Dosing issues and depot medication in the maintenance treatment of schizophrenia

Antipsychotic medication has proved to be of enormous value in the long-term treatment of schizophrenia. Maintenance medication has been shown to reduce rates of relapse and rehospitalization substantially and to enable patients to benefit from psychosocial treatments and vocational rehabilitation. At the same time, improving compliance while optimizing the benefits and minimizing the risks associated with long-term drug treatment has been a major challenge. Depot medications are a valuable part of a maintenance strategy for many patients. Considerable data are now available on dose-response relationships with depot drugs, improving our ability to use them judiciously.

Plasma clozapine levels and clinical response for treatment-refractory schizophrenic patients

OBJECTIVE

The purpose of this study was to determine if plasma clozapine levels were associated with treatment response.

METHOD

To examine this question, neuroleptic nonresponsive patients with schizophrenia or schizoaffective disorder were given clozapine, which was titrated to 500 mg/day by day 14 of treatment, and the dose was held fixed at least through day 21. Subsequently, clozapine doses were adjusted as clinically indicated, up to a maximum of 900 mg/day. Plasma clozapine levels were obtained at weeks 3 and 6, and standard clinical ratings (Brief Psychiatric Rating Scale [BPRS] and Clinical Global Impression) were done at baseline and at weeks 3 and 6.

RESULTS

Data from 45 subjects were analyzed. There were no correlations between plasma clozapine levels and change in BPRS scores at treatment weeks 3 and 6. However, when the subjects were classified as responders or nonresponders, therapeutic response was associated with clozapine blood levels above 350 ng/ml.

CONCLUSIONS

This study suggest that clozapine blood levels are correlated with clinical response.

Risperidone: efficacy and safety

This article reviews the evidence for the efficacy and effectiveness of risperidone in persons with schizophrenia. Nine published double-blind studies compare risperidone with another antipsychotic medication and/or placebo. All were conducted in the acute phase of illness. Risperidone's antipsychotic efficacy is shown to be consistently superior to that of placebo and at least comparable to that of haloperidol and perphenazine for patients in the acute phase of schizophrenia. Further research is necessary to determine the effectiveness of risperidone and its efficacy both as a maintenance treatment and in treatment-refractory and deficit-state patients.

Clinical effects of clozapine in chronic schizophrenia: response to treatment and predictors of outcome

OBJECTIVE

This study addressed the unique clinical properties attributed to the atypical antipsychotic clozapine, including its efficacy in patients with treatment-refractory psychosis and against negative symptoms, its lack of acute extrapyramidal side effects, and the longer time course of its therapeutic effects.

METHOD

The clinical responses of 84 schizophrenic inpatients (66 with treatment-refractory illness and 18 who were intolerant of antipsychotic treatment) were examined. After all previous antipsychotic medications had been withdrawn, the patients were treated with clozapine according to a standardized titration and dosage schedule. Patients who tolerated and responded to treatment were discharged and maintained on a regimen of clozapine for up to 52 weeks. Patients were evaluated for behavioral response and side effects after weeks 3, 6, 12, 26, 39, and 52 of treatment.

RESULTS

Fifty percent of the patients with treatment-refractory illness and 76% of the treatment-intolerant patients responded to clozapine in up to 52 weeks. The optimal period for a trial of clozapine appeared to be 12-24 weeks. Clozapine exhibited therapeutic effects on negative symptoms, but these were not clearly independent of its effects on positive symptoms and extrapyramidal side effects. Several variables, including early age at onset of illness and female gender, were found to be predictors of poor response to treatment. Predictors of good response included the presence of extrapyramidal side effects during previous treatment with classic neuroleptics and a diagnosis of paranoid schizophrenia.

CONCLUSIONS

These findings have important implications for the use of clozapine and our understanding of the pathophysiology of treatment-resistant schizophrenia.

Towards more effective antipsychotic treatment

The development of antipsychotic drugs has followed two complementary approaches, either towards highly specific actions (e.g. on the dopamine receptor) or targeting a broad range of receptors. The properties of 'atypical' agents challenge the original dopamine hypothesis and suggest roles for a variety of dopamine receptors and for other pathways, such as serotonin. Older drugs, despite their proven efficacy in relieving many schizophrenic symptoms, have several drawbacks, being ineffective in some patients, relatively ineffective against negative symptoms, and causing adverse neurological effects which may, in turn, be associated with poor compliance. Among newer agents, currently available ones, such as clozapine and risperidone, offer the possibility of more effective control of negative symptoms and an improved side-effect profile, while others are in earlier stages of development. However, much still remains to be understood about their mechanisms of action.

Methylphenidate response, psychopathology and tardive dyskinesia as predictors of relapse in schizophrenia

Despite the proven efficacy of acute and maintenance pharmacotherapy in schizophrenia, practical methods for identifying patients who require continuous treatment to prevent relapse have not been established. We hypothesized that a pathologic overactivity of mesolimbic and mesocortical dopamine neural systems, that mediates positive psychotic symptoms in the acute phase of the illness, persists in some outpatients who are vulnerable to relapse despite appearing clinically stable. To test and determine if putative measures of central nervous system dopamine activity predict outcome, 41 stable outpatients receiving neuroleptic maintenance treatment underwent provocative tests with methylphenidate in a randomized double-blind placebo controlled design in which behavioral, neuromotor, biochemical, and cardiovascular responses were measured. Patients were then withdrawn from medication and monitored for 52 weeks, or until relapse. The results indicate that psychotic symptoms and their activation by methylphenidate, and the presence of tardive dyskinesia are associated with each other and with a higher risk of relapse. These findings partially support our hypothesis and offer potentially useful measures for the identification of candidates for reduced dose neuroleptic maintenance treatment strategies in schizophrenia.

Cerebral morphometry and clozapine treatment in schizophrenia

Studies of brain morphology in schizophrenia may be informative about basic pathophysiologic processes, provide clinically useful indicators of treatment response, and lead to the identification of markers for selective treatment effects. This paper reviews findings from magnetic resonance imaging studies of patients with schizophrenia conducted at Hillside Hospital, with special attention to (1) findings that have helped distinguish patients who respond well to typical neuroleptics from those who have gone on to trials of clozapine, (2) the capacity of morphological measures to predict clozapine treatment response, and (3) the possibility that selective hypertrophy of striatal structure may be caused by chronic treatment with typical neuroleptics, but not by clozapine.

Clozapine, negative symptoms, and extrapyramidal side effects

The importance of persistent negative symptoms in schizophrenia as a limiting factor in psychosocial and vocational rehabilitation has been increasingly emphasized. As a result, treatment trials and new drug development programs are focusing more attention on negative symptoms. Unfortunately, there is enormous phenomenological overlap between negative symptoms and neuroleptic-induced parkinsonism. We report data from a cohort of 56 clozapine-treated patients demonstrating significant correlations between measures of akinesia and anergia. Despite an average drug washout of over 2 weeks, the persistence of drug-induced parkinsonism can confound the assessment of therapeutic drug effects on negative symptoms.

The use of clozapine in neurologic disorders

The advent of clozapine has marked a major advance in the treatment of schizophrenia because of its low incidence of extrapyramidal side effects and superior efficacy. Because of a relatively high incidence of agranulocytosis, approved indications for use are limited to treatment-refractory or neuroleptic-intolerant patients with schizophrenia. However, an emerging body of literature suggests that clozapine may be preferable to typical neuroleptics for treating psychosis in certain neurologic disorders. In addition, clozapine may have a place in the treatment of movement disorders that are caused by or are a result of the pharmacologic treatment of some neurologic illnesses. In general, clozapine doses used in these settings are lower than that for treating psychosis in schizophrenia. This article reviews the experience with clozapine in selected neurologic disorders.

Clozapine dose in the United States and Europe: implications for therapeutic and adverse effects

The report (1) provides an overview of clozapine doses used in trials conducted in Europe and the United States, (2) compares data on efficacy, and (3) compares side effects of clozapine from recent European and U.S. investigations. The reviewed European trials used a mean dose of 283.7 mg/day, while the mean dose in the U.S. studies was 444 mg/day. Even though the mean doses used in the United States are considerably higher than those used in Europe, the response rates for the two continents are strikingly similar. The main differences in a comparison of two samples evaluated in New York and Innsbruck were found in the prevalence of seizures (Innsbruck, 0%; United States, 7.1%) and confusion (Innsbruck, 0%; United States, 14%). Excitement was less prevalent in the U.S. study. The data presented appear to suggest that a lower dose of clozapine may be as effective as a higher dose in the management of treatment-resistant schizophrenic patients and may cause fewer side effects.

Clozapine and weight gain

BACKGROUND

To investigate the association of clozapine treatment and weight gain, we studied short- and long-term weight gain, correlation of weight gain with treatment response, and risk factors for weight gain in 82 patients with chronic schizophrenia who received clozapine treatment for up to 90 months.

METHOD

Weight values were obtained through retrospective chart review. Clozapine was titrated over an average of 3 to 5 weeks up to a dose of 500 to 600 mg/day. Psychopathology was assessed with the Brief Psychiatric Rating Scale and the Clinical Global Impressions scale.

RESULTS

A clinically significant weight gain occurred mostly during the first 6 to 12 months, but continued well into the third year of treatment. Weight gain and treatment response were not correlated, and early weight gain was not a predictor of response. The cumulative incidence of patients becoming substantially overweight exceeded 50%. Being underweight at baseline correlated with maximum amount gained (p = .000), and being overweight at baseline correlated with percentage above ideal weight (p = .006).

CONCLUSION

Treatment with clozapine is associated with a high incidence of substantial weight gain, posing a potential long-term health risk. Studies are needed of the underlying mechanisms of weight gain, as well as the treatment for this side effect.

Predictors of response to clozapine

Clinical and biological measures were examined for their relationship to clinical response to clozapine. Associations were found between therapeutic response and the following variables: male gender, paranoid schizophrenia subtype diagnosis, older age at onset of illness, shorter duration of illness, higher levels of pretreatment acute EPS, low pretreatment CSF HVA/5-HIAA, greater decrease in prolactin (PRL) and increase in growth hormone (GH) response to apomorphine stimulation pretreatment and greater inhibition by clozapine treatment of PRL and GH response to apomorphine, and plasma clozapine levels above 350 ng/mL. These results are consistent with other investigators' findings and have practical and heuristic implications for the use of clozapine and understanding its mechanism of action.

5-Aryl-3-(alkylthio)-4H-1,2,4-triazoles as selective antagonists of strychnine-induced convulsions and potential antispastic agents

Selected examples from three series of isomeric (alkylthio)-1,2,4-triazoles were prepared and examined for anticonvulsant activity versus strychnine-, maximal-electroshock-, pentylenetetrazole-, and 3-mercaptopropionic-acid-induced seizures in mice. A number of 5-aryl-3-(alkylthio)-4H-1,2,4-triazoles were selective antagonists of strychnine-induced convulsions. The isomeric 3-aryl-5-(alkylthio)- and 5-aryl-3-(alkylthio)-1H-1,2,4-triazoles were essentially inactive as anticonvulsants. The most potent antagonist of strychnine-induced convulsions was 5-(2-fluorophenyl)-4-methyl-3-(methylthio)-4H-1,2,4-triazole (3s), while the most selective antagonist was 5-(3-fluorophenyl)-4-methyl-3-(methylsulfonyl)-4H-1,2,4-triazole (3aa). The anticonvulsant profiles of these 4H-1,2,4-triazoles suggested that they were acting functionally like glycine receptor agonists. Since it has recently been postulated that compounds possessing glycine-agonist-like properties might be useful in the treatment of spasticity, we examined 5-phenyl-4-methyl-3-(methylsulfonyl)-4H-1,2,4-triazole (3c) in an in vivo model of spasticity. In this regard, 3c reduced the occurrence of hyperreflexia in rats that had received spinal transections 5-10 weeks previously. While triazole 3c appeared to possess glycine-agonist-like properties in vivo, it did not displace [3H]strychnine binding from rat brain stem/spinal cord membranes in vitro. On the other hand, 3c enhanced muscimol-stimulated 36Cl influx in a rat cerebellar membrane preparation, indicating a possible interaction of these triazoles with the GABAA receptor.

The effect of activation procedures on neuroleptic-induced akathisia

Two studies have been performed to evaluate the effect of activation tasks on neuroleptic-induced akathisia (NIA). In the first sample (30 patients) we found a consistent increase of symptoms during mental activation while motor activation led to a decrease. In a second study 34 patients with the same diagnosis were evaluated, using slightly different statistical procedures: while the effects of motor activation were corroborated, mental activation did not change NIA. Since mental and motor activation are usually considered to increase tardive dyskinesia and Parkinsonism, these measures might be helpful in differentiating NIA from other antipsychotic-induced movement disorders.

Polydipsia and tardive dyskinesia in chronic psychiatric patients--related disorders?

Dopamine supersensitivity, presumably playing a role in tardive dyskinesia, has been implicated in the unexplained polydipsia occurring in chronic psychiatric patients. To investigate this hypothesis, the authors compared laboratory measurements indicating the fluid status of 65 patients before and after the development of tardive dyskinesia. No evidence was found that patients who develop tardive dyskinesia concurrently develop abnormalities in fluid regulation.

Newer antipsychotic drugs. A review of their pharmacology and therapeutic potential

Despite the enormous benefits provided by antipsychotic medication in the management of schizophrenia, available compounds have serious limitations. Firstly, they are not always effective. Secondly, positive psychopathological symptoms may benefit more than negative or deficit symptoms. Thirdly, antipsychotics are generally associated with a variety of neurological adverse effects. Three drugs have recently been or are close to being introduced into widespread clinical use: clozapine, risperidone and remoxipride. Each of these compounds appears to have some advantages over traditional antipsychotic agents, particularly in terms of reduced propensity to induce adverse neurological effects. All three drugs have been shown to be clinically effective in large scale trials. Future clinical trials are required to establish their relative merits in comparison with one another.

Does clozapine cause tardive dyskinesia?

BACKGROUND

The authors attempted to determine if chronic exposure to clozapine can cause tardive dyskinesia.

METHOD

Twenty-eight schizophrenic or schizoaffective patients with no prior history of definite tardive dyskinesia were treated with clozapine for at least 1 year, and their ongoing modified Simpson Dyskinesia Scale ratings were analyzed. These data were then compared with those of another group of similarly diagnosed patients who were treated with a conventional neuroleptic for at least 1 year.

RESULTS

Two patients in the clozapine-treated group (both of whom had ratings of questionable tardive dyskinesia at baseline) were later rated by the modified Simpson Dyskinesia Scale as having mild tardive dyskinesia on at least two consecutive ratings 3 months apart. Although there was uncertainty about whether clozapine definitely caused the tardive dyskinesia in those two patients, a survival analysis comparing the clozapine-treated group with the neuroleptic-treated group showed a lower risk of tardive dyskinesia developing in the clozapine-treated group.

CONCLUSION

This study was unable to definitively conclude whether clozapine causes tardive dyskinesia. However, if cases do develop, the risk of tardive dyskinesia is likely to be less with clozapine than with typical neuroleptics.

Brainstem frequency-following responses and cortical event-related potentials during attention

Human brainstem frequency-following responses (FFRs) and cortical event-related potentials (ERPs) were evoked by a low-frequency (230 Hz) tone during directed attention. ERPs showed significant amplitude differences consistent with expected attention effects, viz., largest to attended stimuli and smallest to ignored stimuli. The ERP data thereby confirm that attention effectively modulated cortical responses. The FFR, however, did not differ between conditions. The present results agree with one earlier FFR study and a majority of studies using click stimuli to elicit the brainstem auditory evoked response (BAER). However, several BAER studies and two recent FFR studies have shown that attention can influence human brainstem responses. The present results are therefore interpreted in the context of specific task requirements that optimize early selective attention effects.

Diabetes and development of tardive dyskinesia

Diabetes mellitus has been identified as a possible risk factor for tardive dyskinesia. The authors examined 160 elderly individuals who were beginning neuroleptic treatment; 24 had diabetes and 136 did not. After 43 weeks of neuroleptic exposure, the cumulative incidence rates of tardive dyskinesia were 54.1% (SE = 5.6%) for the diabetics and 25.6% (SE = 16.1%) for the nondiabetics.

Dose response of prophylactic antipsychotics

A review of the literature concerning the use of oral and depot antipsychotic medication has high-lighted some important considerations in the treatment of chronic schizophrenic patients. All patients not treated with any form of antipsychotic drug will relapse within 3 years. These relapses will be more clinically significant and will occur at greater frequency than in patients who receive medication on a regular basis. Careful consideration should be given to each patient when choosing between oral or depot medication and inpatient or outpatient therapy. In addition, the clinician should consider the dosage schedule of each medication and balance this against the probability of extrapyramidal side effects and noncompliance. One option for the prevention of relapse without an increase in adverse side effects is the administration of depot haloperidol. For all therapeutic options, medication should be given on a regular basis, since intermittent dosing strategies do not work, and psychosocial rehabilitation should be initiated.

Possible predictors of neuroleptic-resistant schizophrenic relapse: influence of negative symptoms and acute extrapyramidal side effects

The relative efficacy of conventional treatment alternatives that are routinely used to treat acutely relapsed schizophrenic patients who have failed an initial course of standard neuroleptic therapy has not been adequately studied, nor have predictors of poor treatment response been reliably identified. We have recently reported preliminary findings that suggest that these patients may subsequently fail to respond to such conventional alternative treatments as (1) maintaining the same dose of the neuroleptic over an extended trial, (2) significantly increasing the dose of the same neuroleptic, or (3) switching to a different class of neuroleptic. Negative symptoms and acute extrapyramidal side effects (EPS) evident during the initial treatment trial were associated with a less favorable clinical response to neuroleptic treatment. We now report on the association between clinical response and negative symptoms and acute EPS. Present findings suggest that a particular degree of negative symptoms apparent prior to treatment may be associated with a poor subsequent treatment response and that negative symptom scores and EPS ratings demonstrate a significant correlation with severity of psychiatric ratings during the treatment trial. The relationship among neuroleptic resistance, negative symptoms, and acute EPS requires further study.