Sustained improvement of clinical outcome with risperidone long-acting injectable in psychotic patients previously treated with olanzapine

The efficacy and tolerability of risperidone long-acting injectable were investigated in patients with schizophrenia or other psychotic disorders who had previously been symptomatically stable on olanzapine treatment. Patients received risperidone long-acting injectable, 25mg, by intramuscular injection every 2 weeks; the dose could be increased to 37.5 or 50 mg if necessary. Patients were transferred directly from their previous medication to risperidone long-acting injectable without a runin period of oral risperidone treatment.

Of 192 patients recruited, 134 patients (70%) completed the study. The principal reasons for discontinuation were withdrawal of consent (8%), adverse events (6%), insufficient response (5%) and non-compliance (4%). Risperidone long-acting injectable produced a significant improvement (p = 0.0001) in Positive and Negative Syndrome Scale (PANSS) total scores, from 74.2±21.3 at baseline to 65.8±21.4 at endpoint. There were also significant reductions in PANSS subscales (positive symptoms, negative symptoms, general psycho-pharmacology) and Marder factor scores. The Clinical Global Impression increased significantly from baseline to endpoint (p = 0.0001), as reflected by the increase in the proportion of patients rated as ‘not ill’ or ‘borderline ill’ from 10% at baseline to 21% at endpoint. Risperidone long-acting injectable was also associated with significant improvements in Global Assessment of Function, patient satisfaction with treatment, and quality of life, measured on the SF-36 scale. Movement disorders, measured on the Extrapyramidal Symptom Rating Scale, were significantly reduced following the change to risperidone long-acting injectable. Treatment with risperidone long-acting injectable was well tolerated, and no significant weight gain occurred during the study.

This open study suggests that risperidone long-acting injectable produces symptomatic improvement in schizophrenia patients previously considered symptomatically stable with olanzapine, along with improvement in movement disorders. The combination of improved efficacy and good tolerability may have important implications for patient adherence to therapy and subsequent long-term outcomes.