Clozapine therapy in patients with neurologic illness

Clozapine for psychotic disorders in adults with intellectual disabilities

BACKGROUND

Psychosis is three times more common in people with an intellectual disability than in those without an intellectual disability. A low intelligence quotient (IQ) is a defining characteristic for intellectual disability and a risk factor for poor outcome in psychosis. Clozapine is recommended for treatment-resistant psychosis. The effect of psychotropic medication can be different in people with intellectual disability; for example, they may be more prone to side effects. People with an intellectual disability and psychosis form a special subgroup and we wanted to examine if there is randomised controlled trial (RCT) data in this population to support the use of clozapine.

OBJECTIVES

To determine the effects of clozapine for treating adults with a dual diagnosis of intellectual disability and psychosis.

SEARCH METHODS

We searched CENTRAL, Ovid MEDLINE, Embase and eight other databases up to December 2014. We also searched two trials registers, the Cochrane Schizophrenia Group's Register of Trials, and contacted the manufacturers of clozapine.

SELECTION CRITERIA

RCTs that assessed the effects of clozapine, at any dose, for treating adults (aged 18 years and over) with a dual diagnosis of intellectual disability and psychotic disorder, compared with placebo or another antipsychotic medication.

DATA COLLECTION AND ANALYSIS

Three review authors independently screened all titles, abstracts and any relevant full-text reports against the inclusion criteria.

MAIN RESULTS

Of the 1224 titles and abstracts screened, we shortlisted 38 full-text articles, which we subsequently excluded as they did not meet the inclusion criteria. These studies were not RCTs. Consequently, no studies are included in this Cochrane review.

AUTHORS' CONCLUSIONS

There are currently no RCTs that assess the efficacy and side effects of clozapine in people with intellectual disabilities and psychoses. Given the use of clozapine in this vulnerable population, there is an urgent need for a RCT of clozapine in people with a dual diagnosis of intellectual disability and psychosis to fill the evidence gap.

The geriatric population and psychiatric medication

With improvement in medical services in the last few years, there has been a constant rise in the geriatric population throughout the world, more so in the developing countries. The elderly are highly prone to develop psychiatric disorders, probably because of age related changes in the brain, concomitant physical disorders, as well as increased stress in later life. Psychiatric disorders in this population may have a different presentation than in other groups and some of psychopathologies might be mistaken for normal age related changes by an unwary clinician. Therefore the need of the day is to train psychiatrists and physicians to better recognize and manage mental disorders in this age group.

Seizure incidence in psychopharmacological clinical trials: an analysis of Food and Drug Administration (FDA) summary basis of approval reports

BACKGROUND

Clinical trial data provide an approach to the investigation of the effects of psychopharmacological agents, and psychiatric disorders themselves, on seizure threshold.

METHODS

We accessed public domain data from Food and Drug Administration (FDA) Phase II and III clinical trials as Summary Basis of Approval (SBA) reports that noted seizure incidence in trials of psychotropic drugs approved in the United States between 1985 and 2004, involving a total of 75,873 patients. We compared seizure incidence among active drug and placebo groups in psychopharmacological clinical trials and the published rates of unprovoked seizures in the general population.

RESULTS

Increased seizure incidence was observed with antipsychotics that was accounted for by clozapine and olanzapine, and with drugs indicated for the treatment of OCD that was accounted for by clomipramine. Alprazolam, bupropion immediate release (IR) form, and quetiapine were also associated with higher seizure incidence. The incidence of seizures was significantly lower among patients assigned to antidepressants compared to placebo (standardized incidence ratio = .48; 95% CI, .36- .61). In patients assigned to placebo, seizure incidence was greater than the published incidence of unprovoked seizures in community nonpatient samples.

CONCLUSIONS

Proconvulsant effects are associated with a subgroup of psychotropic drugs. Second-generation antidepressants other than bupropion have an apparent anticonvulsant effect. Depression, psychotic disorders, and OCD are associated with reduced seizure threshold.

Brief report: effects of clozapine on self-injurious behavior of two risperidone nonresponders with mental retardation

Atypical antipsychotic medications for self-injurious behavior (SIB), aggression, and destruction among people with mental retardation and development disabilities are becoming increasingly accepted. Most studies are on risperidone and fewer have been conducted on clozapine. The present single-blind study reports marked reductions in SIB and aggression of two persons with profound mental retardation who were nonresponsive to all other behavioral and psychopharmacological interventions, including risperidone. The most effective dose was 200 mg/day. Side effects were mild and the drug was tolerated well.

Mechanism of clozapine-induced agranulocytosis : current status of research and implications for drug development

Clozapine is an atypical antipsychotic agent that has several advantages over conventional antipsychotics, not least of which is its superior efficacy. However, the high risk of agranulocytosis (0.8% of patients) associated with clozapine therapy has resulted in restricted indications for its use.The mechanism of clozapine-induced agranulocytosis is not clear. The target cells affected are the myeloid precursors, although the mature neutrophil may also be targeted simultaneously. There is no convincing evidence of direct toxicity of the parent compound or its stable metabolites (demethyl-clozapine and clozapine N-oxide). Clozapine is also metabolised by liver microsomes, peripheral blood neutrophils and their bone marrow precursors to a chemically reactive intermediate that has been postulated to be a nitrenium ion. This toxic metabolite has been shown to covalently bind to neutrophil proteins, suggesting that it may be involved in the pathogenesis of the toxicity. However, it is not clear how toxicity is mediated. The nitrenium ion may bind to essential cellular proteins and disrupt neutrophil function or, alternatively, it may act as a hapten and initiate an immune reaction resulting in immune-mediated destruction of the neutrophil. Indirect evidence exists to support both mechanisms, although clear direct evidence is still lacking. The role of cytokines and apoptosis in the pathogenesis of the agranulocytosis is unclear.The reason why only approximately 1% of individuals who are treated with clozapine are affected by agranulocytosis has not been elucidated. Evidence exists to implicate both the major histocompatibility complex antigens and heat shock protein variants in determining individual susceptibility, although more patients of different ethnic backgrounds need to be studied.The ultimate aim of research into clozapine-induced agranulocytosis should be to either prospectively predict which individuals are going to develop agranulocytosis and/or to develop analogues that retain efficacy but are not toxic. The former is complicated by the fact that predisposition may be multifactorial, and thus prediction may require multiple tests that may be of statistical but not absolute validity. The latter depends on identifying the mechanism of toxicity and the chemical characteristics of clozapine that are responsible for the toxicity. This knowledge may allow rational design of new analogues that do not cause agranulocytosis.