Do we need another atypical antipsychotic?

Atypical antipsychotics were a great advance in the treatment of schizophrenia. But, there is still no atypical antipsychotic with an exceptional efficacy and safety profile for all patients. Clinicians are required to draw on their experiential knowledge to examine suitable options for individual patients. Following its suspension in 1998, the safety and efficacy of sertindole have been investigated in several post-marketing studies based in clinical settings. These have provided the safety data to support the reintroduction of sertindole, as well as specific examples demonstrating that certain patients, in particular, may benefit from a switch from other atypical antipsychotics to sertindole. Sertindole's individual and mostly favourable profile of treatment-emergent effects and safety allows for flexibility in treating patients. The propensity of sertindole to cause anticholinergic effects, which can be particularly troublesome, is small and, more recently, there have been suggestions that sertindole may have beneficial effects on cognition.

The atypical antipsychotic sertindole enhances efflux of dopamine and its metabolites in the rat cortex and striatum

Previous studies have shown that sertindole (1-[2-[4-[5-chloro-1-(4-fluorophenyl)-1H-indol-3-yl]-1-piperidinyl]ethyl ]-2 imidazolidinone), an atypical antipsychotic drug that is a potent 5-HT2A and dopamine D2 receptor antagonist, preferentially affects mesocorticolimbic rather than mesostriatal dopamine neurons. Using in vivo microdialysis in conscious rats, we investigated the effects of sertindole on dopamine release and metabolism in the striatum and the medial prefrontal cortex. Systemic administration of sertindole dose dependently enhanced dopamine release in the medial prefrontal cortex and the striatum to the same extent.

EPOS: Increasing our understanding of the treatment of schizophrenia; Start of a prospective referenced cohort study of sertindole in clinical practice

Sertindole is a new limbic-selective antipsychotic agent which has recently received marketing authorization in several countries across Europe for the treatment of schizophrenia. The experience gained in around 2200 patients treated with sertindole in controlled clinical trials has enabled optimal targeting of sertindole to those patient groups who will benefit most and who are least likely to experience adverse effects. Ultimately, it is how a new medicinal product is used in clinical practice, how it performs in everyday life, and how the patient who takes it feels and functions that determine the real benefit/risk ratio of a new medicinal product. The European Post-marketing Observational Serdolect® project (EPOS) is a post-marketing, referenced, observational, cohort, safety study in the treatment of schizophrenic patients initiated earlier this year. It is planned to recruit over 12 000 patients in two cohorts in centres throughout Europe. The aims are to provide a full safety evaluation of sertindole under marketed conditions at the relevant clinical dosage, and further, to provide epidemiological data on schizophrenic patients receiving sertindole or other treatment under the usual clinical conditions in Europe. At the moment, the study is the only one of its kind to be undertaken in schizophrenia and will provide important new data for psychiatrists around the world.

A randomized, controlled, dose-ranging trial of sertindole in patients with schizophrenia

Sertindole is a novel antipsychotic agent with high selectivity for the mesolimbic dopaminergic pathway and nanomolar affinities for dopamine D2, serotonin 5-HT2, and norepinephrine NE alpha 1 receptors. This 40-day randomized, placebo-controlled, dose-ranging multicenter study was designed to assess the effect of sertindole on previously neuroleptic-responsive, hospitalized schizophrenic patients (n = 205). Sertindole doses began at 4 mg/day and were increased to 8, 12, or 20 mg/day, depending on randomization. Efficacy measures included the Positive and Negative Syndrome Scale (PANSS), Brief Psychiatric Rating Scale (BPRS), and Clinical Global Impression (CGI). Extrapyramidal symptoms (EPS) were assessed by movement rating scales, EPS-related adverse events, and use of anti-EPS medications. A dose-related improvement was observed for PANSS, BPRS, and CGI, with statistically significant mean differences (P < 0.05) between placebo and 20-mg/day sertindole (decreases from baseline of -5.8 versus -16.9 for PANSS, -4.8 versus -10.4 for BPRS, respectively). The differences in CGI final improvement score between placebo and 20-mg/day sertindole were 3.8 versus 2.9, respectively. EPS-related events were comparable in the placebo and sertindole groups. In conclusion, sertindole 20 mg/day was effective, well tolerated, and not associated with significant motor system abnormalities.

Mechanisms of action of atypical antipsychotic drugs: a critical analysis

Various criteria used to define atypical antipsychotic drugs include: 1) decrease, or absence, of the capacity to cause acute extrapyramidal motor side effects (acute EPSE) and tardive dyskinesia (TD); 2) increased therapeutic efficacy reflected by improvement in positive, negative, or cognitive symptoms; 3) and a decrease, or absence, of the capacity to increase prolactin levels. The pharmacologic basis of atypical antipsychotic drug activity has been the target of intensive study since the significance of clozapine was first appreciated. Three notions have been utilized conceptually to explain the distinction between atypical versus typical antipsychotic drugs: 1) dose-response separation between particular pharmacologic functions; 2) anatomic specificity of particular pharmacologic activities; 3) neurotransmitter receptor interactions and pharmacodynamics. These conceptual bases are not mutually exclusive, and the demonstration of limbic versus extrapyramidal motor functional selectivity is apparent within each arbitrary theoretical base. This review discusses salient distinctions predominantly between prototypic atypical and typical antipsychotic drugs such as clozapine and haloperidol, respectively. In addition, areas of common function between atypical and typical antipsychotic drug action may also be crucial to our identification of pathophysiological foci of the different dimensions of schizophrenia, including positive symptoms, negative symptoms, and neurocognitive deficits.

Metabolism of sertindole: identification of the metabolites in the rat and dog, and species comparison of liver microsomal metabolism

1. The main exretion pathways of a novel antipsychotic drug, sertindole, in the rat and dog are faecal excretion via intestinal secretion and biliary excretion respectively. 2. Similar liver microsomal metabolic patterns were observed in the rat, monkey, and man, and Lu 30-131 (5-hydroxy-serindole) and Lu 30-148 (4-hydroxy-serindole) were the major metabolites, and Lu 25-073 (nor-sertindole) and Lu 28-092 (dehydro-sertindole) were minor ones. In the dog, however, Lu 31-096 (3'-fluoro-4'-hydroxy-sertindole) and Lu 30-148 (4-hydroxy-sertindole) were the major metabolites, and Lu 25-073 (nor-sertindole), Lu 28-092 (dehydro-sertindole), and Lu 30-131 (5-hydroxy-sertindole) were minor ones. These findings suggest that the metabolism of sertindole in man resembles those in the rat and monkey and is different from that in the dog. 3. Rat in vitro and in vivo liver metabolites, dog liver microsomal metabolites, and dog biliary metabolites were isolated and identified by liquid chromatography/mass spectrometry and/or 1H-nmr. 4. Two metabolites, Lu 31-096 (3'-fluoro-4'-hydroxy-sertindole) and Lu 31-154 (3'-fluoro-4'-hydroxy-dehydro-sertindole), were formed via the 'NIH shift' mechanism. 5. Sertindole is metabolized by hydroxylation at the 4- and 5-positions on the imidazolidinone ring, N-dealkylation, and an NIH shift at the fluorophenyl group. Further metabolism (dehydration, oxidation, hydroxylation, glucuronidation and sulphation) was also observed. 6. In the rat, oxidation at the imidazolidinone ring and N-dealkylation are the main metabolic reactions. On the other hand, in the dog, the NIH shift at the fluorophenyl group, followed by conjugation is the main metabolic pathway.

Differential effects of classical and newer antipsychotics on the hypermotility induced by two dose levels of D-amphetamine

The inhibitory effects of a variety of established and putative antipsychotic compounds on the hypermotility induced by D-amphetamine at two dose levels (0.5 and 2.0 mg/kg) have been studied. Classical antipsychotics (haloperidol, fluphenazine and cis(Z)-flupentixol) and the selective dopamine D2 receptor antagonist remoxipride inhibit hypermotility in the two conditions with similar potencies, whereas sertindole, clozapine, risperidone, ziprasidone and olanzapine preferentially inhibit the effect of the low dose of D-amphetamine (selectivity ratios between 6.5 and 18). Seroquel, amperozide and the selective 5-HT2A receptor antagonist MDL 100.151 ((+/-)-alpha-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenylethyl)]-4-p iperidine - methanol) have no effect on D-amphetamine 2.0 mg/kg, but inhibit the response to D-amphetamine 0.5 mg/kg. The alpha 1-adrenoceptor antagonist prazosin inhibits the motility response to D-amphetamine 0.5 mg/kg with slightly higher potency than that to D-amphetamine 2.0 mg/kg, whereas the 5-HT2A/2C receptor antagonist ritanserin selectively inhibits the effect of D-amphetamine 0.5 mg/kg. The histamine H1 receptor antagonist mepyramine is ineffective in both models. All compounds, except remoxipride, MDL 100.151 and ritanserin (which are ineffective) inhibit spontaneous locomotor activity at dose levels close to those inhibiting the response to D-amphetamine 2.0 mg/kg. Prazosin has partial inhibitory effect. In conclusion, dopamine antagonism has similar inhibitory effect on hyperactivity induced by low and high D-amphetamine dosages, alpha 1-adrenoceptor antagonism also contributes to both effects, whereas 5-HT2 receptor antagonism selectively interacts with the low D-amphetamine dose. This indicates that the responses to D-amphetamine 0.5 and 2.0 mg/kg are differently modulated by these neurotransmitters.(ABSTRACT TRUNCATED AT 250 WORDS)