Injectable vs Oral Antipsychotics: Which Best Prevents Schizophrenia Relapse?

Long-acting injectable antipsychotic medications and clozapine were associated with lowest risks for treatment failure and rehospitalization in patients with schizophrenia, according to a recent prospective study.

In the study, the researchers collected data on all patients in Sweden with a schizophrenia diagnosis who were 16 to 64 years of age in 2006 using nationwide databases from July 1, 2006 to December 31, 2013. Of the 29,823 patients included in the study, 12,822 were women, 17,001 were men, and the mean age was 44.9 years. Within-individual analyses were used for the primary analysis in order to eliminate selection bias, and hazard ratios (HR) were calculated in secondary analyses.
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The risk of rehospitalization and treatment failure, which was defined as psychiatric rehospitalization, suicide attempt, discontinuation or switch to another medication, or death, were assessed as the main outcomes.

A total of 13,042 patients (43.7%) were rehospitalized and 20,225 patients (71.7%) experienced treatment failure during follow-up.

Compared with no antipsychotic medication use, the lowest risk for psychiatric rehospitalization was associated with monotherapy of once-monthly long-acting injectable paliperidone (HR 0.51), long-acting injectable zuclopenthixol (HR 0.53), clozapine (HR 0.53), long-acting injectable perphenazine (HR 0.58), and long-acting injectable olanzapine (HR 0.58). Additionally, long-acting injectable antipsychotic medications were associated with a substantially lower risk of rehospitalization compared with their equivalent oral formulations.

The highest risk for rehospitalization was associated with oral flupentixol (HR 0.92) and oral perphenazine (HR 0.86).

Clozapine and long-acting injectable antipsychotic medications were also associated with lower rates of treatment failure compared with oral olanzapine, the most widely used medication.

“Clozapine and long-acting injectable antipsychotic medications were the pharmacologic treatments with the highest rates of prevention of relapse in schizophrenia,” the researchers concluded. “The risk of rehospitalization is about 20% to 30% lower during long-acting injectable treatments compared with equivalent oral formulations.”

—Melissa Weiss

Reference:

Tiihonen J, Mittendorfer-Rutz E, Majak M, et al. Real-world effectiveness of antipsychotic treatments in a nationwide cohort of 29 823 patients with schizophrenia [published online June 7, 2017]. JAMA Psychiatry. doi:10.1001/jamapsychiatry.2017.1322.