The Role of the Pharmacist in Long-Acting Injectable Therapies for Schizophrenia and Bipolar Disorder

Long-acting injectables (LAIs) are an essential component of care for patients with schizophrenia and bipolar disorder, explained Megan J Ehret, PharmD, MS, BCPP, professor and co-director, Mental Health Program, University of Maryland School of Pharmacy, during a presentation at the American Pharmacists Association (APhA) 2024 Annual Meeting & Exposition in Orlando, Florida. For both conditions, LAIs can help to improve treatment adherence, especially for those with a history of poor or uncertain adherence.

However, Ehret noted the LAI form of treatment is stated in the guidelines as being an available option for any patient who wants that dosage form.

“If someone thinks that they will do better on a long acting, or they just want a long acting, it's fine to use it first-line,” Ehret said during the APhA session. “At our academic medical center, we try to get everyone on LAIs because the adherence is better. The long-term prognosis outcomes for patients are just much better if they're on a stable medication.”

Ehret noted that to help support interest in the LAI option, she will not immediately mention that the LAI treatment would be an injection, as some patients will become disinterested if they know this immediately. Instead, the injection aspect of the treatment is something she mentions after first discussing the benefits of LAIs.

Instead, the injection aspect of the treatment is something she mentions after first discussing the benefits of LAIs. Image Credit: © kazakova0684 - stock.adobe.com

“We say, ‘Hey, if you could have a medication that you only had to take once a month, once every 3 months, once every 6 months, and that you didn't have to remember to take a pill every day—would that be something you're interested in,” Ehret said during the session. “We usually try not to present it as an injection, but to present it as an option, and then get through the injection [part of the conversation].”

The first generation antipsychotic LAIs currently available include haloperidol (Prolixin; Bristol-Myers Squibb) and fluphenazine (Haldol; Janssen Pharmaceuticals), Ehret explained. These LAIs decrease central dopaminergic transmission related to blockade of D2 receptors in the mesolimbic area, and possibly the mesocortical area of the brain. These first generation LAIs antagonize other receptors as well, such as alpha-adrenergic, serotonergic, histaminergic, and muscarinic.

“For anti-psychotic medication, we have our first generations and our second generations. Our first generations are the older ones—haloperidol and fluphenazine—and these really are dopamine blockers,” Ehret said during the session. “With very tight dopamine blockade, we see a lot of adverse effects [AEs] like movement disorders and increased prolactin from those medications, but those were our first LAIs.”

Second generation antipsychotic LAIs currently available include aripiprazole monohydrate (Abilify Maintena; Otsuka Pharmaceutical), aripiprazole (Abilify Asimtufii; Otsuka America Pharmaceutical), aripiprazole lauroxil (Aristada, Aristada Initio; Alkermes), lanzapine pamoate (Zyprexa Relprevv; Eli Lilly and Company), paliperidone palmitate (Invega Sustenna, Invega Trinza, Invega Hafyera; Janssen Pharmaceuticals), risperidone microspheres (Risperdal Consta; Janssen Pharmaceuticals), risperidone microspheres (Rykindo; Luye Pharma), risperidone (Perseris; Indivior), and risperidone (Uzedy; Teva Pharmaceutical). The most common feature of these second generation LAIs is they antagonize the 5-HT2 and DA receptors. For aripiprazole, it partially antagonizes the D2 receptor, Ehret explained.

“Our second generations do not only have some of the dopamine blockade, but also some serotonin blockade as well, which helps offset some of those [AEs] and movement disorders [seen in the first-generation LAIs],” Ehret said during the session. “Once you reach enough dopamine saturation, you're still going to see those, so it's still a risk with all of them.”

Additionally, Ehret noted that the FDA may be approving some new antipsychotic LAIs that may bring a new generation to available treatments for this patient population.

“We are moving into a whole next generation, so we might see some new things from the FDA this summer that has muscarinic effects,” Ehret said during the session. “We're kind of moving outside of dopamine altogether in schizophrenia, which is going to be a really unique area.”

According to Ehret, pharmacists can benefit from learning more about administering LAIs to patients with mental health conditions.

“We're coming into a great time and era to think about the pharmacist giving these injections. In 48 states [in the United States], pharmacists have some capability of providing these injections,” Ehret said during the session. “Many providers, [such as] psychiatrists and nurse practitioners, are looking for pharmacists to administer these because they are doing telehealth, they don't have the staff, and they don't want to store them.”

Ehret explained further that in the state of Maryland, pharmacists and pharmacy interns can administer LAIs. However, for pharmacy interns, they can only administer LAIs if they’ve been through a board-approved training program, which has been added as a requirement to the pharmacy curriculum in Maryland pharmacy programs.

“The intern can do it if they've been through that part of the curriculum, which we built into our school curriculum, so all of our students are eligible, but only if the pharmacist they're working with is trained,” Ehret said during the session.

However, Ehret noted that every state has different requirements for who can administer LAIs. For example, in Washington state, pharmacists are able to administer LAIs, so they have one pharmacist on staff that handles all LAI administration.

“That pharmacist gives injections all day. They're doing 200 plus of these LAIs a month, so they have someone whose sole job it is to be the injection pharmacist,” Ehret said. “If you're near a behavioral health center, it's great to partner and do some outreach. We've seen a lot of people go to telehealth and so they're looking for someone to do these.”

REFERENCE
Ehret MJ. Psychotropic Long-Acting Injectables: An Overview for Pharmacists. American Pharmacists Association 2024 Annual Meeting & Exposition; March 22-25, 2024; Orlando, Florida.