Withdrawal from risperidone

Risperidone and olanzapine have been widely used in patients with dementia exhibiting behavioural problems. Following the withdrawal of thioridazine from the market, old age psychiatrists and GPs were increasingly atypical antipsychotics, in particular risperidone as it was the only atypical which had been examined in randomised clinical trials (RCTs) with the elderly. In 2004, the advised that both risperidone... 

The U.S. sample was followed openly on risperidone (0.02-0.06 mg/kg/day) for an additional 48 weeks (Findling et ah, 2001). Some 50 children continued to end point, whereas 57 eventually withdrew from the trial for a variety of reasons (11, adverse events 11, insufficient response 35 other [loss to follow-up, withdrawal of consent, etc]). Subjects who received placebo in the acute trial had significant improvements as rated by parents on the Conduct Problem subscale of the NCBRF as they went on to active medication. Subjects already receiving risperidone in the acute trial continued to show improvement on the Conduct Problem subscale in the open-label continuation. Clinician CGI ratings also indicated improvement for participants who were switched from placebo to risperidone. 

Clozapine withdrawal symptoms occur after stopping therapeutic doses (range 200 to 900 mg/day) administered from 4 months to several years. In a study, one-third of patients who were switched directly from clozapine to risperidone remained stable, one-third had to be switched back to clozapine, and one-third were treated with combined risperidone-clozapine or risperidone-neuroleptic ( 480). 

Stanilla et al. (1997) described three cases of delirium with psychotic symptoms due to clozapine withdrawal (see also Adams et al., 1991, for an early report of clozapine withdrawal psychosis). They believed that clozapine produces more severe withdrawal symptoms than typical antipsychotic agents. In a 3-year open label study of quetiapine, Margolese et al. (2004) switched 23 male patients from classical antipsychotics and risperidone to quetiapine Six of the seven patients who relapsed after being stabilized on quetiapine for at least three months met the criteria for supersensitivity psychosis. This is a very high rate, again raising questions about whether atypicals may be more prone to cause tardive psychosis. 

In the final chapter, an expert pharmacologist. Dr. Terrell Gibbs presents a comprehensive review of pharmacotherapies in autism. He details their results from clinical trials, their effectiveness, and their role in the treatment of autistic behaviors. Special emphasis is given to the atypical antipsychotic drug risperidone that is frequently effective for ameliorating symptoms of irritability, hyperactivity, social withdrawal, and stereotypic, repetitive behavior in autism. 

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