Reason for clozapine cessation

Overcoming clozapine's adverse events: a narrative review of systematic reviews and meta-analyses

INTRODUCTION

Clozapine is the gold standard treatment for treatment-resistant schizophrenia, however adverse events remain a clinical challenge.

AREAS COVERED

This review presents a narrative synthesis of systematic reviews and meta-analyses that have reported the onset, incidence, prevalence, and management of clozapine's adverse events. We conducted a systematic literature search using PubMed, Embase, PsycINFO, OvidMEDLINE, CINAHL, and the Cochrane Database of Systematic Reviews from inception to April 2024.

EXPERT OPINION

Effective management of clozapine's adverse events necessitates multi-faceted, individualized, and shared-decision strategies. Despite a lack of high-quality systematic evidence, expert inter-disciplinary solutions are provided to help address a critical need for clinical guidance. This 35-year update offers an evidence-based framework to assist clinicians, patients, and caregivers navigate the adverse events associated with clozapine therapy.

Clozapine and neutrophil response in patients of African descent: A six-month, multinational, prospective, open-label clinical trial

INTRODUCTION

Clozapine is the most effective antipsychotic for treatment-resistant schizophrenia, but it is markedly underutilized, particularly in the US Black population, partly because of concern over clozapine-associated low absolute neutrophil count (ANC). People of African descent have a lower normative ANC range than the White population, which is associated with a specific "ACKR1-null" ("Duffy null") CC genotype (SNP rs2814778) on the ACKR1 gene, termed benign ethnic neutropenia (BEN). The range of ANC variability and safety of clozapine have not been established in people with BEN or examined prospectively in people of African descent.

METHODS

We completed a multisite, 6-month, prospective, open-label clinical trial of clozapine treatment in people of African descent with schizophrenia spectrum disorders for whom clozapine was clinically indicated, with or without the ACKR1-null genotype. We examined clozapine safety and weekly ANC during clozapine treatment and evaluated ANC variability by ACKR1-null genotype, sex, study site, and clozapine dosing using repeated measures analysis of covariance. Genotype was assayed using TaqMan® technology.

RESULTS

We enrolled 274 participants, of whom 227 (82.8 %) completed 6 months of clozapine treatment. There was one case of severe neutropenia (<500 cells/mm3) (0.36 %) over 1467.6 person-months of clozapine exposure. This participant recovered without sequelae after discontinuation of clozapine. Of the 249 participants with known genotypes, 199 (79.9 %) had the ACKR1-null genotype. Neutropenia (<1500 cells/mm3) occurred significantly more often in the ACKR1-null group (33 % [65/199]) than in those with the T allele (6 % (3/50); p < 0.001). Fourteen (5 %) patients discontinued due to adverse events. Rates of infection and fever were low and sialorrhea was the commonest side effect (N = 187, 68 %).

CONCLUSION

To our knowledge, this is the largest prospective clozapine trial in people of African descent. Severe neutropenia was rare, despite the high prevalence (80 %) of the ACKR1-null genotype. Our findings suggest that clozapine can be used safely in Black patients including those with BEN.

Evaluation of major adverse events of clozapine based on accordance to an international titration guideline

Introduction

Clozapine is the only antipsychotic approved for treatment-resistant schizophrenia, but without appropriate monitoring, it can be associated with potentially fatal outcomes. An International Adult Clozapine Titration Guideline categorizes patients into normal or slow metabolizers. Categorization provides clozapine titration schedules and recommends regular c-reactive protein (CRP) and clozapine concentration monitoring to reduce the risk of adverse drug reactions (ADRs). The impact of the guideline on clozapine ADRs has not been evaluated.

Methods

A retrospective chart review assessed clozapine titrations, laboratory monitoring, ADRs, and discontinuations for clozapine-naive adult inpatients at a single center from January 1, 2013, to June 1, 2022. Each patient's cumulative weekly clozapine dosage was compared with their guideline recommended dosage to create a percent accordance. Linear logistic regression evaluated the relationship between titration speed and the presence of an ADR, while descriptive statistics analyzed laboratory monitoring.

Results

Forty-three patients were included, with the majority being White males with schizophrenia. An inverse relationship existed between the last inpatient week clozapine dose percent accordance and the probability of an ADR. Nonobese patients were less likely than obese patients to experience an ADR (odds ratio = 0.17; 95% CI, 0.03-0.99). CRP and clozapine concentration monitoring was suboptimal.

Discussion

Based on our small retrospective review of primarily White males, more aggressive clozapine titrations did not increase ADRs. Future studies with more diverse samples are needed and should focus on specific ADRs, which may have increased occurrence with rapid titrations. Obese patients were at higher risk of ADRs, correlating with the guideline-recommended slower titrations for these patients.

Patient and caregivers perspective about clozapine: A systematic review

BACKGROUND

Clozapine is a gold standard treatment for treatment-resistant schizophrenia. However, the patients' and caregivers' perception and their experience with clozapine has remained much less explored.

AIM

To review the available literature on the patients' and caregivers' attitudes, perceptions, and experiences with clozapine.

METHODOLOGY

27 original research and review articles published in PubMed-indexed journals till March 2023 in the English language, exploring the patient and/or caregiver/family member's experience with using clozapine, were included.

RESULTS

30-80 %of patients and 92-100 % of caregivers were found to have a positive attitude towards clozapine in terms of its impact on psychopathology, cognitive and social functioning of the patient, and caregiving needs. Most patients and caregivers also found that the positive effects of clozapine outweighed the side effects and distress related to repeated blood testing. However, a lack of satisfaction was noted among both patients and caregivers regarding the knowledge provided to them regarding clozapine, especially regarding its common adverse effects. Discontinuation of clozapine was found to be more commonly done by the patients' accord rather than clinicians, and the perceived side effects like hypersalivation and excessive sedation emerge as important factors that lead to discontinuation rather than the need for repeated blood testing.

CONCLUSIONS

Overall, patients and their caregivers share a positive attitude towards clozapine and perceive it to be an effective and beneficial drug, but more effort needs to be directed by the clinical teams to educate the users of clozapine regarding its complete side effect profile and provide continuous guidance about dealing with the emerging side effects throughout treatment.

[Safety aspects during treatment with clozapine. : Monitoring and rechallenge - a narrative review]

BACKGROUND

Due to its unique efficacy in treatment-resistant schizophrenia, discontinuation of treatment with clozapine is frequently associated with a significant worsening of symptoms, but also with an increased risk of suicide. Based on the literature, this review aims at summarizing different monitoring recommendations in order to be able to continue this therapy despite the occurrence of side effects. In addition, we provide recommendations when rechallenge of a previously stopped treatment with clozapine can be considered and when a definite discontinuation must take place.

MATERIAL AND METHODS

Medline, the Guideline for the use of clozapine 2013 of the Netherlands Clozapine Collaboration Group, and the S3 Guideline for Schizophrenia of the German Association of Psychiatry, Psychotherapy and Psychosomatics were searched for relevant literature, the last query dating from April 28th, 2023.

RESULTS

If agranulocytosis or cardiomyopathy develops, treatment with clozapine must be discontinued and should not be resumed thereafter. In contrast, treatment with clozapine which had to be discontinued due to myocarditis or prolongation of the QTc interval may be continued if left ventricular function is normal or after normalization of the QTc interval. Other side effects are usually not absolute contraindications for rechallenge but often require the adjunctive use of additional pharmacologic and non-pharmacologic measures.

CONCLUSION

Taking into consideration various monitoring recommendations, cessation of treatment with clozapine can often be prevented or treatment with clozapine that has been discontinued due to side effects can be resumed.

Rates and Reasons for Clozapine Treatment Interruptions: Impact of the Frequency of Hematologic Monitoring and Cardiac Adverse Events

BACKGROUND

Differing rates and reasons for interruptions of clozapine treatment have been reported globally. This article evaluated the rates and reasons for clozapine therapy interruptions in Australia and explored the impact of the frequency of hematological monitoring on these parameters.

METHODS

Data of the patients who were newly commenced on clozapine at three metropolitan public mental health services in Western Australia over 11 years were retrospectively collated. The rate and reasons for clozapine therapy interruptions and their association with the frequency of hematological monitoring, age, sex, and treatment site were analyzed using parametric, nonparametric, and correlational analyses.

RESULTS

Of the 457 patients whose data were collected, 69.6% had an interruption of treatment with 41.2% of those occurring during the period of mandatory weekly hematological monitoring in the first 18 weeks. Nonadherence (57.4%) and adverse effects (28.8%) were the 2 main reasons for the treatment interruptions. Cardiac issues accounted for the majority of the interruptions (61.8%) due to specified adverse effects, and these occurred significantly more commonly within the first 18 weeks. Location, age, and sex did not predict the possibility of treatment interruptions.

CONCLUSIONS

The high rates of clozapine treatment interruption observed during the period of weekly monitoring point toward the need to address the burden of frequent hematological monitoring for patients. Disproportionately higher rates of interruption due to cardiac adverse effects observed in this study compared with research from non-Australian settings raise the possibility of geographical differences in the adverse effects leading to treatment discontinuation.

Second to none: rationale, timing, and clinical management of clozapine use in schizophrenia

Despite its enduring relevance as the single most effective and important evidence-based treatment for schizophrenia, underutilization of clozapine remains considerable. To a substantial degree, this is attributable to a reluctance of psychiatrists to offer clozapine due to its relatively large side-effect burden and the complexity of its use. This underscores the necessity for continued education regarding both the vital nature and the intricacies of clozapine treatment. This narrative review summarizes all clinically relevant areas of evidence, which support clozapine's wide-ranging superior efficacy - for treatment-resistant schizophrenia (TRS) and beyond - and make its safe use eminently feasible. Converging evidence indicates that TRS constitutes a distinct albeit heterogeneous subgroup of schizophrenias primarily responsive to clozapine. Most importantly, the predominantly early onset of treatment resistance and the considerable decline in response rates associated with its delayed initiation make clozapine an essential treatment option throughout the course of illness, beginning with the first psychotic episode. To maximize patients' benefits, systematic early recognition efforts based on stringent use of TRS criteria, a timely offer of clozapine, thorough side-effect screening and management as well as consistent use of therapeutic drug monitoring and established augmentation strategies for suboptimal responders are crucial. To minimize permanent all-cause discontinuation, re-challenges after neutropenia or myocarditis should be considered. Owing to clozapine's unique efficacy, comorbid conditions including substance use and most somatic disorders should not dissuade but rather encourage clinicians to consider clozapine. Moreover, treatment decisions need to be informed by the late onset of clozapine's full effects, which for reduced suicidality and mortality rates may not even be readily apparent. Overall, the singular extent of its efficacy combined with the high level of patient satisfaction continues to distinguish clozapine from all other available antipsychotics.

Antipsychotic prescribing practices for outpatients with schizophrenia and reasons for non-clozapine treatment - Data from a Danish quality assessment audit

BACKGROUND

Clozapine is the gold standard for treating treatment-resistant schizophrenia (TRS) although widely underutilised. Both organisational, patient- and clinician related reasons for the underutilisation have been reported, however, the clinical impact of either in real-world settings is not fully elucidated.

AIM

This audit aimed to evaluate the local antipsychotic (AP) prescribing practices for outpatients with schizophrenia and to assess the spectrum and prevalence of journalised reasons for non-clozapine treatment amongst eligible outpatients.

METHODS

Data on demographics, current and former AP treatments, as well as documented reasons for non-clozapine treatment, was extracted through chart audit.

RESULTS

Of the 668 affiliated outpatients with schizophrenia, 43% were treated with AP polytherapy (APP) and 19.6% with clozapine. The most prevalent reason for clozapine discontinuation was related to side effects whereas the most prevalent reason for refusal or omission of clozapine treatment was related to the associated monitoring regimen.

CONCLUSIONS

This audit showed that APP prescribing is a highly prevalent practice in our services when treating outpatients with schizophrenia and that clozapine is underutilised in a 'last resort' manner. The blood-monitoring regimen associated with clozapine treatment was found to be an important factor in the underutilisation. It seemed, however, that the monitoring constituted a barrier for different reasons, requiring different approaches to remedy. Future studies, directly involving both patients and clinicians in the identification and management of the most clinically relevant barriers and their corresponding facilitators, are warranted.

Efficacy and safety of Lu AF35700 in treatment-resistant schizophrenia: A randomized, active-controlled trial with open-label extension

INTRODUCTION

Treatment resistance constitutes the highest burden of disease within schizophrenia. We hypothesized that the synergistic activity of Lu AF35700 at dopamine D1 and D2 receptors might provide superior antipsychotic effects versus first-line antipsychotic therapy in patients with treatment resistant schizophrenia (TRS), with a benign tolerability profile.

METHODS

This was a randomized, double-blind, active-controlled clinical trial (NCT02717195) followed by a one year open-label safety extension (NCT02892422). Following prospective confirmation of treatment resistance, patients were randomized (1:1:1) to 10 weeks double-blind treatment with Lu AF35700 10 mg or 20 mg, or active comparator (risperidone or olanzapine).

RESULTS

1628 patients were screened for TRS, of which 1092 entered the prospective confirmation period. Of these, 697 were randomized (Lu AF35700 10 mg n = 235, 20 mg n = 232, comparator n = 230) and 395 discontinued before randomization, including 264 (24 %) who responded to treatment. 586 patients completed the double-blind phase, of which 524 entered the open-label extension and 318 completed 1-year of open-label treatment. At the end of the double-blind phase, the mean ± SE change in positive and negative syndrome scale (PANSS) total score was -10.1 ± 0.96 for Lu AF35700 10 mg, -8.22 ± 0.98 for Lu AF35700 20 mg, and - 9.90 ± 0.97 for the comparator group. Treatment differences [95 % CI] versus comparator treatment were non-significant (-0.12 [-2.37; 2.13] and 1.67 [-0.59; 3.94], respectively). The most common adverse events with Lu AF35700 were increased weight and headache. Prolactin values decreased by ≥50 % in both sexes treated with Lu AF35700.

CONCLUSIONS

Despite evidence of antipsychotic efficacy, treatment with Lu AF35700 failed to differentiate from conventional antipsychotic treatment for patients with TRS.

Combination With Long-Acting Injectable Antipsychotics and Utilization of Nonstandard Formulations as Compliance Enhancing Methods for Clozapine Users: A Systematic Review and A Case Series

BACKGROUND

Combining clozapine with a long-acting injectable antipsychotic (LAI) or using different, nonstandard formulations of the compound may improve treatment outcomes. We aimed to investigate the utility of the clozapine-LAI combination and different formulations of clozapine for compliance problems of clozapine treatment, and to describe a case series on the combined treatment.

PROCEDURES

We conducted a PubMed search with no date restriction. The number and length of hospitalizations, the results of clinical scales, and adverse events were recorded. We also present a case series of 18 patients using the clozapine-LAI combination. Data were collected from the medical charts and electronic records.

RESULTS

We extracted 9 records describing the use of the clozapine-LAI combination. The case reports and mirror-image studies showed a significant reduction in the number of hospitalizations, length of hospital stays, and number of visits to the emergency department on the combined treatment with no serious adverse events. We included 11 articles for clozapine formulations. The case reports and retrospective data suggested that short-acting intramuscular clozapine was often well tolerated and resulted in an increased acceptance of oral clozapine in the acute phase of illness. In our case series, illness severity and the number of hospitalization per year significantly decreased after the combined treatment, besides a significant improvement in the functioning scores. Hyperprolactinemia and extrapyramidal side effects were reported due to concomitant LAIs.

CONCLUSIONS

Despite the encouraging evidence, the present data are preliminary and mostly based on retrospective studies, and oral-dissolving tablets or oral liquid formulations of clozapine have insufficient evidence for clinical practice. Well-designed, controlled, follow-up studies are needed for both clozapine-LAI combination and different formulations of clozapine.

Clozapine- and non-clozapine-associated neutropenia in patients with schizophrenia: a retrospective cohort study

INTRODUCTION

The antipsychotic drug clozapine remains underutilized partly because of the risk of life-threatening adverse effects, such as neutropenia. Therefore, an extensive hematological monitoring program was set up to detect neutropenia.

METHODS

In this retrospective cohort study, we used registry-based data from the Capital Region of Denmark to investigate incidence rates of neutropenia among patients with a diagnosis of schizophrenia or other psychotic disorders and treated with clozapine for the first time. In a within-subject design, we compared rates of neutropenia in time periods where patients were exposed to clozapine versus time periods, where they were not exposed to clozapine. We also investigated whether the lengths of clozapine-associated neutropenia (CAN) were related to discontinuation of clozapine treatment.

RESULTS

Data from 520 clozapine users were included. The incidence rate of CAN was 3.2 cases per 100 person-years (95% confidence interval [CI]: 2.1-4.8) throughout the entire study. There was no significant difference in incidence rates of neutropenia during clozapine exposure and non-clozapine exposure, with an incidence rate ratio of 0.7 (95% CI: 0.4-1.3). One episode of severe neutropenia was detected. Episodes of CAN with only one sub-threshold neutrophil count were not associated with higher clozapine discontinuation (26%) than CAN episodes of more than one sub-threshold neutrophil count (28%).

CONCLUSION

In the present study, we could not confirm that clozapine treatment was associated with neutropenia.

Reducing the Risk of Withdrawal Symptoms and Relapse Following Clozapine Discontinuation-Is It Feasible to Develop Evidence-Based Guidelines?

Clozapine is the only antipsychotic that is effective in treatment-resistant schizophrenia. However, in certain clinical situations, such as the emergence of serious adverse effects, it is necessary to discontinue clozapine. Stopping clozapine treatment poses a particular challenge due to the risk of psychotic relapse, as well as the development of withdrawal symptoms. Despite these challenges for the clinician, there is currently no formal guidance on how to safely to discontinue clozapine. We assessed the feasibility of developing evidence-based recommendations for (1) minimizing the risk of withdrawal symptoms, (2) managing withdrawal phenomena, and (3) commencing alternatives treatment when clozapine is discontinued. We then evaluated the recommendations against the Appraisal of Guidelines for Research and Evaluation (AGREE) II criteria. We produced 19 recommendations. The majority of these recommendation were evidence-based, although the strength of some recommendations was limited by a reliance of studies of medium to low quality. We discuss next steps in the refinement and validation of an evidence-based guideline for stopping clozapine and identify key outstanding questions.

Clozapine resistant schizophrenia: Newer avenues of management

About 40%-70% of the patients with treatment-resistant schizophrenia have a poor response to adequate treatment with clozapine. The impact of clozapine-resistant schizophrenia (CRS) is even greater than that of treatment resistance in terms of severe and persistent symptoms, relapses and hospitalizations, poorer quality of life, and healthcare costs. Such serious consequences often compel clinicians to try different augmentation strategies to enhance the inadequate clozapine response in CRS. Unfortunately, a large body of evidence has shown that antipsychotics, antidepressants, mood stabilizers, electroconvulsive therapy, and cognitive-behavioural therapy are mostly ineffective in augmenting clozapine response. When beneficial effects of augmentation have been found, they are usually small and of doubtful clinical significance or based on low-quality evidence. Therefore, newer treatment approaches that go beyond the evidence are needed. The options proposed include developing a clinical consensus about the augmentation strategies that are most likely to be effective and using them sequentially in patients with CRS. Secondly, newer approaches such as augmentation with long-acting antipsychotic injections or multi-component psychosocial interventions could be considered. Lastly, perhaps the most effective way to deal with CRS would be to optimize clozapine treatment, which might prevent clozapine resistance from developing. Personalized dosing, adequate treatment durations, management of side effects and non-adherence, collaboration with patients and caregivers, and addressing clinician barriers to clozapine use are the principal ways of ensuring optimal clozapine treatment. At present, these three options could the best way to manage CRS until research provides more firm directions about the effective options for augmenting clozapine response.

Epigenetic mechanisms in schizophrenia and other psychotic disorders: a systematic review of empirical human findings

Schizophrenia and other psychotic disorders are highly debilitating psychiatric conditions that lack a clear etiology and exhibit polygenic inheritance underlain by pleiotropic genes. The prevailing explanation points to the interplay between predisposing genes and environmental exposure. Accumulated evidence suggests that epigenetic regulation of the genome may mediate dynamic gene-environment interactions at the molecular level by modulating the expression of psychiatric phenotypes through transcription factors. This systematic review summarizes the current knowledge linking schizophrenia and other psychotic disorders to epigenetics, based on PubMed and Web of Science database searches conducted according to the PRISMA guidelines. Three groups of mechanisms in case-control studies  of human tissue (i.e., postmortem brain and bio-fluids) were considered: DNA methylation, histone modifications, and non-coding miRNAs. From the initial pool of 3,204 records, 152 studies met our inclusion criteria (11,815/11,528, 233/219, and 2,091/1,827 cases/controls for each group, respectively). Many of the findings revealed associations with epigenetic modulations of genes regulating neurotransmission, neurodevelopment, and immune function, as well as differential miRNA expression (e.g., upregulated miR-34a, miR-7, and miR-181b). Overall, actual evidence moderately supports an association between epigenetics and schizophrenia and other psychotic disorders. However, heterogeneous results and cross-tissue extrapolations call for future work. Integrating epigenetics into systems biology may critically enhance research on psychosis and thus our understanding of the disorder. This may have implications for psychiatry in risk stratification, early recognition, diagnostics, precision medicine, and other interventional approaches targeting epigenetic fingerprints.

Educational needs and psychoeducation interventions in clozapine users: a narrative review

OBJECTIVE

Increasing users' knowledge about the expected benefits and risks of clozapine may contribute to the initiation and maintenance of clozapine in persons with treatment-resistant schizophrenia (TRS). The objective was to identify the educational needs of clozapine users and the interventions aimed at addressing these needs.

METHOD

We systematically searched multiple electronic databases for articles: (i) exploring educational needs of clozapine users and of their relatives; and (ii) reporting educational interventions aimed at addressing these needs. Data were synthesized narratively.

RESULTS

A total of 30 articles published from 1990 to 2019 in 8 countries fulfilled our inclusion criteria. As most studies on educational needs (n = 18) were carried out in persons already taking clozapine, educational needs of TRS patients who were candidates for clozapine treatment are not well documented. Users' level of knowledge about clozapine was often poor, especially about adverse effects or interactions with other substances, with a poor retention of information delivered at treatment initiation. Among 12 studies reporting educational interventions in clozapine users, five provided quantitative outcomes. Their findings suggest that structured educational programmes may contribute to promote clozapine initiation and to improve users' knowledge about this drug.

CONCLUSION

The literature is sparse on structured educational interventions about clozapine, and only one randomized controlled trial was identified. A promising strategy emerging from this review may be staging educational interventions according to the evolving needs of persons with TRS before clozapine use, at initiation and during maintenance treatment.

Clinical determinants of fever in clozapine users and implications for treatment management: A narrative review

OBJECTIVES

To identify the clinical determinants of fever in clozapine users and their impact on management of clozapine treatment.

METHODS

Articles published in English or French identified with a MEDLINE, Web of Sciences, Cochrane Library and PsycINFO search, from inception through February 2019, using the term "clozapine" in combination with "fever" OR "hyperthermia" OR "body temperature" OR "pyrexia" OR "febrile" OR "heat" OR "thermoregulation". Information extracted for each medical condition were frequency, time to onset after initiation of clozapine treatment, characteristics of fever, associated symptoms, laboratory tests used for diagnosis, course, lethality, discontinuation of clozapine. Data were synthesized narratively.

RESULTS

Our search yielded 394 unique hits published from 1993 to 2018. We included 73 articles in the review: two meta-analyses, 14 reviews, six epidemiological studies, 11 clinical studies and 40 case reports. During clozapine initiation, fever is most frequently benign and transient but should be closely monitored as it may be the first stage of potentially life-threatening adverse drug reactions (ADR) (agranulocytosis, neuroleptic malignant syndrome myocarditis, hepatitis, pancreatitis, nephritis, colitis, etc.). Other ADR associated with fever are independent of duration of exposure to clozapine (heat stroke, pneumonia, pulmonary embolism, necrotizing colitis). If fever is due to intercurrent infection, therapeutic drug monitoring is recommended to adjust clozapine daily dosage.

CONCLUSION

Benign causes of fever are much more frequent than life-threatening ADR during clozapine treatment. Discontinuation should not be considered as automatic in the event of fever, especially during the early phase of clozapine initiation.

Reasons for clozapine discontinuation in patients with treatment-resistant schizophrenia

Although clozapine is more effective than other antipsychotics in the treatment of schizophrenia, the rate of its discontinuation is also high. The aim of this retrospective chart-review study was to investigate the causes of clozapine discontinuation in patients with treatment-resistant schizophrenia. This study included a total of 396 patients with schizophrenia, 240 still on clozapine therapy and 156 who discontinued clozapine, and compared their clinical characteristics. Those who discontinued clozapine had a longer history of illness and more hospitalizations before clozapine and tended to be older. Inadequate response was more common among clozapine discontinuers compared to continuers. The most common reason for discontinuation was the side-effects associated with clozapine (49%). Discontinuation from patient decision or by the psychiatrist due to noncompliance was the second (29.7%) and discontinuation due to lack of efficacy was the third most frequent reason (21.3%). The patients who discontinued clozapine because of cardiac side effects were younger, had shorter duration of clozapine use, and had lower maximum clozapine dose compared to the other discontinuers. Our findings point out the importance of enhancing psychiatrists' ability to handle manageable side effects to minimize discontinuations and maximize the benefits of clozapine in patients with treatment-resistant schizophrenia.

Hyoscine for clozapine-induced hypersalivation: a double-blind, randomized, placebo-controlled cross-over trial

Clozapine is the only evidence-based antipsychotic for treatment-resistant schizophrenia. However, it has considerable side effects, limiting its usability and reducing patients' adherence. One of the most common and distressing side effects is hypersalivation, which can be debilitating, stigmatizing and potentially dangerous through its association with aspiration pneumonia. There is a paucity of evidence guiding possible treatment strategies for hypersalivation. This study aims to examine the efficacy of hyoscine (scopolamine) for clozapine-induced hypersalivation. Fourteen inpatients diagnosed with treatment-resistant schizophrenia, treated with clozapine and suffering from hypersalivation were randomized to receive hyoscine 0.3 mg and placebo daily for 4 weeks each in a randomized, double-blind, placebo-controlled cross-over trial. The primary outcome was improvement in the Toronto Nocturnal Hypersalivation Scale. The secondary outcomes were change in the mass of the pillowcase, anxiety, depression and quality of life. Hypersalivation improved significantly with hyoscine over placebo when measured by the Toronto Nocturnal Hypersalivation Scale (odds ratio=0.21, 95% confidence interval: 0.16-0.28, P<0.001). No significant difference was observed in any of the secondary outcomes. This study showed a beneficial effect of hyoscine over placebo for clozapine-induced hypersalivation.

Predicting Unsuccessful Clozapine Treatment After First Use in Adult Patients With Psychotic Disorders

PURPOSE/BACKGROUND

Cessation of clozapine therapy and insufficient response may result in relapse of psychotic symptoms and in clinical admissions. However, discontinuation rates are high. Identifying patients at risk for unsuccessful clozapine use might enable clinicians to direct specific attention to them.

METHODS/PROCEDURES

Routinely collected data from a large insurance company were used to develop a simple prediction model for unsuccessful clozapine treatment in psychiatric patients 1 year after clozapine was first dispensed by a community pharmacy in the Netherlands. Multivariate logistic regression analyses were performed with the Nagelkerke R statistic as a measure of the predictive value of the model.

FINDINGS/RESULTS

A total of 937 patients were dispensed clozapine for the first time by their community pharmacy between January 1, 2011, and December 31, 2015 (index date). Of these, 741 patients had started their clozapine treatment in hospital before the index date (inpatient starters); the remaining 196 patients started clozapine as outpatients on the index date (outpatient starters). In 191 patients (20.4%), clozapine treatment was unsuccessful 1 year after the index date. Unsuccessful treatment was more common among outpatient starters than among inpatient starters (32.1% vs 17.3%). Using backward selection of the variables, a model consisting of 61 variables had the best predictive value overall (Nagelkerke R = 0.301), whereas a model consisting of 52 variables had the best predictive value in outpatient starters (Nagelkerke R = 0.676).

IMPLICATIONS/CONCLUSIONS

The likelihood of unsuccessful clozapine treatment after 1 year was higher among patients who started clozapine as outpatients. Despite the use of a diversity of variables and different statistical approaches, it was not possible to make a simple prediction model for unsuccessful clozapine treatment using relatively easily accessible data.

Treatment resistant schizophrenia - review and a call to action

Recovery rates in schizophrenia remain suboptimal with up to one-third resistant to standard treatments, a population prevalence of 0.2%. Clozapine is the only evidenced-based treatment for treatment resistant schizophrenia (TRS), yet there are significant delays in its use or it may not be trialled, potentially impacting the chance of recovery. Better outcomes with earlier use of clozapine may be possible. There is emerging evidence that early treatment resistance is not uncommon from the earliest stages of psychosis. In this review, we provide an update on TRS, its epidemiology and its management, with a specific focus on the optimal use and timing of clozapine and augmentation strategies for the one-third of patients who do not respond to clozapine.

Clozapine-induced cardiomyopathy and myocarditis monitoring: A systematic review

The use of clozapine requires monitoring the absolute neutrophil count because of the risk of agranulocytosis, but other potentially fatal adverse events associated with clozapine (specifically, myocarditis and cardiomyopathy) do not have mandatory procedures. We performed a systematic review of English-language articles to synthesize an evidence-based approach for myocarditis and cardiomyopathy monitoring. Articles published from January 1988 through February 2017 were identified through a search of Ovid MEDLINE, Ovid Embase, Ovid Cochrane Database of Systematic Reviews, Web of Science, Scopus, and Google Scholar. Selected articles were required to relate to myocarditis or cardiomyopathy in humans from exposure to clozapine. A total of 144 articles were included. Recommendations varied widely. Some authors recommended baseline laboratory monitoring, with or without follow-up testing, for C-reactive protein, creatine kinase MB, and troponin. Electrocardiography was commonly recommended, and echocardiography was less commonly recommended. The expense of monitoring was a consideration. A unanimous recommendation was to stop the use of clozapine and seek a cardiovascular consultation if myocarditis or cardiomyopathy is suspected. Although there is general agreement on which tests to perform for confirming myocarditis and cardiomyopathy, preemptive screening for these clozapine-induced conditions is controversial, and cost and barriers for the use of clozapine are concerns. For asymptomatic patients receiving clozapine, testing could include baseline electrocardiography, echocardiography as part of a cardiac consultation if patients have cardiac disease or risk factors, and monitoring of C-reactive protein and troponin as indicated.

Long-term follow-up of clozapine prescribing

OBJECTIVE

Clozapine is uniquely effective for treatment-resistant schizophrenia, and so treatment continuation is essential. We aimed to identify factors associated with an increased likelihood of clozapine discontinuation in a cohort of patients in South East London.

METHODS

We gathered demographic and treatment information such as duration of illness and antipsychotic treatment history. t-tests, chi-square tests and binary logistic regression were used to compare patients who continued and discontinued clozapine during the study and to identify predictor variables for discontinuation.

RESULTS

Out of the study population of 133 patients, 48 discontinued clozapine at least once during the study period. The majority of these (75%) stopped treatment within the first 4 years of clozapine therapy. Age, ethnicity, diagnosis and antipsychotic treatment history were not predictive of the risk of clozapine discontinuation. However, male patients were more likely to stop taking clozapine (χ² = 6.81, p = 0.009). The odds of discontinuing clozapine were 2.15 times higher for male patients. The most common reason for discontinuation was patient refusal of treatment.

CONCLUSION

We found that patients who discontinue clozapine are more likely to be male, but no other demographic variable was found to predict treatment cessation. Discontinuation usually occurred due to patient refusal of treatment.

Clozapine in Reducing Aggression and Violence in Forensic Populations

Popular media often portray people with a mental illness as being aggressive, violent, and incarcerated as a result of their behavior. Despite exaggeration in the media, risks for some aggressive behaviors are in fact higher in individuals with schizophrenia. This is often the case with influence of comorbid substance use disorders. It is essential that mental health professionals are aware of treatments that may help with attenuating and treating behaviors that contribute to violence, aggression and incarceration. This paper reviews violence and incarceration in individuals with schizophrenia as well as recommendations, guidelines and benefits for the use of clozapine in this population. Clozapine remains one of the most underutilized evidence-based medications available in the psychiatric arena in the United States. It is a viable and recommended option in the forensic population and it may be helpful on the path to recovery as well as bring substantial savings to the criminal justice system.

Natural Medicines for Psychotic Disorders: A Systematic Review

Patients with psychotic disorders regularly use natural medicines, although it is unclear whether these are effective and safe. The aim of this study was to provide an overview of evidence for improved outcomes by natural medicines. A systematic literature search was performed through Medline, PsycINFO, CINAHL, and Cochrane until May 2015. In 110 randomized controlled trials, evidence was found for glycine, sarcosine, N-acetylcysteine, some Chinese and ayurvedic herbs, ginkgo biloba, estradiol, and vitamin B6 to improve psychotic symptoms when added to antipsychotics. Ginkgo biloba and vitamin B6 seemed to reduce tardive dyskinesia and akathisia. Results on other compounds were negative or inconclusive. All natural agents, except reserpine, were well tolerated. Most study samples were small, study periods were generally short, and most results need replication. However, there is some evidence for beneficial effects of certain natural medicines.

Why do indiviuals with schizophrenia drop out of observational clinical trials?

Randomized controlled trials (RCTs) and observational studies frequently differ with regard to study dropouts. The present naturalistic follow-up investigation aimed to shed a light on this issue by evaluating the time to and the reasons for study dropout in patients suffering from schizophrenia who started monotherapy with an oral new-generation antipsychotic. To this end, psychopathological symptoms and safety data were assessed in 194 patients who were followed up to a maximum observation period of twelve months. 9.3% of study participants completed the study. The mean time to study dropout was 2.6 ± 2.7 months with almost two thirds of patients dropping out within three months. 44.3% discontinued medication at the date of study dropout, the remainders dropped out due to withdrawal of written consent, logistic reasons, or nonappearance to the study visit ("loss to follow-up"), which were not necessarily to be equated with cessation of the antipsychotic. These findings indicate that in contrast to RCTs, dropout of observational studies is not necessarily associated with drug discontinuation. Accordingly, systematic differences between trial designs need to be considered when interpreting the results of clinical trials.

Clozapine administration in clinical practice: once-daily versus divided dosing

OBJECTIVE

While it is recommended that clozapine be administered in a divided dosing regimen, it is unclear whether this recommendation is followed in real-world clinical practice. In two large datasets, we examined clozapine dosing frequency and patient characteristics across different dosing regimens.

METHOD

We conducted a cross-sectional survey, collecting data on patients receiving clozapine in August/September 2015 from the Centre for Addiction and Mental Health (CAMH) in Toronto, Canada, and The Zucker Hillside Hospital (ZHH) in New York, United States.

RESULTS

Of 676 and 308 patients included in CAMH and ZHH datasets, clozapine was prescribed once daily in 75.1% and 74.4%, even though doses exceeding 200 mg/day were administered in 88.6% and 84.4% of the respective samples. No significant difference was found in the rates of positive symptom remission between once-daily vs. divided dosing (79.7% vs. 80.5%, P = 1.00). Higher clozapine dose and use of anticholinergic medications were significantly associated with divided dosing in both datasets. Older age or male gender was related to divided dosing in CAMH or ZHH dataset respectively.

CONCLUSION

Despite the product monograph recommendation, clozapine is frequently prescribed once daily in North America. Further studies are needed to compare clinical outcomes between once-daily vs. divided clozapine dosing.

A Guide to the Management of Clozapine-Related Tolerability and Safety Concerns

Clozapine is a highly effective antipsychotic medication, which provides a range of significant benefits for patients with schizophrenia, and is the standard of care for treatment-resistant schizophrenia as well as for reducing the risk of suicidal behaviors in schizophrenia and schizoaffective disorder. However, clozapine is widely underutilized, largely because prescribing clinicians lack experience in prescribing it and managing its adverse events (AEs). Clozapine is associated with 3 uncommon but immediately dangerous AEs, agranulocytosis, myocarditis/cardiomyopathy, and seizures, as well as AEs that may become dangerous if neglected, including weight gain, metabolic syndrome and constipation, and others that are annoying or distressing such as sedation, nighttime enuresis and hypersalivation. Because of the risk of agranulocytosis, clozapine formulations are available only through restricted distribution via a patient registry, with mandatory, systematized monitoring for absolute neutrophil count using a specific algorithm. We identified articles on managing clozapine-associated AEs by searching PubMed using appropriate keywords and search techniques for each topic. A review of the prevalence and clinical characteristics of clozapine-associated AEs shows that these risks can be managed efficiently and effectively. The absolute risks for both agranulocytosis and myocarditis/cardiomyopathy are low, diminish after the first 6 months, and are further reduced with appropriate monitoring. Weight gain/metabolic disorders and constipation, which develop more gradually, can be mitigated with regular monitoring and timely interventions. Sedation, hypersalivation, and enuresis are common but manageable with ameliorative measures and/or medications.

Reasons for discontinuing clozapine: A cohort study of patients commencing treatment

BACKGROUND

Clozapine is uniquely effective in the management of treatment-resistant schizophrenia (TRS). However, a substantial proportion of patients discontinue treatment and this carries a poor prognosis.

METHODS

We investigated the risk factors, reasons and timing of clozapine discontinuation in a two-year retrospective cohort study of 316 patients with TRS receiving their first course of clozapine. Reasons for discontinuation of clozapine and duration of treatment were obtained from case notes and Cox regression was employed to test the association of baseline clinical factors with clozapine discontinuation.

RESULTS

A total of 142 (45%) patients discontinued clozapine within two years. By studying the reasons for discontinuations due to a patient decision, we found that adverse drug reactions (ADRs) accounted for over half of clozapine discontinuations. Sedation was the most common ADR cited as a reason for discontinuation and the risk of discontinuation due to ADRs was highest in the first few months of clozapine treatment. High levels of deprivation in the neighbourhood where the patient lived were associated with increased risk of clozapine discontinuation (HR=2.12, 95% CI 1.30-3.47).

CONCLUSIONS

Living in a deprived neighbourhood was strongly associated with clozapine discontinuation. Clinical management to reduce the burden of ADRs in the first few months of treatment may have a significant impact and help more patients experience the benefits of clozapine treatment.

Pharmacological interventions for clozapine-induced sinus tachycardia

BACKGROUND

Clozapine is an efficacious treatment for treatment-resistant schizophrenia; however its use can be limited by side effect intolerability. Sinus tachycardia is a common adverse event associated with clozapine treatment. Various pharmacological treatments are used to control heart rate increase due to clozapine use and can include a decreased rate of clozapine titration, a switch to a different antipsychotic, or treatment with negative chronotropic drugs.

OBJECTIVES

To assess the clinical effects and efficacy of pharmacological interventions for clozapine-induced sinus tachycardia.To systematically review the adverse events associated with pharmacological interventions for clozapine-induced sinus tachycardia.

SEARCH METHODS

On 23 March 2015, we searched the Cochrane Schizophrenia Group's Study-Based Register of Trials, which is based on regular searches of CINAHL, BIOSIS, AMED, EMBASE, PubMed, MEDLINE, PsycINFO and registries of clinical trials. There are no language, date, document type or publication status limitations for inclusion of records in the register.

SELECTION CRITERIA

Randomised controlled trials comparing pharmacological interventions, at any dose and by any route of administration, for clozapine-induced tachycardia.

DATA COLLECTION AND ANALYSIS

We independently screened and assessed studies for inclusion using pre-specified inclusion criteria.

MAIN RESULTS

The electronic searches located three references. However, we did not identify any studies that met our inclusion criteria.

AUTHORS' CONCLUSIONS

With no studies meeting the inclusion criteria, it is not possible to arrive at definitive conclusions. There are currently insufficient data to confidently inform clinical practice. We cannot, therefore, conclude whether specific interventions, such as beta-blockers, are less effective or more effective than standard courses of alternative treatments for tachycardia. This lack of evidence for the treatment of clozapine-induced tachycardia has implications for research and practice. Well-planned, conducted and reported randomised trials are indicated. One trial is currently underway. Current practice outside of well-designed randomised trials should be clearly justified.

Prevalence and Predictors of Clozapine-Associated Constipation: A Systematic Review and Meta-Analysis

Constipation is a frequently overlooked side effect of clozapine treatment that can prove fatal. We conducted a systematic review and meta-analysis to estimate the prevalence and risk factors for clozapine-associated constipation. Two authors performed a systematic search of major electronic databases from January 1990 to March 2016 for articles reporting the prevalence of constipation in adults treated with clozapine. A random effects meta-analysis was conducted. A total of 32 studies were meta-analyzed, establishing a pooled prevalence of clozapine-associated constipation of 31.2% (95% CI: 25.6-37.4) (n = 2013). People taking clozapine were significantly more likely to be constipated versus other antipsychotics (OR 3.02 (CI: 1.91-4.77), p < 0.001, n = 11 studies). Meta-regression identified two significant study-level factors associated with constipation prevalence: significantly higher (p = 0.02) rates of constipation were observed for those treated in inpatient versus outpatient or mixed settings and for those studies in which constipation was a primary or secondary outcome measure (36.9%) compared to studies in which constipation was not a specified outcome measure (24.8%, p = 0.048). Clozapine-associated constipation is common and approximately three times more likely than with other antipsychotics. Screening and preventative strategies should be established and appropriate symptomatic treatment applied when required.

Geographical disparities in prescription practices of lithium and clozapine: a community-based study

OBJECTIVE

To explore the socioeconomic and health resource characteristics associated with geographical variations of lithium and clozapine dispensing rates in France.

METHOD

The study was performed using reimbursement data from the French Insurance Healthcare system over the period 2006-2013 in a community-based sample of persons aged 16 years and over. An ecological design was used to assess whether lithium and clozapine prescribing rates were associated with socioeconomic and health resource characteristics of the zone of residence (n = 95 French administrative subdivisions).

RESULTS

Large geographical disparities were observed in dispensing rates: lithium dispensing rates by zone of residence ranged from 0 to 6.6 per 1000 (mean 2.4 per 1000) and clozapine dispensing rates ranged from 0 to 4.9 per 1000 (mean 0.8 per 1000). Higher density of GPs and regular communication between mental health services and primary care were independently associated with higher rates of lithium and clozapine dispensing and with a higher proportion of lithium users among mood-stabilizer users.

CONCLUSION

A sufficient density of GPs and an effective communication and collaboration between mental healthcare services and primary care seems to favor greater access to psychotropic drugs with demonstrated efficacy but often viewed as 'risky' to prescribe.

Clozapine-induced myocarditis, a widely overlooked adverse reaction

OBJECTIVE

We review the published cases of clozapine-induced myocarditis and describe reasons for the higher incidence in Australia (>1%) than elsewhere (<0.1%).

METHOD

Medline was searched to September 2014 using 'clozapine' as the sole term.

RESULTS

A total of around 250 cases of clozapine-induced myocarditis have been published. Fever among patients commencing clozapine has been reported internationally, and very few of these cases were investigated for myocarditis. The time to onset of fever is consistent with its being part of a prodrome of undiagnosed myocarditis, and the risk factors are similar to those for myocarditis. In more severe cases, clozapine is discontinued, avoiding fatalities which may occur with myocarditis. Furthermore, cases of sudden death and respiratory illness may well have been undiagnosed myocarditis. The diagnosis of myocarditis is confounded by the non-specific nature of the signs and symptoms, and it depends on appropriate investigations being conducted at the time of myocardial involvement or, for fatal cases, the affected area of the myocardium being sampled for histology.

CONCLUSION

It is likely that the incidence of myocarditis is around 3%. Implementation of monitoring procedures will increase case ascertainment and result in more patients benefiting from this valuable medication.

Medical management of patients on clozapine: A guide for internists

Clozapine was approved by the US Food and Drug Administration in 1989 for the management of treatment-resistant schizophrenia, and has since proven to reduce symptom burden and suicide risk, increase quality of life, and reduce substance use in individuals with psychotic disorders. Nevertheless, clozapine's psychiatric benefits have been matched by its adverse effect profile. Because they are likely to encounter medical complications of clozapine during admissions or consultations for other services, hospitalists are compelled to maintain an appreciation for these iatrogenic conditions. The authors outline common (eg, constipation, sialorrhea, weight gain) and serious (eg, agranulocytosis, seizures, myocarditis) medical complications of clozapine treatment, with internist-targeted recommendations for management, including indications for clozapine discontinuation.

Clozapine use pattern in persons with and without treatment for Parkinson's disease in real-world conditions: a naturalistic study in a community-based sample

OBJECTIVE

To explore the pattern of clozapine use in persons with severe mental illness and in persons with Parkinson's disease and the characteristics associated with early discontinuation in naturalistic conditions.

METHOD

A historical fixed cohort study of persons newly treated with clozapine was performed on a representative community-based sample of persons affiliated to the French health insurance system (n = 611,393). Treatment for Parkinson's disease was used as a proxy for this condition and lack of such treatment as a proxy for severe mental illness (SMI).

RESULTS

The prevalences of antipsychotic and clozapine use were 4.4% and <0.1% respectively. Of the 237 persons with a new outpatient prescription of clozapine, 25% were prescribed an antiparkinsonian treatment. In persons with SMI, the median duration of the index episode of clozapine treatment was 4.9 months (Interquartile range 1.0-20.5). Longer duration was independently associated with coprescription of anxiolytics or antidepressant. Few new additions of antipsychotics were observed during the clozapine episode.

CONCLUSION

Efforts have to be made to optimize clozapine treatment in real-world conditions. Considering the high frequency of persons with Parkinson's disease among clozapine users, further studies have to be performed in this population.

Discontinuation of clozapine: a 15-year naturalistic retrospective study of 320 patients

OBJECTIVE

Clozapine is underutilized in the management of treatment-resistant schizophrenia. To understand contributing factors, we analyzed the frequency and causes of clozapine discontinuations that occurred over a 15-year period in a clinical setting.

METHOD

Data were extracted from computerized records and from mandatory termination reports for discontinuation events 1993-2007. The reasons for termination were analyzed.

RESULTS

Over half of the patients (n = 183/320; 57%) had at least one discontinuation (median time 609 days). The two most common causes for discontinuation were non-adherence (35%) and side-effects (28%). Hematological side-effects accounted for 45% of all side-effect associated discontinuations; most such patients remained eligible for clozapine treatment, and a significant fraction remained on clozapine after rechallenge. Central nervous system side-effects accounted for 35% of side-effect induced discontinuations. General factors significantly associated with discontinuation were African American race, older age at initiation of clozapine and less improvement in psychiatric symptoms.

CONCLUSION

In addition to anticipating and addressing causes of non-adherence, psychiatrists should consider clozapine rechallenge in eligible patients and implement measures to mitigate clozapine-associated sedation, seizures, and other side-effects. Future studies should particularly address why African American and older patients may be more likely to discontinue clozapine.

Polymorphism in alpha 2A adrenergic receptor gene is associated with sialorrhea in schizophrenia patients on clozapine treatment

OBJECTIVE

Clozapine-induced sialorrhea (CIS) is a common, inconvenient and socially stigmatizing adverse effect. The pathophysiology of CIS may be related to the effect of clozapine on the muscarinic and adrenergic receptors as well as the disruption of the circadian rhythms. The aim of this study was to find out if polymorphisms in muscarinic M1 and M3 receptor genes (CHRM1 and CHRM3), adrenoceptor alpha 2A gene (ADRA2A) or clock circadian regulator gene (CLOCK) are associated with CIS.

METHODS

Two hundred and thirty-seven clozapine-treated Finnish schizophrenia patients were genotyped for CHRM1, CHRM3, CLOCK and ADRA2A polymorphisms, and their salivary dysfunction was assessed with two questions. Twenty-six of these patients had previously been on medication to treat CIS. Comparisons of the genotypes between patients with excessive versus non-excessive salivation were analysed. Genotype distributions between patients and control group and haplotypes were also studied.

RESULTS

CHRM1, CHRM3 and CLOCK polymorphisms and haplotypes were not associated with CIS. ADRA2A (rs1800544) genotype was associated with CIS (p = 0.029). In patients with CIS, CC genotype (n = 103) was more common than in G-allele carriers (n = 79) (p = 0.013, OR 2.13, 95% CI: 1.17-3.88). No differences were found in the distributions of genotypes between patients and controls.

CONCLUSIONS

ADRA2A genotype was associated with CIS.

Effectiveness and safety of rapid clozapine titration in schizophrenia

OBJECTIVE

Clinical guidelines recommend slow clozapine dose titration in order to decrease the risk of seizures and hypotension. The recommendation may delay adequate control of severe psychotic symptoms. We evaluated the safety and effectiveness of rapid clozapine titration in patients who had been previously exposed to the drug and in patients who received clozapine for the first time after failing to respond to other antipsychotics.

METHOD

Analysis of hospital course of a consecutive cohort of schizophrenia patients (N = 111) who received 25-100 mg of clozapine as needed every 6 h the first treatment day, followed by upward adjustments of 25-100 mg/day.

RESULTS

Symptom control was obtained with an average dose of 353 ± 174 mg/day after 4.1 ± 3.1 days in the 73 patients previously treated with clozapine. For the 38 patients initially started on other antipsychotics, the average clozapine dose required for symptom control (409 ± 188 mg/day) was reached after 7.1 ± 4.8 days. None of the patients had seizures, severe hypotension or other major adverse reactions.

CONCLUSION

In this naturalistic cohort study rapid clozapine titration appeared safe and effective for the treatment of schizophrenia. The results justify controlled clinical trials of this treatment method.

Ivabradine, a novel treatment for clozapine-induced sinus tachycardia: a case series

OBJECTIVES

Clozapine is the most efficacious treatment for treatment-resistant schizophrenia; however its use can be limited by intolerability. Sinus tachycardia is a common adverse event associated with clozapine use, which may lead to the premature discontinuation of clozapine. Traditionally, β blockers are used to treat clozapine-associated tachycardia, though problems with intolerability and ineffectiveness can limit their utility.

METHODS

In this article, we present two cases of patients with treatment-resistant schizophrenia who developed symptomatic tachycardia associated with clozapine therapy.

RESULTS

We demonstrate that the novel heart rate controlling agent ivabradine can be effectively and safely used to control the heart rate and to allow for continued treatment with clozapine.

CONCLUSION

This is the first report in the literature demonstrating that ivabradine appears to be a well tolerated agent, which should be considered as a symptomatic treatment of clozapine-induced tachycardia if the use of a β blocker fails due to a lack of response or intolerability.

Augmentation of clozapine with another pharmacological agent: treatment for refractory schizophrenia in the 'real world'

OBJECTIVE

Refractory schizophrenia (SZ) affects approximately 30% of people with SZ. Clozapine (CLZ) is the gold standard treatment; however, there are still patients who are non-responsive or partially responsive to treatment. Although a lack of evidence exists in reality, these patients are treated with a combination of agents in addition to CLZ. Therefore, this article reviews the prevalence of the augmentation of CLZ with additional agents.

METHOD

This study was cross-sectional; physicians in a region of Australia in May 2011 were contacted to provide details of their patients on CLZ and any additional agents. The data set consists of 84 patients.

RESULTS

The majority of the patients 84.5% were taking at least one additional agent. Of those taking additional agents, they derived from the following classes' antipsychotics (72%), antidepressants (30%), mood stabilisers (17%), antimetabolic agents (13%), benzodiazepines (7%), anticholinergics (4%) and miscellaneous agents (12.5%).

CONCLUSION

It is apparent that CLZ is routinely augmented with other agents despite the lack of an evidence base. However, concerning was the lack of augmentation with antimetabolic agents despite the paucity of literature reporting the detrimental impact of antipsychotic treatment upon patients metabolic indices. The findings are discussed in the context of the current recommendations and empirical literature.