Three-year clinical experience with the long-acting injectable formulation of the atypical antipsychotic risperidone

Background

Risperidone is the only atypical drug available as a depot or long-acting injectable formulation. Long-acting intramuscular risperidone injection (RLAI) is a formulation that combines the benefits of atypical antipsychotics with improvements in compliance associated with depot formulations.

Materials and methods

We systematically followed-up 33 (24 male and 9 female) -according to DSM-IV- schizophrenic patients (paranoid:20, disorganized:10 and undifferentiated type:3), with average age 39.54 years (26-55) and average duration of illness 14.96 years (5-26), for more than 18 months. Patients demonstrated a variety of reasons for receiving a long-acting injectable antipsychotic drug, including a history of non-compliance (57%), insufficient control of symptoms with previous atypical antipsychotics (28%), and adverse events with other treatments (15%). 21 (64%) patients were hospitalized when RLAI was initiated. The average dose of RLAI was 50.75mg every two weeks. Antipsychotic, anticholinergic or benzodiazepines coprescription was infrequent.

Results

After more than 18 months of treatment (average duration of follow-up: 25.125 months) many patients (73%) show significant and sustained clinical improvement in their symptoms over their original condition (CGI and BPRS score) and had no relapse or admission during this period despite their history of frequent exacerbations of symptoms and many hospitalizations. Treatment was well tolerated as demonstrated through the adverse event profile.

Conclusions

Long-acting risperidone injection seems to be an important advance in the management of patients requiring continuous antipsychotic therapy for long-term maintenance treatment. It seems to have the potential to extend benefits of assured medication delivery and improved long-term outcomes. Initiating it during inpatient treatment may be an important strategy in improving long-term outcomes among patients with schizophrenia.