[Long-acting injectable risperidone: naturalistic study in three hospitals in Aquitaine]

Injectable risperidone is the first long-acting second-generation antipsychotic. A middle-term naturalistic study has been conducted with the first treated patients of three psychiatric hospitals in Aquitaine.

Two evaluations of these patients were performed by psychiatrists: the first before the beginning of treatment and the second after six months. Data on efficacy and tolerance of the drug were obtained from in-patients who were unstable or non-compliant with their previous treatment. Two scales were used to highlight efficacy (positive and negative syndrome scale (PANSS) and clinical global impression (CGI)). All adverse events had to be notified in a general form and AIMS was used for extrapyramidal symptoms. Patient's quality of life was auto-evaluated by TEAQV. The pain on injection was assessed by the patients on a visual analogic scale.

Patients were treated between February 4th and December 4th 2004. Among the 71 treated patients, 27 (38%) discontinued treatment before the six months, due to: lost to follow-up (11.3%), consent withdrawn (9.9%), insufficient response (7%), adverse event (2.8%) or unknown reason (7%). The results of efficacy and tolerance concern 37 patients (52%) with a mean age of 32.8 (+/-7.8) years. Patient's PANSS score was 86.6 (+/-21.4) at the beginning of treatment. Mean decrease of this score was 13.2 after six months. Efficacy of the product is shown by 40.5% of the patients who decreased more than 20% of their initial PANSS score. CGI showed a global improvement "mild" to "great" with 46% of "strongly" to "very strongly" improved patients. Adverse reactions reported are known with risperidone: extrapyramidal symptoms (29.7%), weight gain (13.5%), dry-mouth syndrome (13.5%), hypotension (8.1%), sexual disorders (5.4%) and hyperprolactinemia (2.7%). Extrapyramidal symptoms were still the most common adverse events, as in the initial evaluation. Patients claimed their quality of life was unchanged after six months in comparison with the initial evaluation. They evaluated pain at injection site as moderate (2.6/10).

The results of efficacy have been compared to the results published in the two studies that made it possible to obtain marketing autorisation of the drug in USA. The PANSS results for efficacy were not statically different from the results of the two reference studies (except for negative symptoms: there was no statistical difference observed between initial and final scores in our study, probably due to the small size of the sample). This study highlights several positive aspects for long-acting injectable risperidone (innovating pharmaceutical presentation: aqueous suspension which contains microspheres, moderate pain at injection site, efficacy in 40.5% of initially unstable patients, discharge and no rehospitalisation in most patients, decrease of the use of anticholinergic products) but also shows several negative aspects (frequency of injections--every two weeks--, high percentage of treatment discontinuation, same adverse event profile as oral risperidone, no improvement in quality of life).

Despite the small size of the sample, this study presents a view of the use of the drug in realistic conditions and appears to show that long-acting injectable risperidone is probably the most appropriate treatment for stable, discharged patients.