Long-Acting Injectable Formulations of New-Generation Antipsychotics: A Review from a Clinical Perspective

Antipsychotics are the mainstay of the long-term treatment of patients with schizophrenia. In this context, the evidence also supports the effectiveness of long-acting injections (LAIs) or depots of antipsychotics regarding their relapse-preventing properties. When a LAI formulation of risperidone was launched as the first second-generation depot, there was a renaissance of interest in these formulations. In the meantime, olanzapine, paliperidone, and aripiprazole have been approved by regulatory authorities as LAIs in various countries. All studies using the new-generation depots have shown a clear advantage over placebo regarding relapse prevention and symptom reduction. Safety profiles of the long-acting compounds are comparable to their oral formulations with the exception of olanzapine pamoate injections, which can sometimes lead to a post-injection delirium. Despite the fact that many treatment guidelines recommend LAI antipsychotics as an important treatment option for the long-term management of schizophrenia, they are still most frequently used in chronically ill patients with considerable compliance problems. It is imperative to overcome this indication bias in order to be able to utilize all available treatment options in the long-term management of schizophrenia. There is little evidence on comparisons between LAIs and their oral mother compounds, and even less concerning effectiveness comparisons between different depots. The purpose of this manuscript is to review the recent clinical evidence on new-generation depot antipsychotics.