Several long-acting injectable (LAI) antipsychotic medications were associated with a reduced hazard of treatment discontinuation compared with oral olanzapine in US veterans with schizophrenia, according to a study results published in The American Journal of Psychiatry.

Researchers conducted the study to examine the real-world comparative effectiveness of antipsychotics used for schizophrenia treatment in the US Department of Veterans Affairs (VA) health care system.

“Effectiveness of antipsychotic drugs is inferred from relatively small randomized clinical trials conducted with carefully selected and monitored participants,” they explained. “This evidence is not necessarily generalizable to individuals treated in daily clinical practice.”

The observational study was based on VA pharmacy data for 37,368 outpatient veterans with schizophrenia. Oral olanzapine was used as a reference for comparisons.

The Pharmacologic Properties of LAIs and Patient Preferences

The study found reduced hazards of discontinuation, compared with oral olanzapine, for clozapine (0.43 hazard ratio), aripiprazole LAI (0.71 hazard ratio), paliperidone LAI (0.76 hazard ratio), antipsychotic polypharmacy (0.77 hazard ratio), and risperidone LAI (0.91 hazard ratio). On the other end of the spectrum, hazards of discontinuation compared with oral olanzapine were increased for oral first-generation antipsychotics (1.16 hazard ratio), oral risperidone (1.15 hazard ratio), oral aripiprazole (1.14 hazard ratio), oral ziprasidone (1.13 hazard ratio), and oral quetiapine (1.11 hazard ratio).

When researchers looked at psychiatric hospitalizations associated with the various antipsychotics, none showed a reduced hospitalization risk compared with oral olanzapine. Quetiapine, however, was linked with a 36% worse hospitalization outcome compared with the reference antipsychotic.

“In a national sample of veterans with schizophrenia, those treated with clozapine, two of the LAI second-generation antipsychotics, and antipsychotic polypharmacy continued the same antipsychotic therapy for a longer period of time compared with the reference drug,” researchers wrote. “This may reflect greater overall acceptability of these medications in clinical practice.”

Reference

Weiser M, Davis JM, Brown CH, et al. Differences in antipsychotic treatment discontinuation among veterans with schizophrenia in the U.S. Department of Veterans Affairs. Am J Psychiatry. Published online July 14, 2021. doi: 10.1176/appi.ajp.2020.20111657