Une étude pharmacoépidémiologique observationnelle de type transversal des pratiques de prescription de la rispéridone injectable à libération prolongée, premier antipsychotique atypique présenté sous cette forme, a été réalisée entre 2005 et 2006 dans neuf établissements du réseau PIC. L’étude a porté sur le suivi pendant un an de tous les patients mis sous ce traitement. L’objectif de ce travail était de faire une analyse des pratiques de prescription en situation réelle de ce nouveau médicament pour apprécier leur adéquation avec l’AMM et les recommandations de l’Afssaps figurant dans le résumé des caractéristiques du produit (RCP) mais aussi d’évaluer l’efficience du médicament en termes de nombre et de délai d’arrêts de traitement. Les résultats de l’étude montrent ainsi une utilisation hors AMM du médicament dans 15 % des cas, un état clinique probablement insuffisamment stabilisé avant la première injection et concomitamment un nombre d’arrêts de traitement sur un an voisin des 54 %.

Atypical antipsychotics or antipsychotics of second generation are still recommended by guidelines for primary use in the treatment of psychotic disorders because of their better neurologic safety and efficacy. However, they require daily dosing, thus compromising their overall efficacy whereas conventional depot neuroleptics provide constant pharmacologic treatment but induce extrapyramidal adverse effects and poor efficacy on negative symptoms. Long acting injectable risperidone (LAIR) is the first long-acting second-generation antipsychotic. Registered in October 2003 and launched in March 2005 in France thanks to Kane et al.’s and Fleischhacker et al.’s reference studies, it was supposed to provide the advantages of conventional long acting formulations of antipsychotics over those of an atypical agent.

The aims of this study, with the description of the prescription practices of LAIR in naturalistic conditions, were to assess the place of this new drug in psychotic medication, with the efficiency value measured by treatment discontinuation rate and analysis of the reasons for discontinuation, and to assess whether the prescriptions practices are or not in adequacy with guidelines and reglementation. In June 2005, we conducted a one-year naturalistic non-randomised open-label study in nine French psychiatric hospitals, members of the PIC network: were included all the patients who received LAIR every 2 weeks, between July 1st 2005 and November 30th 2005.

Prescriptions of 216 patients were examined for 1 year. LAIR was used off label for 15% of the patients. Ninety-two percent of patients were hospitalized at the beginning of the treatment while 72% of the treated patients had dropped out one year after the first injection. Regarding the nature of previous antipsychotic treatments prescribed in the last three months before the first injection of LAIR: 31% patients had received a first generation antipsychotic, half of which had received a depot antipsychotic of first generation and 69% had received a second-generation antipsychotic, among which half had received oral risperidone. The principal reason noted by the clinicians for starting the new formulation was non-observance with anterior treatments. However, oral antipsychotic treatment preceding the first injection was used less than 4 weeks for one third of the patients. When this treatment was oral risperidone, average posology at the first injection was 6.7±2.4mg per day; it was 7.4±2.1mg per day for the patients who received the higher dose of LAIR (50mg/2 weeks). So, it seems that some patients were not sufficiently stabilized by their antipsychotic before the beginning of the long acting treatment. The result was a significant rate of treatment discontinuations (53%) in the following year, principally caused by the withdrawal of the patient’s consent and an insufficient response to treatment.

This investigation provided the opportunity to analyze the prescriptions of a new formulation drug in routine clinical practice. It confirms the need for respecting the authorized indications and the recommendations of good use of a drug to avoid the failures of treatment and also the importance of the role of the pharmacist in recalling it to the physicians.