Research and Clinical Trials on Risperidone (Risperdal)

By Dr Greg Mulhauser
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This list of current clinical research trials on Risperidone (Risperdal) is followed by a short set of abstracts from the most recent research articles published on the drug.

Article Contents

Risperidone (Risperdal) Clinical Research Trials

From our searchable database at ClinicalTrialsFeeds.org, this list includes all the latest information about clinical trials involving Risperidone (Risperdal).

 

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Current Research Literature on Risperidone (Risperdal)

Here are abstracts for some of the latest research articles to have appeared on Risperidone (Risperdal):

[Effects of the anticholinesterase drug neuromidin in patients with schizophrenia with marked neurocognitive deficits.]

Zh Nevrol Psikhiatr Im S S Korsakova. 2008; 108(11): 28-35
Morozova MA, Beniashvili AG, Rupchev GE, Lepilkina TA, Starostin DS, Brusov OS
An objective of the study was to investigate the effectiveness of neuromidin in stable schizophrenic patients with predominance of symptoms of pseudoorganic deficits. Fifty-five patients stable after a transition from routine medication to monotherapy with risperidone were randomized into two groups with add-on placebo or neuromidin treatment. Patients were studied during 24 weeks. The PANSS and a battery of neurocognitive tests were used for assessment of treatment. In the end of the trial, positive changes on the following PANSS items - N1, N2, N6, N7, G4, G7 and G13 were observed in the neuromidin group. In the placebo group, the changes were found only on one PANSS item - N2. The decrease of scores on this item (emotional withdrawal) during the study was more significant only in the patients receiving neuromidin (p=0,037). The results of assessment of cognitive functioning showed the positive changes in visual-spatial memory, attention, retention and retrieval of data, planning in the group treated with neuromidin. In the placebo group, the positive changes were observed only in one index - one type of mistakes (omissions) in visual-spatial memory test. In the end of the trial, between-group differences were significant for planning - number of tasks with time-limit violation and rule violations. All differences were beneficial for patients treated with neuromidin. Not all tests were sensitive to changes in cognitive status of patients: indices of working memory, psychomotor speed, flexibility of attention were not changed significantly in both groups, nor they changed between groups. The authors conclude that the problem of rationality of add-on anticholinergic treatment in schizophrenia is not solved yet due to the difficulties in selection of patients and tests for cognitive assessment. The need of further studies is emphasized.

Risperidone-Induced Enuresis in Two Children with Autistic Disorder.

J Child Adolesc Psychopharmacol. 2008 Nov 13;
Hergüner S, Mukaddes NM
ABSTRACT Introduction: Risperidone appears to be effective in treating behavioral problems in children with autistic disorder. Although increased appetite, weight gain, and sedation are among the most common side effects, risperidone-induced enuresis is rarely reported. Method: We will present two cases with risperidone-induced enuresis, and discuss our findings in the context of current literature. Results: Two children aged 11 and 10 years, diagnosed with autism and mental retardation, have developed new-onset diurnal and nocturnal enuresis respectively on their first and second weeks of risperidone monotherapy (1.5 and 1 mg/day). They did not experience sedation, and their medical history and workup were unremarkable. As enuresis did not resolve spontaneously, we decided to substitute risperidone with olanzapine. Enuresis ceased rapidly after discontinuation of risperidone with no emergence when patients were treated with olanzapine 5 mg/day for a period of 6 months and 1 year, respectively. Discussion: Although the pathophysiology of antipsychotic-induced enuresis remains unclear, a number of mechanisms including alpha(1)-adrenergic blockade, dopamine blockade, and antimuscarinic effects has been proposed. Olanzapine has lower alpha(1)-adrenergic and dopaminergic blockade properties, thus changing risperidone to olanzapine may be an alternative modality in risperidone-induced enuresis when antipsychotic treatment is crucial. Clinicians should be more vigilant about screening for this side effect, especially in younger population with developmental disabilities.

Pharmacological analysis of the novel, rapid and potent inactivation of the human 5-HT7 receptor by risperidone, 9-OH-risperidone and other "inactivating antagonists"

Mol Pharmacol. 2008 Nov 10;
Knight JA, Smith C, Toohey N, Klein MT, Teitler M
In a previous publication, using h5-HT7 receptor-expressing HEK293 cells, we reported the rapid, potent inactivation of the h5-HT7 receptor stimulation of cAMP production by three antagonists: risperidone, 9-OH-risperidone, and methiothepin (Smith et al., 2006). In order to better understand the drug-receptor interaction producing the inactivation we a) expanded the list of inactivating drugs; b) determined the inactivating potencies and efficacies by performing concentration-response experiments and c) determined the potencies and efficacies of the inactivators as irreversible binding site inhibitors. Three new drugs were found to fully inactivate the h5-HT7 receptor: lisuride, bromocryptine, and metergoline. As inactivators these drugs diplayed potencies of 1, 80, and 321nM, respectively. Pre-treatment of 5-HT7-expressing HEK cells with increasing concentrations of the inactivating drugs risperidone, 9-OH-risperidone, methiothepin, lisuride, bromocryptine, and metergoline potently inhibited radiolabeling of the h5-HT7 receptor, with IC50 values of 9, 5.5, 152, 3, 73, and 10nM, respectively. Surprisingly, maximal concentrations of risperidone and 9-OH-risperidone inhibited only 50% of the radiolabeling of h5-HT7 receptors. These results indicate that risperidone and 9-OH-risperidone may be producing the inactivating effect through a different mechanism than lisuride, bromocryptine, metergoline, and methiothepin. These results are not interpretable using the conventional model of GPCR function. This complex appears capable of assuming a stable inactive conformation due to the interaction of certain antagonists. The rapid, potent inactivation of the receptor-G-protein complex by antagonists implies a constitutive, pre-existing complex between the h5-HT7 receptor and a G-protein.

Glucose and lipid disturbances after 1 year of antipsychotic treatment in a drug-naïve population.

Schizophr Res. 2008 Nov 5;
Perez-Iglesias R, Mata I, Pelayo-Teran JM, Amado JA, Garcia-Unzueta MT, Berja A, Martinez-Garcia O, Vazquez-Barquero JL, Crespo-Facorro B
OBJECTIVE: This study examined the main metabolic side effects induced by antipsychotic treatment in a cohort of first episode drug-naïve subjects after the first year of treatment. METHODS: A randomized, open-label, prospective clinical trial was conducted. Participants were 164 consecutive subjects included in a first episode program and never treated with antipsychotic medication. Patients were assigned to haloperidol, olanzapine or risperidone. The main outcome measures were changes at 1 year in fasting glucose parameters (glucose, insulin levels and insulin resistance index) and changes in fasting lipid parameters (total cholesterol, triglycerides, LDL cholesterol, HDL cholesterol). RESULTS: 144 of the total sample were evaluated at 1 year. There was a statistically significant increase in the mean values of insulin levels, insulin resistance index, total cholesterol, LDL-cholesterol and triglycerides. No pathological values in fasting glucose plasma levels were found at baseline and there were no changes after 1 year. Weight gain was positively correlated with changes in insulin levels, insulin resistance index and triglyceride levels. We did not detect statistically significant differences between treatments in any of the parameters evaluated. CONCLUSIONS: Fasting glycaemia and insulin concentrations at baseline do not support the hypothesis that schizophrenia is associated with an underlying abnormality in glucose metabolism. The changes in insulin and lipid parameters at 1 year seem to be related to the magnitude of weight gain. There were no significant differences between haloperidol, olanzapine and risperidone concerning metabolic adverse effects after the first year of treatment.

Chronic risperidone treatment preferentially increases rat erythrocyte and prefrontal cortex omega-3 fatty acid composition: Evidence for augmented biosynthesis.

Schizophr Res. 2008 Nov 6;
McNamara RK, Able JA, Jandacek R, Rider T, Tso P
Prior clinical studies suggest that chronic treatment with atypical antipsychotic medications increase erythrocyte and postmortem prefrontal cortex (PFC) omega-3 fatty acid composition in patients with schizophrenia (SZ). However, because human tissue phospholipid omega-3 fatty acid composition is potentially influenced by multiple extraneous variables, definitive evaluation of this putative mechanism of action requires an animal model. In the present study, we determined the effects of chronic treatment with the atypical antipsychotic risperidone (RISP, 3.0 mg/kg/d) on erythrocyte and PFC omega-3 fatty acid composition in rats maintained on a diet with or without the dietary omega-3 fatty acid precursor, alpha-linolenic acid (ALA, 18:3n-3). Chronic RISP treatment resulted in therapeutically-relevant plasma RISP and 9-OH-RISP concentrations (18+/-2.6 ng/ml), and significantly increased erythrocyte docosahexaenoic acid (DHA, 22:6n-3, +22%, p=0.0003) and docosapentaenoic acid (22:5n-3, +18%, p=0.01) composition, and increased PFC DHA composition (+7%, p=0.03) in rats maintained on the ALA+ diet. In contrast, chronic RISP did not alter erythrocyte or PFC omega-3 fatty acid composition in rats maintained on the ALA- diet. Chronic RISP treatment did not alter erythrocyte or PFC arachidonic acid (AA, 20:4n-6) composition. These data suggest that chronic RISP treatment significantly augments ALA-DHA biosynthesis, and preferentially increases peripheral and central membrane omega-3 fatty acid composition. Augmented omega-3 fatty acid biosynthesis and membrane composition represents a novel mechanism of action that may contribute in part to the efficacy of RISP in the treatment of SZ.

 

This page was last reviewed by Dr Greg Mulhauser, Friday, 4 July 2008.

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