2025 Midyear Clinical Meeting and Exhibition; December 7-10, 2025; Las Vegas, NV.

2. Shahbaz-Arami S, Mocny AC. The evolving role of the pharmacist in Opioid Use Disorder. wwwpharmacytimescom. 2023;17. https://www.pharmacytimes.com/view/the-evolving-role-of-the-pharmacist-in-opioid-use-disorder. Accessed December 15, 2025.

3. Goerig M, Schulte am Esch J. Friedrich Wilhelm Adam Sertürner−the discoverer of morphine. Anasthesiologie, Intensivmedizin, Notfallmedizin, Schmerztherapie: AINS. 1991;26(8):492-498. doi:https://doi.org/10.1055/s-2007-1000624. Accessed December 15, 2025.

4. UChicago Medicine. As morphine turns 200 drug that blocks its side effects reveals new secrets. www.uchicagomedicine.org. Published May 18, 2005. https://www.uchicagomedicine.org/forefront/news/as-morphine-turns-200-drug-that-blocks-its-side-effects-reveals-new-secrets. Accessed December 15, 2025.

5. Wilson W, Marshall T, Clarke J. Harrison Narcotics Tax Act, 1914.; 1914. https://www.naabt.org/documents/Harrison_Narcotics_Tax_Act_1914.pdf

6. Kolodny A, et al. The Prescription Opioid and Heroin Crisis: A Public Health Approach to an Epidemic of Addiction. Annual Review of Public Health. 2015;36(1):559-574. doi:https://doi.org/10.1146/annurev-publhealth-031914-122957