Experience with clozapine in a community mental health care setting

BACKGROUND: Clozapine has been heralded as the first major breakthrough in antipsychotic drug therapy for treatment-resistant schizophrenia in 40 years. This study reports on the experience with clozapine in an outpatient, community mental health care setting. METHODS: All clinic patients receiving clozapine during the 4-year period 1992 to 1996 were retrospectively studied. Measures of improvement were changes in the Clinical Global Improvement (CGI) Scale and reduction in the number of hospital days after clozapine therapy. RESULTS: Testing with the CGI scale showed moderate or marked improvement in 63% of patients. Hospital days dropped from 7,919 to 1,833 for comparable time periods. Clozapine therapy had to be discontinued in only 21% of patients, and no serious side-effects occurred. CONCLUSION: Clozapine is an effective medication for treatment-resistant schizophrenia and can be safely used in chronic mental illness. Although the drug is expensive, the cost is offset by a remarkable reduction in hospital days.     

Effects of switching inpatients with treatment-resistant schizophrenia from clozapine to risperidone

A prospective, open-label study in a 400-bed state psychiatric hospital evaluated change in therapeutic response among ten patients with treatment-resistant schizophrenia who were switched from clozapine to risperidone. Drug effects were examined before discontinuation of clozapine and at three, six, nine, and 12 weeks of risperidone treatment. No patients improved, and five discontinued treatment due to exacerbation of psychosis or adverse effects. Changes in scores on the Positive and Negative Syndrome Scale, the Brief Psychiatric Rating Scale, and the Barnes Akathisia Scale indicated clinically significant worsening of symptoms. The findings do not support replacing clozapine with risperidone for patients with treatment-resistant schizophrenia.     

Therapeutic implications of microglia activation by lipopolysaccharide and reactive oxygen species generation in septic shock and central nervous system pathologies: a review

OBJECTIVE: Olanzapine, a potent 5-HT2a/2c, dopamine D1D2D4 antagonist with anticholinergic activity, has a profile of known receptor affinity similar to that of clozapine. This pilot study examined the efficacy of olanzapine for treatment-refractory childhood-onset schizophrenia in eight patients who had received 8-week open-label trials. For comparison, data are included from 15 patients who had received 6-week open-label clozapine trials using identical rating instruments (largely by the same raters) in the same treatment setting. METHOD: Twenty-three children and adolescents with an onset of DSM-III-R schizophrenia by age 12 for whom at least two different typical neuroleptics had been ineffective participated in the two separate studies. Some of the patients were intolerant of clozapine, although it had been effective (n = 4). Patients receiving olanzapine were evaluated over 8 weeks with the Brief Psychiatric Rating Scale (BPRS), the Scale for the Assessment of Positive Symptoms, the Scale for the Assessment of Negative Symptoms, and the Clinical Global Impressions Scale for Improvement. RESULTS: For the eight patients who received olanzapine trials, at week 8 there was a 17% improvement in the BPRS total score, a 27% improvement in the Scale for the Assessment of Negative Symptoms, and a 1% improvement in the Scale for the Assessment of Positive Symptoms, relative to "ideal" admission status on typical neuroleptics. In contrast, the magnitude of the effect sizes for each of the clinical ratings was larger at week 6 of the previous clozapine trial than for an 8-week olanzapine trial, relative to admission status on typical neuroleptics. For the four children who had received both clozapine and olanzapine, BPRS total scores were significantly lower at week 6 of clozapine treatment compared with week 6 of olanzapine treatment (p = .03). CONCLUSION: These data provide preliminary evidence for the efficacy of olanzapine for some children and adolescents with treatment-refractory schizophrenia, but they also suggest the need for a more rigorous double-blind comparison of these two atypical antipsychotics.     

Different side effect profiles of risperidone and clozapine in 20 outpatients with schizophrenia or schizoaffective disorder: a pilot study

OBJECTIVE: The purpose of this study was to compare the side effect +profiles of clozapine and risperidone. METHOD: The subjects were 20 outpatients with schizophrenia or schizoaffective disorder who were clinically stable on a regimen of clozapine at the time of screening. They underwent a randomized-order crossover comparison of 6 weeks of risperidone treatment and 6 weeks of clozapine treatment. Clinical and neurocognitive variables were assessed by raters blind to medication status, and severity of side effects was determined from patients' self-reports. RESULTS: Side effect measures, but not clinical ratings, were significantly different after 6 weeks of treatment with the two drugs. Patients required more benztropine for motor effects and complained of more insomnia with risperidone and more sedation with clozapine. Body weight was higher at the end of clozapine treatment than at the end of risperidone treatment. CONCLUSIONS: In this exploratory study, the side effect profiles of clozapine and risperidone were consistent with the different pharmacodynamic profiles of the two drugs.     

Time to clozapine response in a standardized trial

OBJECTIVE: The authors sought to determine the time to clozapine response in treatment-refractory patients with schizophrenia. METHOD: Antipsychotic response to a clozapine trial was examined in 50 treatment-refractory schizophrenic inpatients. Subjects were treated with clozapine for at least 12 months, regardless of response status, according to a standardized, increasing dose protocol. Behavioral changes were measured through monthly assessments with the Brief Psychiatric Rating Scale. RESULTS: Thirty-four subjects (68%) met clinical response criteria by the end of the trial. Response was achieved at a mean dose of 468 mg/day (SD = 168). The dose of 30 (88%) of the responding patients was 600 mg/day or less. The mean time to response was 82 days (SD = 100, range = 10-401). It took an average of 60 days (SD = 87) for subjects to reach the dose at which clozapine response was achieved. Once this dose was reached, the average response time was 17 days (SD = 14, range = 2-56). All 34 subjects who responded met criteria within 8 weeks of a clozapine dose escalation. No late response was found in the remaining 16 subjects despite a mean follow-up period of 75 weeks (SD = 50). CONCLUSIONS: In this study, all patients who responded to clozapine did so within 8 weeks of a change in dose. Thus, there appears to be little clinical gain in prolonging exposure to clozapine beyond 8 weeks at any particular dose if no response is seen.     

Risperidone as an adjunct to clozapine therapy in chronic schizophrenics

BACKGROUND: Some treatment-resistant schizophrenic patients improve enough to remain out of the hospital but continue to have significant positive or negative symptoms. METHOD: The goal of this study was to assess the safety and potential efficacy of risperidone as an adjunct for schizophrenic patients treated with clozapine. In an open 4-week trial involving 12 DSM-III-R-diagnosed patients, the addition of risperidone to clozapine was well tolerated and did not affect serum clozapine concentrations significantly. RESULTS: Total Brief Psychiatric Rating Scale (BPRS) scores and subscales measuring positive symptoms, negative symptoms, and depressive symptoms were significantly reduced from baseline. Ten of 12 participants had a 20% or greater reduction in the total BPRS score. CONCLUSION: In this open trial, the addition of risperidone to clozapine was well tolerated and produced significant reduction of symptoms, suggesting that this may be a useful clinical approach. Because this was an open trial, the improvement we observed must be replicated in a controlled trial.     

Relationship between clinical efficacy and clozapine concentrations in plasma in schizophrenia: effect of smoking

Concentrations in plasma of clozapine and norclozapine, the major metabolite of clozapine, were measured in 59 treatment-resistant schizophrenic patients at a random time period during the course of treatment. A lower sum of the concentrations of clozapine and norclozapine or either alone predicted less improvement in the Brief Psychiatric Rating Scale (BPRS) Total and Positive symptoms in a multivariate analysis that controlled for baseline BPRS rating and dose. The mean doses of clozapine after 6 months of treatment and at the time of blood sampling were not significantly different in 30 responders and 29 nonresponders to clozapine, on the basis of the decrease in BPRS Total scores, whereas the concentrations in plasma in clozapine of norclozapine and the sum of their concentrations were significantly higher in responders. Clozapine and norclozapine concentrations in plasma correlated both with dose at the time of sampling and with dose at 6 months. A clozapine concentration of 370 ng/ml was the optimal cutoff for distinguishing responders from nonresponders. Clozapine and norclozapine concentrations did not differ in male smokers and nonsmokers.     

The expanding indications for clozapine.

Clozapine is increasingly being used for clinical indications in addition to treatment-resistant schizophrenia; this article reviews the relevant literature. The first section reassesses the risks associated with clozapine treatment, particularly agranulocytosis. The next section discusses its use for schizophrenia in patients who are treatment resistant, not treatment resistant, and intolerant of traditional drug treatments. Subsequent sections address its use in mood disorders, neurologic conditions, comorbid substance abuse, aggressive behavior, and childhood schizophrenia. Each includes the initial rationale for the use of clozapine in the disorder, a critical evaluation of the relevant literature, and theories as to why clozapine's unique pharmacodynamic profile may be efficacious for the specific condition. This body of literature suggests clozapine may be an effective treatment for a wide range of disorders. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Can low-dose clozapine pharmacokinetics predict steady-state plasma concentration?

Plasma concentrations of clozapine at a given dose vary considerably between patients, but drug levels are not routinely monitored during the normal 4- to 8-week dose escalation period at the beginning of therapy. We hypothesized that the dose required to give a putative threshold therapeutic concentration of 350 micrograms/L could be individualized using pharmacokinetic predictions made at the beginning of normal dose escalation. Low-dose clozapine (25-75 mg every 12 h) was administered to 21 treatment-resistant patients with schizophrenia who had been split into three groups. In group A (six patients), individual target doses were predicted from area under the concentration-time curve data after a single 50-mg dose. In group B (five patients), predictions were made as in group A but at steady state. In group C (10 patients), predictions were based on trough clozapine levels obtained at steady state immediately before dose increase. Dosage was increased, if tolerated, by 25 mg twice daily three times a week for 4-8 weeks according to established clinical practice. Clozapine concentrations were measured weekly, and actual target doses were determined for each patient from dose-concentration plots. In groups A and B, the correlation between actual and predicted target dose was not significant (r = 0.18, p = 0.59). In group C, however, it was significant (r = 0.86, p = 0.0016). These results suggest that individualized doses of clozapine for treatment-resistant patients with schizophrenia can be conveniently predicted from trough drug levels at the start of therapy. Such information would facilitate a more rapid, individualized, and consistent attainment of therapeutic doses than is now the case in clinical practice.     

Prediction of short-term changes in symptom severity by baseline plasma homovanillic acid levels in schizophrenic patients receiving clozapine

The relationship between pretreatment levels of plasma homovanillic acid (pHVA) and the outcome of clozapine treatment was studied in 18 male patients with schizophrenia who were resistant to treatment with conventional neuroleptics. After 6 months of clozapine treatment, 7 patients demonstrated > or = 20% decrease in the Brief Psychiatric Rating Scale (BPRS) (responders), while 11 patients did not (non-responders). Responders and non-responders did not differ with respect to the baseline pHVA level. The BPRS Positive Symptom scores at 6 weeks and 3 months, but not those at baseline and 6 months, following initiation of clozapine treatment negatively correlated with pHVA levels for all patients. The correlations became stronger when only responders were included. No significant correlation between Positive Symptom scores and pHVA levels was observed for non-responders. The BPRS Total and Negative Symptom scores did not correlate with pHVA for all patients, responders or non-responders at any time. The percent decrease in the BPRS Positive Symptom scores from baseline at 6 weeks following clozapine treatment correlated significantly with pHVA levels in responders. These results suggest that pretreatment levels of pHVA can be used to predict relatively short-term changes in the positive symptoms of patients with schizophrenia receiving clozapine treatment, particularly for clozapine responders.     

Correlated changes in symptoms and neurotransmitter indices during maintenance treatment with clozapine or conventional neuroleptics in adolescents and young adults with schizophrenia

A study of 40 young patients (age 14-22 years) with DSM-III-R schizophrenia (without substance abuse) was conducted following a mean of 3.4 years of neuroleptic treatment. After failing on conventional agents in clinical trials lasting a mean of 2 years, 20 patients were prospectively maintained on open-label clozapine (mean 324 mg daily), and another 20 patients continued on typical neuroleptics (mean 465 mg chlorpromazine-equivalents daily). Patients were then sampled for biochemical measures and assessed for psychopathology (Brief Psychiatric Rating Scale, Scales for the Assessment of Positive/ Negative Symptoms) on six occasions at consecutive 6-week intervals-during maintenance treatment on clozapine or conventional neuroleptics. There were 22-fold interindividual differences in clozapine levels and also high intraindividual differences over time. Maintenance dosage was linearly related to plasma levels of clozapine and its metabolites. Prolactin levels were elevated with typical neuroleptics but not clozapine. Blood levels of serotonin, methoxyhydroxyphenylglycol (MHPG), norepinephrine, and epinephrine (but not dopamine) were significantly higher in clozapine-treated patients than in conventionally treated patients. Higher serotonin levels were associated with significantly fewer negative symptoms, whereas higher MHPG levels were correlated with less depression. These findings suggest involvement of norepinephrine and serotonin in the pathophysiology of schizophrenia (with depression associated with lower MHPG levels and negative symptoms associated with lower serotonin levels) and in the therapeutic actions of clozapine. Speculatively, a treatment strategy of targeting specific neurotransmitter systems might be based on the presence of specific symptoms in adolescents and young adults with schizophrenia.     

Clinical and neurocognitive effects of clozapine and risperidone in treatment-refractory schizophrenic patients: a prospective study

BACKGROUND: Few controlled studies have compared the efficacy of clozapine and risperidone in treatment-refractory schizophrenic patients. The present study investigates the efficacy of both clozapine and risperidone on psychopathologic and neurocognitive measures in a prospective 12-week open-label trial in treatment-refractory schizophrenic patients from state psychiatric hospitals. METHOD: Thirty-five DSM-IV schizophrenic patients with a documented history of nonresponse to typical neuroleptics were treated with either clozapine or risperidone. Response was assessed every 2 weeks by independent raters with the Positive and Negative Syndrome Scale (PANSS), the Clinical Global Impressions (CGI) scale, neurologic rating scales, and plasma drug levels. Neurocognitive tests were administered at baseline and week 12. RESULTS: Both clozapine and risperidone brought about significant (p < .003) overall improvement in psychopathology. However, clozapine was numerically superior to risperidone on PANSS total scores and PANSS positive, negative, excitement, and cognitive factors. Extrapyramidal side effects were minimal for clozapine, whereas some were present for risperidone. Patients taking risperidone improved significantly in the beginning stages of the study and remained stable thereafter. Patients taking clozapine showed a gradual improvement that occurred over the entire length of the trial. Neurocognitive measures showed minimal improvement and did not differentiate between the 2 medication groups. CONCLUSION: Both clozapine and risperidone were comparably effective across a wide spectrum of psychopathologic measures. While the efficacy of clozapine was only numerically superior to that of risperidone, it was associated with fewer extrapyramidal side effects and with progressive improvement over the 12-week treatment period, suggesting that in longer trials clozapine may prove to be superior to risperidone in neuroleptic-refractory patients.     

A new taxane diterpenoid from Taxus mairei

OBJECTIVE: The authors examined the effect of prolonged clozapine treatment on central serotonergic (5-HT) function in schizophrenia. METHOD: Prolactin responses to the 5-HT releasing agent d-fenfluramine were measured in two groups of 10 schizophrenic subjects. The first group was tested twice, before and after a mean of 10 weeks of clozapine treatment. The second group was tested after a mean of 20 months of clozapine treatment. RESULTS: The prolactin response was significantly blunted in these 20 patients treated with clozapine. There was a significant positive correlation between d-fenfluramine-evoked prolactin release and the overall positive symptom score and the hallucination and delusion subscores of the Scale for the Assessment of Positive Symptoms. CONCLUSIONS: Blunted 5-HT-mediated prolactin responses in schizophrenic patients receiving clozapine monotherapy for up to 20 months were correlated with reductions in positive symptoms. This suggests that 5-HT antagonism is relevant to clozapine's efficacy in alleviating hallucinations and other positive schizophrenic symptoms.     

Electrophoretic mobility of five polypeptides using nine different capillary chemistries over the pH range of 3.5-6.5

Clozapine has been shown to have superior effectiveness compared with classic neuroleptics in treating refractory schizophrenia in Caucasians, but its efficacy and safety in Chinese have not been adequately studied. Forty Chinese schizophrenic patients were recruited in a 12-week, double-blind, comparative trial. Twenty-one patients were randomly assigned to clozapine treatment and 19 to chlorpromazine treatment. The average dose was 543 +/- 157 and 1163 +/- 228 mg/day for clozapine and chlorpromazine, respectively. The results showed that six clozapine-treated patients (28.6%) had more than 20% improvement in Brief Psychiatric Rating Scale score and were classified as responders, whereas none of the chlorpromazine-treated patients was classified as a responder. The degree of improvement in positive symptoms, negative symptoms and Brief Psychiatric Rating Scale scores in the clozapine group was inversely correlated with the severity of negative symptoms at entry into the trial. Two clozapine-treated patients were withdrawn from the study, one because of leukopenia and nausea, and the other because of vomiting and hypotension. Chlorpromazine treatment was prematurely discontinued in two patients, because of jaundice and over sedation in one, and because of severe weight loss in the other (9 kg). The rate of moderate-to-severe sialorrhea was high in clozapine-treated patients (28.6%). Two clozapine-treated patients and two chlorpromazine-treated patients showed significant improvement in previously existing tardive dyskinesia and one chlorpromazine-treated patient exhibited aggravation of tardive dyskinesia. The results of this study indicate that clozapine treatment might have advantages over chlorpromazine for Chinese schizophrenic patients who are refractory to typical neuroleptic treatment.     

How to spot depressed patients in your practice

The relationships between clozapine dosages, plasma concentrations, and clinical responses in Chinese schizophrenics were studied. Fourteen treatment-refractory schizophrenic patients were treated with clozapine for 12 weeks. Patients were assessed before and after 6 and 12 weeks of treatment using the Brief Psychiatric Rating Scale (BPRS), the Clinical Global Impression (CGI), and the Simpson-Angus Scale for Extrapyramidal Side Effect. Plasma clozapine concentrations were determined by high-performance liquid chromatography. Ten patients (71.4%) responded after 12 weeks of treatment. Although the mean daily dosage at week 12 (373 +/- 90 mg/day) was lower than that reported in American trials (444 mg/day), the mean plasma clozapine concentration attained (1,078 +/- 385 ng/ml) was higher. This higher concentration may be due to the lower body wight and the preponderance of women among our patients, absence of smoking and alcohol use, and/or ethnic difference between Chinese and non-Chinese. There was wide interindividual variation in the plasma clozapine concentrations. Compared with other studies, the plasma clozapine concentrations and the response rate were higher. Although the sample size was small, the findings are suggestive of pharmacokinetic and pharmacodynamic ethnic differences in Chinese with clozapine therapy.     

Clozapine and risperidone in chronic schizophrenia: effects on symptoms, parkinsonian side effects, and neuroendocrine response

OBJECTIVE: Clozapine and risperidone were the first two "second-generation" antipsychotic drugs approved for schizophrenia. There is currently little information about their comparative efficacy from head-to-head clinical trials. The purpose of this study was to examine the comparative efficacy of clozapine and risperidone for positive and negative symptoms, depression, parkinsonian side effects, and indexes of neuroendocrine function in schizophrenic patients who met a priori criteria for partial response to traditional neuroleptic agents. METHOD: After a baseline fluphenazine treatment period, 29 patients participated in a 6-week, double-blind, parallel-group comparison of the effects of these agents. RESULTS: Clozapine was superior to risperidone for positive symptoms and parkinsonian side effects, but there were no significant differences between the drugs on two measures of negative symptoms, Brief Psychiatric Rating Scale total scores, and depression scores. The clozapine patients, but not the risperidone patients, demonstrated significant reductions from the fluphenazine baseline in positive symptoms, total symptoms, and depression. In addition, clozapine produced fewer effects on plasma prolactin than risperidone or fluphenazine. The mean daily doses during week 6 of the trial were 403.6 mg of clozapine and 5.9 mg of risperidone. CONCLUSIONS: The findings from this study indicate that these drugs have both important differences and similarities in their comparative efficacy in chronically ill, partially responsive patients with schizophrenia. Further research on second-generation antipsychotic drugs in this patient population that addresses key methodological issues, such as optimal dose and treatment duration, are needed.     

The effect of clozapine on preexisting tardive dyskinesia

Since the 1950s, the main treatment for schizophrenia has been the use of neuroleptic therapy. However, these medications may produce tardive dyskinesia in those patients who require prolonged neuroleptic treatment. With the advent of clozapine, patients with preexisting tardive dyskinesia began therapy and their symptoms did not worsen--and, in many cases, their symptoms improved dramatically. In this study, the mean Abnormal Involuntary Movement Scale (AIMS) scores from baseline to 6 months are compared for 12 patients in a private partial hospitalization program for schizophrenia. The findings reveal a drastic decrease in AIMS scores after 1 month of clozapine therapy and a steady decrease in scores throughout the 6 months of analysis.     

Immunohistochemistry diagnosis of fungal infections

BACKGROUND: A potential beneficial outcome of treatment with certain of the atypical neuroleptics is the reduced risk of cognitive impairment, stemming from purported low affinity for cholinergic receptors. In vitro experiments have shown that clozapine is highly anticholinergic and risperidone is minimally so. In vivo tests of the anticholinergic burden imposed by these medications and its potential cognitive consequences are needed. This study examines anticholinergic burden in schizophrenia patients taking clozapine and risperidone and tests whether this burden is associated with cognitive deficits. METHOD: Serum anticholinergic levels were determined in a sample of 22 chronic schizophrenia patients using the radioreceptor assay method of Tune and Coyle (1980). Fifteen patients received clozapine; 7 received risperidone. Mean +/- SD age of the sample, comprising 12 men and 10 women (68% white), was 44.7 +/- 8.4 years. Mean +/- SD age at onset of schizophrenia illness was 23.5 +/- 7.4 years. Two anticholinergic assays based on blood samples collected 1 week apart were available on each patient. RESULTS: Data indicated that clozapine patients had significantly (p < .001) higher anticholinergic levels at both collection points, and levels for both drugs remained stable over time. The clozapine and risperidone patients had essentially equivalent scores on the cognitive measure. CONCLUSION: These data suggest that anticholinergicity distinguishes clozapine and risperidone in vivo but that this effect is not associated with differences in global cognitive functioning. Results suggest that clozapine, despite producing moderately high in vivo serum anticholinergic levels, still holds clinical advantage over standard neuroleptics in terms of cognitive side effects. Reasons for this lowered risk of cognitive impairment are discussed.     

Response of patients with treatment-refractory schizophrenia to clozapine within three serum level ranges

OBJECTIVE: This study sought to determine the relationships between serum clozapine levels and therapeutic response. METHOD: Fifty-six inpatients who met the DSM-III-R criteria for chronic schizophrenia and who had not responded to extended treatment with classical antipsychotics were randomly assigned to 12 weeks of double-blind treatment with clozapine at one of three serum level ranges: low (50-150 ng/ml), medium (200-300 ng/ml), or high (350-450 ng/ml). Baseline clinical assessments were completed before the patients' regular antipsychotic and anticholinergic drugs were discontinued. During clozapine treatment, serum levels were ascertained weekly to allow adjustment of clozapine doses so as to maintain each patient near the midpoint of his or her assigned serum level range. Clinical assessments were completed after 6 and 12 weeks of treatment. RESULTS: The analyses of the results of treatment supported the superior efficacy of the 200-300 ng/ml and 350-450 ng/ml serum clozapine level ranges over the 50-150 ng/ml range, with no advantage for 350-450 ng/ml over 200-300 ng/ml. Sleepiness increased with increasing serum levels. CONCLUSIONS: Serum clozapine levels per unit of daily dose were at the lower end of the range noted in previous reports, possibly reflecting the current study's dosing schedules of twice or three times a day, the 11- to 13-hour postdose sampling time, and the moderate doses given. Serum clozapine levels, if interpreted in relation to daily clozapine dosing schedules, postdose sampling time, and total daily dose, may help to guide dosing to provide adequate opportunities for therapeutic response and to limit certain side effects of clozapine treatment.     

A novel TP53 splicing mutation in a Li-Fraumeni syndrome family: a patient with Wilms'' tumour is not a mutation carrier

The authors describe the case of a patient with treatment-resistant schizophrenia who became pregnant after switching from conventional neuroleptic medications to clozapine, an atypical antipsychotic medication that does not cause hyperprolactinemia. Gestational diabetes, possibly exacerbated by clozapine, complicated management of her pregnancy. Comprehensive community support and psychiatric rehabilitation, combined with a positive response to clozapine, contributed to satisfying the patient's goal of having a healthy baby and being able to take the baby home to live with her and her husband.