P. Pancheri, R. Delle Chiaie - Vol. 6, Giugno 2000, num.2
Testo Immagini Bibliografia Summary Riassunto Indice
La posizione di amisulpride nella
terapia della schizofrenia
The place of amisulpride in the treatment
of schizophrenia
P. Pancheri,R. Delle Chiaie
III Clinica Psichiatrica, Università di Roma "La
Sapienza"
Fondazione Italiana per lo Studio della Schizofrenia
Amisulpride, a substituted benzamide, is characterised by high selectivity for dopaminergic D2 and D3 receptors, with a slight preference for the latter. These receptors are mainly localised in the limbic system. The drug acts biphasically on dopaminergic neurotransmission, according to dose range. In fact, at low doses (50-200 mg/day) this drug mainly blocks presynaptic autoreceptors, with a resulting potentiation of dopaminergic transmission. On the other hand, the administration of higher doses (400-1000 mg/day) determines the blockade of postsynaptic receptors, with a corresponding decrease in dopaminergic transmission. Such characteristics allow the use of amisulpride to treat both the negative (secondary to a dopaminergic deficit) and the positive syndrome of schizophrenia (due to excess dopaminergic activity).
Method
In this review we analysed the principal controlled clinical trials carried-out to date on the efficacy of amisulpride in the treatment of both positive and negative schizophrenia. At present, clinical data are available on 2000 patients enrolled in various clinical trials. The drug has been tested for efficacy vs haloperidolo, vs. flupenthixol and vs risperidone in the treatment of positive symptoms and vs. placebo or vs. haloperidol in the treatment of negative symptoms.
Results
In the treatment of patients with positive symptoms of schi-
zophrenia, amisulpride showed comparable efficacy with control drugs, but induced less extrapyramidal side effects. In the treatment of schizophrenic patients with negative symptoms, the drug proved significantly more effective than placebo and haloperidol on the negative psychopathological dimension. Results were maintained also in long-term follow-up (6-12 months), in which and the drug proved to be well tolerated.
Conclusions
Results of clinical trials showed that the dual action of amisulpride, according to dose range, is able to correct both excess dopaminergic activity occurring in schizophrenic patients with positive symptoms and dopaminergic deficit associated with negative symptoms. Further, the low incidence of extrapyramidal side effects appears to confirm that drug action is mainly limited to the limbic system, with less involvement of niro-striatal dopaminergic receptors. According to these data, the use of amisulpride in the "dimensional" treatment of schizophrenia appears to be promising.