Clozapine-treated Patients Have Marked Gastrointestinal Hypomotility, the Probable Basis of Life-threatening Gastrointestinal Complications: A Cross Sectional Study

High Burden of Ileus and Pneumonia in Clozapine-Treated Individuals With Schizophrenia: A Finnish 25-Year Follow-Up Register Study

OBJECTIVE

The authors used longitudinal biobank data with up to 25 years of follow-up on over 2,600 clozapine users to derive reliable estimates of the real-world burden of clozapine adverse drug events (ADEs).

METHODS

A total of 2,659 participants in the FinnGen biobank project had a schizophrenia diagnosis and clozapine purchases with longitudinal electronic health record follow-up for up to 25 years after clozapine initiation. Diseases and health-related events enriched during clozapine use were identified, adjusting for disease severity. The incidence and recurrence of ADEs over years of clozapine use, their effect on clozapine discontinuation and deaths, and their pharmacogenetics were studied.

RESULTS

Median follow-up time after clozapine initiation was 12.7 years. Across 2,157 diseases and health-related events, 27 were enriched during clozapine use, falling into five disease categories: gastrointestinal hypomotility, seizures, pneumonia, other acute respiratory tract infections, and tachycardia, along with a heterogeneous group including neutropenia and type 2 diabetes, among others. Cumulative incidence estimates for ileus (severe gastrointestinal hypomotility) and pneumonia were 5.3% and 29.5%, respectively, 20 years after clozapine initiation. Both events were significantly associated with increased mortality among clozapine users (ileus: odds ratio=4.5; pneumonia: odds ratio=2.8). Decreased genotype-predicted CYP2C19 and CYP1A2 activities were associated with higher pneumonia risk.

CONCLUSIONS

Clozapine-induced ileus and pneumonia were notably more frequent than has previously been reported and were associated with increased mortality. Two CYP genes influenced pneumonia risk. Pneumonia and ileus call for improved utilization of available preventive measures.

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.

Paralytic ileus in a patient on clozapine therapy showing an inverted clozapine/norclozapine ratio after switching valproic acid to carbamazepine: a case report

This case report examines the possible correlation between the clozapine/norclozapine ratio and the occurrence of constipation and paralytic ileus. We present the case of a 42-year-old patient diagnosed with schizoaffective disorder undergoing clozapine therapy. Despite intensive treatment with clozapine, haloperidol, valproic acid and biweekly electroconvulsive therapy sessions for over a year, florid psychotic symptoms and fluctuating mood swings persisted. Therefore, valproic acid was replaced by carbamazepine, a potent inducer of several CYP450-enzymes. To maintain clozapine plasma levels, fluvoxamine, a CYP1A2-inhibitor, was introduced at a dose of 25 mg before this switch. After addition of carbamazepine, there was a significant decline in clozapine levels, necessitating an increase in fluvoxamine dosage to 50 mg. Five weeks later the patient was admitted to a general hospital with a diagnosis of paralytic ileus. Treatment with enemas proved effective. Drug concentration analysis revealed a 2.5-fold increase in norclozapine levels in the weeks preceding hospital admission, resulting in an inverted clozapine/norclozapine ratio. Treatment with clozapine, carbamazepine and fluvoxamine was continued as the patient demonstrated clinical improvement on carbamazepine. Concurrently, an intensive laxative regimen was initiated. Two weeks later, the patient was readmitted to the general hospital due to suspected paralytic ileus and faecal vomiting, once again displaying an inverted clozapine/norclozapine ratio. We discuss potential mechanisms contributing to the occurrence of the paralytic ileus in this patient, including the antagonism of muscarinic M3 receptors by both clozapine and norclozapine, as well as the agonism of delta-opioid receptors by norclozapine. This case highlights the potential significance of both the clozapine/norclozapine ratio and absolute norclozapine levels as risk factors for constipation and paralytic ileus in patients on clozapine therapy.

Clozapine Efficacy and Adverse Drug Reactions Among a Nationwide Study of 1021 Australians Prescribed Clozapine: The ClozaGene Study

BACKGROUND AND HYPOTHESIS

The ClozaGene Study is a nationwide cohort of adults who have been treated with clozapine. While clozapine is indicated in the management of treatment-resistant schizophrenia, it is associated with a considerable adverse drug reaction (ADR) burden, and not all patients achieve adequate symptomatic response. The current study focuses on self-reported experiences of clozapine use and response, clozapine-associated ADRs, and mental health comorbidity.

STUDY DESIGN

A total of 1021 participants (41.0% female; aged 46.2 ± 10.6 years [range 18-66]) were recruited via a mail-out based on prescriptions for clozapine. Participants completed a self-report questionnaire.

STUDY RESULTS

Most participants (90.1%, n = 912) were living with schizophrenia while 41.5% reported a lifetime diagnosis of depression, 15.6% bipolar disorder, and 8.1% schizoaffective disorder. Clozapine was currently prescribed to 944 (92.5%) participants and 37.8% of these participants self-reported currently taking additional antipsychotic medication. Nearly 3 quarters of participants living with schizophrenia reported that clozapine helped control their schizophrenia symptoms moderately to very well. The most commonly reported ADRs were sialorrhea (80.3%), weight gain (71.0%), constipation (56.9%), and sedation (52.8%). The prevalence of clozapine cessation due to clozapine-induced myocarditis and neutropenia was 1% and 0.4%, respectively.

CONCLUSIONS

Our findings highlight the high rate of psychotic and metabolic symptoms and ADRs among adults prescribed clozapine in the general Australian population. Future genomic analyses will focus on identifying genetic variants influencing clozapine treatment response and side effects.

Clozapine-Related Functional Bowel Obstruction: A Rare Adverse Effect Unmasking Quetiapine and Benztropine Interaction Raising Need for Bowel Surveillance

Randomized controlled trials demonstrate a significant decline in hospital admissions and length of stay following the initiation of clozapine in individuals with bipolar disorder and schizophrenia, along with an increase in quality-adjusted life years. The morbidity and mortality associated with clozapine-induced gastrointestinal hypomotility (CIGH) is greater than agranulocytosis. Despite this, we only have clozapine risk evaluation and mitigation strategies by the US Food and Drug Administration for white cell count monitoring, but none exists for CIGH. Our case highlights CIGH due to multiple factors and recommendations to prevent it and enhance clozapine compliance by conducting a thorough literature review.

Impact of COVID-19 quarantines on clozapine-induced constipation: Experience of utilizing a clozapine-induced constipation protocol at a state forensic psychiatric facility

Objective

Since 2017, Fulton State Hospital (FSH) has implemented a clozapine-induced constipation protocol. In March 2020, FSH initiated unit quarantines to minimize the spread of coronavirus disease (COVID-19). The objective of this study was to evaluate the impact of these quarantines on medical referrals for constipation, the Bristol Stool Chart ratings, utilization of as-needed (PRN) laxatives, and adherence rates with scheduled constipation medication regimens.

Methods

Patients on the clozapine-induced constipation protocol from May 1, 2019 to December 31, 2020, were included, with 10-month pre- and mid-quarantine implementation. Data collected included patient demographics, primary psychiatric diagnosis, and outcome variables. Descriptive statistics and paired t-tests were performed.

Results

A total of 31 patients were included. Most were male (93.5%), with a median age of 40 years. The most common primary diagnosis was schizophrenia. Compared with the pre-quarantine implementation period, there were fewer medical referral contacts per person, less use of PRN laxatives, and slightly lower adherence rates to scheduled constipation medication regimens during the mid-quarantine implementation period.

Conclusion

Compared with the pre-quarantine implementation period, there were fewer medical referrals per person during the mid-quarantine implementation period.

A quality improvement program for managing clozapine-induced constipation in a long-term structured residential setting for persons with serious mental illness

OBJECTIVES

The goal of this quality improvement project (QIP) was to increase awareness of the serious medical consequences of clozapine-associated constipation to front line nursing staff and patients with schizophrenia.

METHODS

The QIP was developed iteratively by psychiatric nurses, psychiatrists and pharmacists with input from patients. The processes involved a literature review, development of educational materials for staff and patients, and the creation of a daily bowel movements log (BML). Implementation involved review of the BML at treatment team meetings, and deployment of pharmacological and non-pharmacological interventions to resolve constipation and increase awareness and knowledge of this clinical concern.

OUTCOMES

The initial pilot screened for symptoms of constipation in patients receiving clozapine and non-clozapine antipsychotic agents and intervening as necessary during multidisciplinary team meetings. Patients benefited from relief of constipation and improved bowel habits. Staff benefited from improved knowledge and making requisite changes in workflow and practice. Feedback allowed refinements to be made to the educational materials for patients and staff. Since full implementation, bowel habits are routinely monitored, and interventions are reviewed for effectiveness. Staff satisfaction with this QIP is reflected in answers to a structured questionnaire and in patient reports (n = 50).

CONCLUSIONS

Clozapine, the only approved and efficacious medication for treatment-resistant schizophrenia is significantly underutilized. Medically consequential constipation can be a serious barrier to retention of patients benefiting from clozapine. Increased awareness and use of educational materials for patients and staff, routine monitoring of bowel habits combined with pharmacological and non-pharmacological interventions can successfully address this clinical problem.

Clozapine-Induced Refractory Colonic Pseudo-Obstruction

The management of treatment-resistant schizophrenia (TRS) is challenging as the medications involved, often atypical antipsychotics, have a host of associated adverse effects. While complications such as agranulocytosis are well established and necessitate close hematological monitoring, the gastrointestinal effects of particular atypical antipsychotics, such as clozapine, are recognized to a lesser extent. The following case of TRS leading to chronic treatment-resistant pseudo-obstruction, eventually requiring total colectomy, highlights the considerable sequelae of clozapine on the gastrointestinal tract. Beyond the effects of severe constipation, the possible implications of ischemic colitis, stercoral perforation, and intraabdominal sepsis warrant a degree of caution when prescribing such medication. This study sheds light on the importance of monitoring bowel motility when administering antipsychotics, particularly clozapine, to avoid these deleterious consequences.

Comprehensive dissection of prevalence rates, sex differences, and blood level-dependencies of clozapine-associated adverse drug reactions

Clozapine is often underused due to concerns about adverse drug reactions (ADRs) but studies into their prevalences are inconclusive. We therefore comprehensively examined prevalences of clozapine-associated ADRs in individuals with schizophrenia and demographic and clinical factors associated with their occurrence. Data from a multi-center study (n = 698 participants) were collected. The mean number of ADRs during clozapine treatment was 4.8, with 2.4 % of participants reporting no ADRs. The most common ADRs were hypersalivation (74.6 %), weight gain (69.3 %), and increased sleep necessity (65.9 %), all of which were more common in younger participants. Participants with lower BMI prior to treatment were more likely to experience significant weight gain (>10 %). Constipation occurred more frequently with higher clozapine blood levels and doses. There were no differences in ADR prevalence rates between participants receiving clozapine monotherapy and polytherapy. These findings emphasize the high prevalence of clozapine-associated ADRs and highlight several demographic and clinical factors contributing to their occurrence. By understanding these factors, clinicians can better anticipate and manage clozapine-associated ADRs, leading to improved treatment outcomes and patient well-being.

A case of comorbidity of schizophrenic catatonia and chronic intestinal pseudo-obstruction Successfully managed with lorazepam

It is challenging to manage schizophrenic catatonia and comorbid chronic intestinal pseudo-obstruction (CIPO). The pathology of catatonia is unclear. There are few reports or research on this issue. In this case, we present a middle-aged woman diagnosed with schizophrenia with catatonic features and comorbid CIPO. In the treatment process, modified electroconvulsive therapy (mECT) improved her stupor and CIPO partially. Lorazepam alleviated her stupor and CIPO completely. It is the first report describing complete remission with lorazepam in patient suffering from comorbid schizophrenic catatonia and CIPO, which may benefit the exploration of pathophysiology and treatment of comorbidity of schizophrenia with catatonia and CIPO.

Lower sertraline plasma concentration in patients co-medicated with clozapine-Implications for pharmacological augmentation strategies in schizophrenia

Augmentation of antipsychotic treatment with antidepressants represents a common and beneficial treatment strategy in patients suffering from schizophrenia. Combining clozapine and the selective serotonin reuptake inhibitor (SSRI) sertraline represents a clinically important strategy in patients with therapy-resistant schizophrenia, but there is limited knowledge about mutual pharmacokinetic interactions. In the present study, we assessed the impact of clozapine on sertraline plasma concentrations. Based on a therapeutic drug monitoring (TDM) database, sertraline plasma concentrations were compared between two groups: patients receiving a combined treatment with sertraline and clozapine (N = 15) and a matched control group receiving sertraline but no clozapine (N = 17). Group differences with respect to raw and dose-adjusted concentrations were assessed using nonparametric tests. Comedication with clozapine was associated with 67% lower median sertraline plasma concentrations (16 vs. 48 ng/mL; p = .022) and 28% lower median dose-adjusted plasma concentrations (C/D; 0.21 vs. 0.29 (ng/mL)/(mg/day); p = .049) as compared to the control group. Scatter plots revealed a complex relationship between the dosage of clozapine and dose-adjusted sertraline concentrations composed of an initial decrease at clozapine doses below 300 mg, an increase between 300 and 600 mg and a final decrease at 800 mg which was best modeled by a third order polynomial term. Cotreatment with clozapine may lead to reduced sertraline plasma concentrations which may be explained by clozapine-induced gastrointestinal hypo-mobility already present at low doses and cytochrome P450 3A4 inducing properties at high clozapine doses. For this drug combination, clinicians should consider TDM to confirm therapeutically effective plasma concentrations of sertraline.

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.

The relation between second-generation antipsychotics and laxative use in elderly patients with schizophrenia

BACKGROUND

We aimed to investigate factors associated with concomitant laxative use among elderly patients with schizophrenia, discharged on second-generation antipsychotics (SGAs), from two large public psychiatric hospitals in Taiwan.

METHODS

Elderly patients with schizophrenia who were discharged between 2006 and 2019 and received SGA monotherapy at discharge were included in the analysis. Multivariate logistic regression was used to identify factors associated with regular laxative use at discharge. The Cochrane-Armitage trend test was used to evaluate whether significant time trends existed for rates of laxative use at discharge.

RESULTS

A total of 2591 elderly patients with schizophrenia were discharged during the study period, and 1727 of 2591 patients who met the inclusion criteria were included for analysis. Of these 1727 patients, 732 (42.4%) also received concomitant laxatives. Female gender, mood stabiliser use and concomitant diabetes mellitus were found to be associated with increased laxative use. Among SGAs, clozapine was associated with the highest rate of laxative use, followed by zotepine, quetiapine, olanzapine and risperidone. Additionally, risperidone, amisulpride, aripiprazole, paliperidone and sulpiride were associated with comparable rates of laxative use. Laxative use rates grew over time from 30.8% in 2006 to 46.6% in 2019 (z = 4.83, P < 0.001).

CONCLUSIONS

Laxative use is common in elderly schizophrenia patients treated with SGAs. In cases of clinically significant constipation, switching to an SGA with a lower risk for constipation, or discontinuing the use of mood stabilisers should be considered, if clinically feasible.

Adverse Drug Reactions in Relation to Clozapine Plasma Levels: A Systematic Review

Clozapine is the gold standard for treatment-resistant schizophrenia. Serious and even life-threatening adverse effects, mostly granulocytopenia, myocarditis, and constipation, are of great clinical concern and constitute a barrier to prescribing clozapine, thus depriving many eligible patients of a lifesaving treatment option. Interestingly, clozapine presents variable pharmacokinetics affected by numerous parameters, leading to significant inter- and intra-individual variation. Therefore, therapeutic drug monitoring of plasma clozapine levels confers a significant benefit in everyday clinical practice by increasing the confidence of the prescribing doctor to the drug and the adherence of the patient to the treatment, mainly by ensuring effective treatment and limited dose-related side effects. In the present systematic review, we aimed at identifying how a full range of adverse effects relates to plasma clozapine levels, using the Jadad grading system for assessing the quality of the available clinical evidence. Our findings indicate that EEG slowing, obsessive-compulsive symptoms, heart rate variability, hyperinsulinemia, metabolic syndrome, and constipation correlate to plasma clozapine levels, whereas QTc, myocarditis, sudden death, leucopenia, neutropenia, sialorrhea, are rather unrelated. Rapid dose escalation at the initiation of treatment might contribute to the emergence of myocarditis, or leucopenia. Strategies for managing adverse effects are different in these conditions and are discussed accordingly.

Drug-induced bowel complications and toxicities: imaging findings and pearls

The use of diverse types of drugs can result in a variety of acute and chronic complications that affect almost any organ. The bowel is one of the organs impacted by the side effects of medications. Imaging frequently plays a crucial role in the detection and characterization of complications occurring in the bowel. They include pseudomembranous colitis or antibiotic-associated colitis; angioedema induced by angiotensin-converting enzyme inhibitors; nonsteroidal anti-inflammatory drug-induced enteropathy; cocaine toxicity; clozapine-induced hypomobility; and bowel toxicity induced by chemotherapeutic agents. It is imperative that radiologists are fully aware of these complications and toxicities as well as the relevant findings. In this way, proper treatment can be implemented immediately. The treatment will involve discontinuation of a drug or a change in regimen.

Clozapine-induced gastrointestinal hypomotility: presenting features and outcomes, UK pharmacovigilance reports, 1992-2017

BACKGROUND

Clozapine-induced gastrointestinal hypomotility (CIGH) affects some 75% of patients treated with clozapine.

AIMS

To document the incidence of potentially harmful CIGH in the UK.

METHOD

We studied spontaneous UK pharmacovigilance reports recorded as clozapine-related gastrointestinal adverse drug reactions, 1992-2017.

RESULTS

There were 527 patients reported with potentially harmful CIGH; 33% (n = 172) died. Deaths averaged 1 per year 1992-1999, 5 per year 2000-2009 and 15 per year 2010-2017. Those who died were older (median 52 years v. 49 years) and had been prescribed clozapine for longer than those who recovered (median 11.3 years v. 4.8 years), but there was no difference in prescribed dose. Within the first 4 years of clozapine treatment, there were 169 reports of CIGH, of which 3% (n = 5) were fatal. At 10-14 years there were 63 reports of CIGH, of which 25% (n = 16) were fatal. Among the deaths, males were younger (median 51, range 22-89 v. median 57, range 24-89 years) with higher clozapine doses (median 450, range 100-900 v. median 300, range 12.5-800 mg/d) than females. In non-fatal CIGH, surgery was the most frequent outcome (n = 92). The procedures included appendectomy, ileostomy, total/partial colectomy, colostomy/stoma and proctosigmoidectomy. Clozapine dosage was reduced in 6 patients, stopped and restarted in 23, 'continued' in 6 and discontinued permanently in at least 76 patients.

CONCLUSIONS

The risk of serious morbidity/mortality from CIGH is substantial. The need to actively monitor bowel function and give laxatives to patients treated with clozapine is clear.

Predictors of laxative use in inpatients with schizophrenia on clozapine

OBJECTIVES

Constipation, a clinical manifestation of gastrointestinal hypomotility, is a common and potentially serious complication of clozapine therapy, requiring laxatives for its prevention and treatment. We explored the predictive factors of the increased laxative use in inpatients receiving a long-term clozapine therapy.

METHODS

In the cross-sectional study of 93 patients in a psychiatric rehabilitation hospital, we examined a four-week prevalence of laxative use and a range of demographic and clinical factors associated with the number of prescribed laxatives.

RESULTS

Seventy-four percent of inpatients with schizophrenia were prescribed laxatives, and they were statistically significant older and taking higher daily doses of clozapine. In generalized Poisson regression analysis, the clozapine dose, age, and comorbid diabetes mellitus and hypothyroidism were independently associated with the number of concurrently used laxatives. No association was found between the laxatives and gender, duration of clozapine treatment, and the number of other medications with a potential to cause constipation.

CONCLUSION

The clozapine dose, age, diabetes mellitus, and hypothyroidism were shown to be the independent predictors of the increased laxative use among inpatients on clozapine and might be associated with the increased risk of clozapine-induced constipation and gastrointestinal hypomotility.

Study on clinical characteristics and related factors of schizophrenic patients with intestinal obstruction

BACKGROUND

There are still few studies on the clinical characteristics and related risk factors of schizophrenia patients with intestinal obstruction. Our aim is to explore the clinical characteristics and related risk factors of schizophrenia patients with intestinal obstruction.

METHODS

This study focused on schizophrenia patients with intestinal obstruction who were hospitalized in the psychiatric department of a hospital in Wuhan from January 2007 to December 2020 as the main research object. We intend to retrospectively analyze the clinical characteristics and related risk factors of schizophrenia patients with intestinal obstruction.

RESULTS

In the 1937 persons with schizophrenia included in this study, 97 patients were complicated with intestinal obstruction, and the incidence was 5.01%.The results of the study showed that patients with age ≥ 60 years old, visiting time ≥ 24 h, hospital stay ≥ 90 days, history of abdominal surgery, course of disease ≥ 5 years, male, and patients with cardiovascular and cerebrovascular diseases are prone to intestinal obstruction; Logistic multiple regression analysis showed that the related risk factors of schizophrenia patients with intestinal obstruction mainly included the patient's age, visiting time, length of hospital stay, history of abdominal surgery, course of disease and gender.

CONCLUSION

The older the age, the longer the hospital stay, the longer the course of the disease, the history of previous surgery, and the male schizophrenia who do not see a doctor within 24 h of the onset, the risk of intestinal obstruction is higher, and it is easy to be misdiagnosed and even life-threatening.

Antipsychotic-Induced Constipation: A Review of the Pathogenesis, Clinical Diagnosis, and Treatment

Antipsychotic-induced gastrointestinal hypomotility and, in particular, its manifestation of constipation are common adverse effects in patients with schizophrenia in clinical practice. Serious complications of antipsychotic-induced constipation include ileus, ischaemic bowel disease, colon perforation, aspiration pneumonia, and bacterial septicaemia, which can be life threatening if left untreated, especially in patients prescribed clozapine. The aim of this paper is to review the latest research on the epidemiology, clinical examination methods, pathophysiology, and treatment options and preventive measures for antipsychotic-induced constipation. While clinicians are normally aware of the overall side effects caused by antipsychotics, constipation is often an under-recognized condition despite its relatively high incidence and its impact on daily living. The incidence of constipation differs among individual antipsychotics, but more than 50% of patients prescribed antipsychotics suffer from constipation. Limited fluid intake, poor dietary habits, and a sedentary lifestyle can also worsen constipation. The mechanisms of antipsychotic-induced constipation may be antagonism of cholinergic, histaminergic, and serotonergic receptors, with both parent drug and metabolite(s) contributing to the effects on gastrointestinal motility. Numerous methods, mainly divided into scale evaluations and objective examinations, are applied to evaluate antipsychotic-induced constipation; however, objective examinations have a greater ability to identify cases of gastrointestinal hypomotility since there is often an under-reporting of symptoms in subjective reporting and scale evaluation due to a higher pain threshold, an inability to express pain sensations, and a lack of symptom awareness in these patients. Antipsychotic drug-induced constipation should be closely monitored in patients receiving these medications, with timely intervention to avoid serious gastrointestinal consequences. There is currently no consensus on the efficacy of laxatives in these patients. Further in-depth studies should explore the underlying mechanisms and devise optimal therapeutic approaches to minimize constipation during antipsychotic treatment.

Microbial Profiles of Patients With Antipsychotic-Related Constipation Treated With Electroacupuncture

Antipsychotic-related constipation (APRC) is one of the most common side effects of taking antipsychotic medication. APRC can seriously impact patient quality of life and is potentially fatal, though the efficacy of current APRC treatments is low for most patients. In this study, we conducted a controlled, pilot randomized, sham-electroacupuncture (SEA) study to assess the efficacy of electroacupuncture (EA) in patients with APRC. We used 16S rRNA gene sequencing to assess the microbial profiles of these patients and analyze how EA treatments affected their bacteria.

Methods: We treated 133 APRC patients with randomly assigned EA treatments or SEA treatments for 4 consecutive weeks, fully evaluating the patients 8 weeks after treatment. The participants, outcome assessors, and statistics were all blind to the EA and SEA treatments. Outcomes assessed included changes in spontaneous bowel movements (SBMs) and the frequency of rescue measures. We detected assessed the microbial diversity of stool specimens both before and after EA treatment using 16S rRNA gene sequencing.

Results: Both EA and SEA treatments reduced the need for constipation rescue measures and did not have serious side effects. EA treatments were better than SEA treatments at increasing SBMs and reducing rescue measures. The diversity of gut microbiota changed after EA treatment. LEfSe analysis indicated changes in the genus (belonging to phylum Proteobacteria) of gut microbiota in patients following EA treatment.

Conclusions: This study found that EA treatment is effective and safe for patients with APRC, and could be associated with changes in their microbial profiles. Further study, with larger sample sizes, is needed to explore the efficacy of EA intervention as a clinical treatment for APRC.

Trial Registration: ChiCTR, ChiCTR-ONC-17010842, http://www.chictr.org.cn/showproj.aspx?proj=18420.

Clozapine and Constipation: A Review of Clinical Considerations and Treatment Options

Psychosis, a break in reality which is manifested as hallucinations, delusions or the disruption in thought process, is the hallmark of schizophrenia. Despite novel pharmacotherapy advancements of antipsychotic medications that have resulted in some patients having the ability to return to social settings and thereby decreasing psychotic symptoms and reducing hospital admissions, there is still a sub-population of patients who remain symptomatic. Treatment-resistant schizophrenia is defined as failure of treatment with at least two different antipsychotics with the proper length of treatment and titration. Clozapine has been heralded as a drug to resolve the puzzle of treatment-resistant schizophrenia. Clozapine has one side effect that is well known, being the development of agranulocytosis. However, there is another side effect that can limit clozapine’s use and can also be life-threatening. Recently, at the end of January 2020, the FDA issued a communications statement which “[strengthened] an existing warning that constipation caused by the schizophrenia medicine clozapine can, uncommonly, progress to serious bowel complications.” After identifying ten cases of constipation from between 2006 to 2016 that progressed to hospitalization, surgery, and even death, the FDA focused their attention on this often overlooked, common side effect, especially when considering the strong anticholinergic effects of clozapine. Although patients are screened by their physicians for agranulocytosis by weekly lab monitoring, constipation is also a complication that needs to be identified and treated. Much like opioid-induced constipation, constipation can also be reduced with the use of laxatives and reduction in the co-prescribing of anticholinergic therapies with clozapine.

Drug-Induced Colitis

Drug-induced colitis encompasses a wide spectrum of colon disorders that can manifest microscopically or macroscopically. Patients present with new-onset colitis or exacerbations of inflammatory bowel diseases; in some cases, colitis resolves with discontinuation of medication. Mucosal injury can be focal or extensive, involving the entire colonic mucosa, and sometimes involves other parts of the gastrointestinal tract. It has been a challenge to determine the proportion of new-onset colitis caused by medication and there are few data on the overall prevalence. We review the drugs that have been linked with development of drug-induced colitis and strategies for physicians who believe their patients have this disorder-usually discontinuation of the drug believed to cause colitis and treatment with steroids or immune-modulating therapies. Physicians must be aware of medications that can cause colitis.

Prevalence and predictors of laxatives use in clozapine-related constipation: an observational study

Clozapine-induced constipation is a frequently overlooked side effect that can prove fatal. This study aimed to investigate the prevalence of constipation and the breakdown of laxatives, and to identify whether use of laxative may be predicted by demographics or baseline metabolic markers in 53 Japanese treatment-resistant schizophrenia inpatients switched to clozapine. Differences of present age, onset age and duration of illness, previous antipsychotic dose using the chlorpromazine equivalent, and 10-items of metabolic markers, including fasting plasma glucose and ratio of triglyceride to high-density lipoprotein cholesterol levels were compared between the laxative and nonlaxative user groups. Sequential changes of defecation scores using Bristol stool form scale, and clozapine dosage at 1, 2 and 3 months were evaluated within each group. Multiple linear stepwise regression analysis was performed to assess the predicting use of laxatives. Half of subjects required treatment with laxative, were significantly older and had longer durations of illness than nonlaxative users. Magnesium oxide and lubiprostone were mainly used singly or in combination. Longer disease duration, and lower levels of fasting blood glucose and insulin resistance were predicting the use of laxatives. Screening and preventive strategies for minimizing clozapine-related constipation should be established in future study.

Mental Health Nurses' Knowledge of Clozapine

Clozapine, sold under the brand name Clozaril, is an antipsychotic medication prescribed since the 1970s as an effective treatment for individuals with treatment resistive schizophrenia. Medical experts have produced extensive literature on the need for close monitoring as this medication can cause life threatening adverse effects. Mental health nurses play a vital role in the management of clozapine, however to date just one study specifically examines psychiatric/mental health nurse's knowledge of this medication. Nurses need to be aware of the adverse effects and be able to provide psychoeducation to help support and inform clients prescribed this medication. This study used a survey questionnaire. A clozapine knowledge questionnaire with 18 questions was developed by De Hert et al. to explore psychiatric/mental health nurse's knowledge on the adverse effects of clozapine. We distributed a shortened version of this knowledge questionnaire (12-multi-choice questions) to 209 mental health nurses working within one Irish Mental Health Service. One hundred and twenty-nine (n = 129) nurses completed the questionnaire with a response rate of 62%. Our results indicated that over 40% of mental nurses had not received sufficient education on clozapine medication during their formal education. We found that just 50% of participants scored over six correct questions out of 12 questions on various areas of knowledge related to clozapine medication. We identified gaps in knowledge on clozapine medication in relation to on myocarditis, epilepsy and metabolic syndrome. We highlighted gaps in mental health nurses' knowledge of clozapine medication that need to be improved in order to help clients. We advocate additional education on clozapine medication at undergraduate education and through educational packages at the service level.

A systematic review and meta-analysis of the association between clozapine and norclozapine serum levels and peripheral adverse drug reactions

RATIONALE

Clozapine is the most effective antipsychotic for treatment-refractory schizophrenia for reducing positive psychotic symptoms. It is associated with a reduction in hospitalisation and overall mortality. In spite of this, clozapine remains underutilised due to its complex adverse drug reaction (ADR) profile.

OBJECTIVE

This systematic review aims to investigate the association of clozapine and norclozapine serum levels, and peripheral ADRs.

METHODS

Studies were searched from four electronic databases (PubMed, EMBASE, PsycINFO and CINAHL) from inception to 12 June 2020. Studies were included if they had adult patients, provided data on steady-state trough clozapine or norclozapine levels and reported on clozapine-associated ADRs. Pregnant women, case reports and series were excluded.

RESULTS

A statistically significant correlation was found for clozapine serum levels and triglycerides (n = 70; r = 0.303, 95% CI 0.0119-0.546, p = 0.042), heart rate (n = 137; r = 0.269, 95% CI 0.0918-0.486, p = 0.035), and overall combined ADRs (n = 160; r = 0.264, 95% CI 0.110-0.405, p = 0.001), but not for absolute neutrophil count (n = 223; r = - 0.164, 95% CI - 0.529-0.253, p = 0.444) or total white cell count (n = 18; r = 0.0176, 95% CI - 0.203-0.237, p = 0.878). Interestingly, norclozapine serum levels were found to be statistically correlated to triglycerides (n = 120; r = 0.211, 95% CI 0.0305-0.378, p = 0.022), total cholesterol (n = 120; r = 0.272, 95% CI 0.0948-0.432, p = 0.003) and weight gain (n = 118; r = 0.208, 95% CI 0.0261-0.377, p = 0.025).

CONCLUSIONS

Heart rate, triglycerides and combined ADRs are significantly correlated with clozapine levels, and triglycerides, total cholesterol and weight gain with norclozapine levels. Future prospective, randomised controlled studies are needed to identify the cause-effect relationship between clozapine levels and peripheral ADRs.

Comprehensive assessment of exposure to clozapine in association with side effects among patients with treatment-resistant schizophrenia: a population pharmacokinetic study

BACKGROUND

There have been scarce data on the distribution of clozapine concentrations in comparison with the recommended range (350-600 ng/ml) or their relationship with side effects among patients with treatment-resistant schizophrenia. Furthermore, no studies have assessed the association between side effects and overall exposure to the drug by calculating the 24-h area-under-curve (AUC).

METHODS

In- and outpatients with schizophrenia or schizoaffective disorder (ICD-10) who were receiving a stable dose of clozapine for ⩾2 weeks were included. Side effects were assessed using the Glasgow antipsychotic side-effects scale for clozapine (GASS-C). Using two collected plasma samples, plasma clozapine and norclozapine concentrations at peak and trough and their 24-h AUC were estimated using population pharmacokinetic models.

RESULTS

A total of 108 patients completed the study (mean ± SD age, 43.0 ± 10.1 years; clozapine dose, 357.5 ± 136.9 mg/day); 33 patients (30.6%) showed estimated trough concentrations of clozapine within the recommended range (350-600 ng/ml) whereas the concentrations were higher and lower than this range among 37 (43.5%) and 28 (25.9%) patients (%), respectively. There were no significant correlations between estimated peak or trough concentrations or 24-h AUC of both clozapine or norclozapine, and GASS-C total or individual scores. No significant differences were found between GASS-C total or individual item scores between the patients with estimated trough concentrations of clozapine of >600 ng/ml and the other subjects.

CONCLUSION

The results suggest that clozapine or norclozapine concentrations are not linked directly to the extent of side effects experienced in clozapine-treated patients with treatment-resistant schizophrenia while the cross-sectional study design limits the interpretation of any causal relationships. These findings indicate that side effects associated with clozapine may occur at any dose or concentration.

Efficacy and Safety of Traditional Chinese Herbal Medicine for Antipsychotic-Related Constipation: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background: Constipation is a common but often ignored side effect of antipsychotic treatment, although it is associated with adverse outcomes. The results of the efficacy and safety of traditional Chinese herbal medicine (TCM) in treating constipation are mixed across studies. This is a systematic review and meta-analysis of randomized controlled trials (RCTs) of the efficacy and safety of TCM compared to Western medicine (WM) in treating antipsychotic-related constipation. Methods: Major international electronic (PubMed, EMBASE, Cochrane Library, and Web of Science) and Chinese (Wanfang, WeiPu VIP, SinoMed, and CNKI) databases were searched from their inception to November 29, 2020. Meta-analysis was performed using the random-effects model. Results: Thirty RCTs with 52 arms covering 2,570 patients in the TCM group and 2,511 patients in the WM group were included. Compared with WM, TCM alone was superior regarding the moderate response rate [risk ratio (RR) = 1.165; 95% confidence interval (CI): 1.096-1.238; P < 0.001], marked response rate (RR = 1.437; 95% CI: 1.267-1.692; P < 0.001), and remission rate (RR = 1.376; 95% CI: 1.180-1.606; P < 0.001) for constipation, while it was significantly associated with lower risk of rash (RR = 0.081; 95% CI: 0.019-0.342; P = 0.001). For the moderate response rate, meta-regression analyses revealed that publication year (β = -0.007, P = 0.0007) and Jadad score (β = 0.067, P < 0.001) significantly moderated the results. For the remission rate, subgroup and meta-regression analyses revealed that the geographical region (P = 0.003), inpatient status (P = 0.035), and trial duration (β = 0.009, P = 0.013) significantly moderated the results. Conclusions: The efficacy of TCM for antipsychotic-related constipation appeared to be greater compared to WM, while certain side effects of TCM, such as rash, were less frequent.

An Open-Label, Head to Head Comparison Study between Prucalopride and Lactulose for Clozapine Induced Constipation in Patients with Treatment Resistant Schizophrenia

Clozapine remains as the gold standard for the management of treatment resistant schizophrenia. Nevertheless, mortality and morbidity associated with Clozapine is partly contributed by its adverse effect of constipation in view of its prominent anticholinergic properties. Despite the evidence that approximately 60% of patients on Clozapine will experience constipation, there is no proper guideline as to the best laxative in the treatment of Clozapine induced constipation. Hence this study was conducted to evaluate the efficacy and safety of Prucalopride and Lactulose in the treatment of Clozapine induced constipation. This was a four week, prospective, open-label head to head comparison study between Prucalopride and Lactulose in the treatment of Clozapine induced constipation. Male and female patients on Clozapine between the age of 18–60 with an established diagnosis of treatment resistant schizophrenia with ≤2 spontaneous complete bowel movement per week were recruited in this study. Eligible patients were assigned into two groups. Patients received Prucalopride 2 mg once daily or Lactulose 10 g once daily for four weeks. Efficacy was analyzed in 58 patients. The proportion of patient with ≥3 spontaneous complete bowel movement (SCBM) was higher in the Prucalopride 2 mg group, reaching significance at Week 4 with p-value of (p = 0.029). The proportion of patient with ≥3 SCBM at Week 1 was 71.4% in the Prucalopride 2 mg group and 60% in the Lactulose 10 g group. The proportion of patient with ≥3 SCBM at Week 4 was 85.7% in the Prucalopride 2 mg group and the proportion remained at 60% in the Lactulose 10 g group. The improvement in the dissatisfaction and treatment satisfaction subscales of the patient assessment of constipation—quality of life (PAC-QOL) were higher in the Prucalopride 2 mg group compared to the Lactulose 10 g group. The common adverse events associated with Prucalopride 2 mg were abdominal pain and loose stools which was transient and subsided within a few days. Over four weeks, in this population of patients with Clozapine induced constipation, Prucalopride 2 mg significantly improved the bowel movement and it was safe.

Reporting of clozapine-induced gastrointestinal hypomotility and factors associated with fatal outcomes in Canada: A pharmacovigilance database study

Clozapine-induced gastrointestinal hypomotility (CIGH) is poorly understood and potentially life-threatening. Herein, we present trends of CIGH annual reporting and explore factors associated with a fatal outcome using 25-years of pharmacovigilance data in Canada. Since 1993, the number of CIGH reports increased 22-fold but the proportion of fatal reports remained relatively stable. Fatal reports of CIGH were associated with older age but not sex, clozapine dose, or clozapine duration. Concomitant use of medications used to treat CIGH (lactulose, docusate sodium) and its associated pain/discomfort (acetaminophen, lorazepam) were more commonly reported in fatal cases. Confirmatory and prospective studies of CIGH are warranted.

Use of Clozapine in the General Hospital

Patients with treatment-resistant schizophrenia receiving clozapine therapy are at risk of potentially serious complications in the general hospital setting, due to the complex pharmacokinetic and pharmacodynamic profile of clozapine. We summarize common clinical challenges that face clinicians who care for clozapine patients in the general hospital, and make recommendations based on the available literature and clinical experience. Early collaborative management between consultation-liaison psychiatry and other clinical teams in the general hospital is paramount to improve clinical outcomes and avoid serious complications in this patient group.

Constipation screening in people taking clozapine: A diagnostic accuracy study

OBJECTIVE

Clozapine is the favoured antipsychotic for treatment-refractory schizophrenia but its safe use requires careful adverse-effect management. Clozapine-induced gastrointestinal hypomotility (CIGH or 'slow-gut') is one of the most common and serious of clozapine's adverse effects. CIGH can lead to paralytic ileus, bowel obstruction, gastrointestinal ischaemia, toxic megacolon, and death. Enquiring about constipation is a simple and commonly used screening method for CIGH but its diagnostic accuracy has not previously been assessed.

METHODS

First, we examined the reliability of asking about constipation compared with asking about Rome constipation criteria in inpatients treated with clozapine (n = 69). Second, we examined the diagnostic accuracy of (1) self-reported constipation and (2) the Rome criteria, compared with the reference standard of gastrointestinal motility studies.

RESULTS

After 30 motility tests, it was clear constipation screening had very poor diagnostic properties in this inpatient group and the study was terminated. Although 73% of participants had objective CIGH on motility testing, only 26% of participants self-reported constipation, with sensitivity of 18% (95% CI: 5-40%). Specificity and positive predictive values were higher (95% CI: 63-100% and 40-100%, respectively). Adding in Rome criteria improved sensitivity to 50% (95% CI: 28.2-71.8%), but half the cases were still missed, making this no more accurate than tossing a coin.

CONCLUSIONS

CIGH is often silent, with self-reported constipation having low sensitivity in its diagnosis. Treating CIGH based on self-reported symptoms questions will miss most cases. However, universal bowel motility studies are impractical. In the interests of patient safety, prophylactic laxatives are suggested for people taking clozapine.

Focussing on the fundaments - assessing and treating Clozapine Induced Gastrointestinal Hypomotility

Background: Clozapine is a second-generation antipsychotic used in treatment-resistant Schizophrenia (TRS). Clozapine Induced Gastrointestinal Hypomotility (CIGH) is the commonest cause of clozapine related death, yet remains under-recognised and under-monitored.Aims and hypothesis: To review the pharmacological management of CIGH. We hypothesised that pharmacological interventions would reduce the incidence of adverse outcomes associated with CIGH.Methods: We retrospectively reviewed consecutive patients treated on clozapine over a one year period on a male acute psychiatric ward. Information on patient demographics, CIGH symptomatology, treatment and outcome were extracted.Results: In total, 14 male patients with a mean age of 43 years (standard deviation 10 years) were included. Of these, 9 patients experienced CIGH during admission, in all cases presenting as constipation. Among patients experiencing CIGH, 8 of 9 (89%) patients received one or more interventions. This was most commonly a stimulant, or osmotic laxative. By discharge, the 8 patients treated were in full remission of CIGH symptoms.Conclusions: A high proportion of patients treated with clozapine experience CIGH, presenting most commonly as constipation. Whilst potentially life-threatening, CIGH can be successfully treated in an acute inpatient setting. Active monitoring of CIGH symptoms in patients initiated, or reinitiated on clozapine is recommended.Key pointsA high proportion of patients treated with Clozapine experience constipation, the cardinal feature of Clozapine Induced Gastrointestinal Hypomotility.Whilst potentially life-threatening, CIGH can be successfully treated in an acute inpatient setting with simple interventions.Active monitoring of CIGH symptoms in patients initiated, or reinitiated on clozapine is recommended.Future research on the potential benefit of prophylactic intervention would be beneficial.

Clozapine-induced stercoral colitis: a surgical perspective

We describe a case of a 46-year-old man with schizophrenia treated with clozapine who presented as an emergency with abdominal pain on the background of a 1 month history of constipation. The initial presenting symptoms were vague and a diagnosis was difficult to establish. Initial CT of the abdomen and pelvis demonstrated only minor abnormalities. He continued to deteriorate until a further CT scan revealed worsening stercoral colitis. He subsequently underwent an emergency total colectomy and ileostomy formation and had a complicated prolonged postoperative recovery. This case highlights the risks that clozapine can have on slowing bowel transit and the dangerous consequences that can occur if not identified early.

Clozapine: why wait to start a laxative?

Clozapine, the antipsychotic of choice for treatment-resistant schizophrenia, has a number of side-effects, some of which are potentially life-threatening. Historically viewed as a relatively minor side-effect, there is increasing awareness of the potentially severe sequalae of constipation secondary to clozapine-induced gastrointestinal hypomotility (CIGH). These include ileus, intestinal obstruction, bowel ischaemia, gastrointestinal necrosis, toxic megacolon and death. CIGH is significantly more common than clozapine-induced blood dyscrasias and has a higher mortality rate. Although strict criteria must be followed to assertively monitor, detect and treat blood dyscrasias in patients taking clozapine, no such framework exists for CIGH. We recommend that prescribing guidelines, regulatory agencies and information from manufacturers should more clearly highlight the risks identified in the literature. Furthermore, we recommend that, in people taking clozapine, constipation should be prevented by prophylactic treatment with laxatives rather than treated only when clinically identified.

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Older patients are significantly more likely to have colon ischaemia-associated conditions that are chronic and complex

BACKGROUND

Colon ischaemia is a common disease which has been associated with various medications and comorbidities.

AIM

To test the hypothesis that there are differences in the frequencies of these associations in older compared with younger patients.

METHODS

A retrospective cohort study was performed of patients hospitalized with colon ischaemia at two major medical centres from 2005-2017. Clinical, colonoscopic and pathologic criteria were used to identify patients admitted with colon ischaemia; patients with other types of colitis were excluded. Demographic and medical data were extracted. Two cohorts were created: patients aged 18-64 years and patients > 65 years. These were compared using SAS 14.3.

RESULTS

A total of 788 patients were included, of which 271 (34.4%) were of ages 18-64 years, and 517 (66.6%) were 65 years old or older. In the older cohort, constipation-inducing medications (83.8% vs 64.1%; P = <0.0001), diuretics (38.1% vs 25.1%; P = <0.001) and nonsteroidal anti-inflammatory drugs (58% vs 41.5%; P = <0.0001) were more common than in the younger cohort. Antipsychotic medication use was more common in the younger cohort (10.4% vs 5.4%; P = 0.01). There was a higher percentage of younger patients with a history of hypercoaguable state (1.9% vs 0.2%; P = 0.03) and dialysis dependence (22.9% vs 8.7%; P = <0.01), while a higher percentage of patients in the older cohort had a history of chronic obstructive pulmonary disease (12% vs 6.3%; P = 0.01) or atrial fibrillation (18.9% vs 10.3%; P = <0.01).

CONCLUSIONS

Our study shows that older patients are more likely to have colon ischaemia-associated conditions that are chronic and complex, while younger patients are more likely to have acute colon ischaemia-associated conditions.

Clozapine-Associated Aspiration During Electroconvulsive Therapy

Clozapine-induced gastric hypomotility (CIGH) is an underreported, underrecognized effect from high-dose clozapine. In this report, we present a patient with treatment refractory schizophrenia receiving high-dose clozapine who aspirated during general anesthesia for electroconvulsive therapy. To our knowledge, this is the first report of aspiration under general anesthesia as a result of CIGH and highlights the potential dangers high-dose clozapine can pose on patients undergoing electroconvulsive therapy with unrecognized CIGH.

Premature Death of a Schizophrenic Patient due to Evacuation after a Nuclear Disaster in Fukushima

Although psychiatric patients are likely to be adversely impacted by disasters, information regarding the processes involved in adverse impacts is limited. In March 2011, Japan experienced an earthquake, tsunami, and the Fukushima Daiichi Nuclear Power Plant accident. In its aftermath, Takano Hospital, 22 km south of the power plant, underwent forced patient evacuation. A 54-year-old Japanese male with schizophrenia, who had been hospitalized in the psychiatric ward for over 20 years, was transferred and experienced a series of hospital relocations. Although his physical status was intact when he left Takano Hospital, his condition gradually worsened, presumably due to incomplete exchange of patient information between institutions and changes in the treatment environment. Having developed ileus a few days prior, he was bedridden when he returned to Takano Hospital in May 2011. Over the course of treatment, he developed aspiration pneumonia and died in August 2011. A review of medical records revealed that all his purgative medicines had been stopped after his evacuation, possibly contributing to the development of ileus. This case highlights the necessity of establishing systems enabling patient information sharing between institutions in disaster settings and the importance of recognizing that long-term evacuation may have fatal impacts for psychiatric patients.

Review article: the pharmacological causes of colon ischaemia

BACKGROUND

Colon ischaemia is the most common ischaemic disorder of the gastrointestinal system, can affect any segment of the colon, and may present with a range of symptoms. Diagnosis can be challenging due to symptom overlap with other conditions, varied aetiology, and often rapid and self-resolving course.

AIM

To review comprehensively the literature regarding the pharmacological aetiologies of colonic ischaemia to enhance the understanding of the various mechanisms of disease, presentations, distribution, and outcomes.

METHODS

A PubMed search for "colon ischaemia" and "ischaemic colitis" alone as well as in combination with various known pharmacologic causes was performed. Only the highest quality and relevant literature was included in this review. The quality of the literature for each association was rated by the authors and a consensus was made when discrepancies were encountered. Only associations that were deemed "moderate" or "strong" were included.

RESULTS

The literature considering pharmacologically associated colonic ischaemia is diverse, lacks codification and is characterised by numerous case reports and case series. Constipation-inducing drugs, digoxin, hormonal therapies, illicit drugs, immunomodulators, laxatives, and NSAIDs were strongly associated with colonic ischaemia. Antimicrobials, appetite suppressants, chemotherapies, decongestants, diuretics, ergot alkaloids, serotonin agents, statins, and vasopressor agents were moderately associated.

CONCLUSIONS

Patients presenting with abdominal pain, diarrhoea, or bloody stool need to be evaluated for the possibility of this condition and treated accordingly. Timely diagnosis is necessary to improve patient outcomes. This review aims to increase awareness among clinicians regarding the presentation of pharmacologically induced colonic ischaemia.

Effects of Clozapine on the Gut: Cross-Sectional Study of Delayed Gastric Emptying and Small and Large Intestinal Dysmotility

BACKGROUND

Gastrointestinal hypomotility in people taking clozapine is common, poorly understood and potentially dangerous. It causes distress and sometimes sudden death, with greater associated morbidity than the better known adverse effect of clozapine, agranulocytosis. Neither the mechanism nor prevalence of clozapine-induced gastrointestinal hypomotility is well understood. Previous studies show clozapine impedes colon transit, likely owing to anticholinergic and anti-serotonergic properties. However, regional gastrointestinal transit times (including gastric and small bowel emptying) have not been quantified.

METHODS

We used wireless motility capsules to measure gastric emptying and small and large bowel transit times in clozapine-treated individuals. We tested 17 clozapine-treated patients without any known gastrointestinal dysfunction, and compared data with matched normative transit times.

RESULTS

Clozapine-treated participants had significant 'slow gut', with dysmotility in at least one region of the gastrointestinal tract evident in 82%, with 59% experiencing multi-regional dysmotility. Delayed gastric emptying was diagnosed in 41%, delayed small bowel transit in 71% and delayed colon transit in 50%. Only 18% of participants had normal studies. Hypomotility was not correlated with ethnicity, sex or duration of treatment. Subjective reporting of constipation had low sensitivity in predicting dysmotility. Delayed gastric emptying had been unrecognised clinically for all participants.

CONCLUSION

Clozapine is associated with significant multi-regional gastrointestinal dysfunction. This is relevant when considering the relationship between clozapine use and conditions such as gastroparesis, choking, aspiration pneumonia, constipation, ileus and intestinal pseudo-obstruction. While the constipating properties of clozapine are now well recognised, this study shows a high degree of vigilance is required for both lower and upper gastrointestinal dysmotility in people taking this antipsychotic.

Constipation, ileus and medication use during clozapine treatment in patients with schizophrenia in Iceland

Purpose of the article: Clozapine is the only evidence based treatment for treatment-resistant schizophrenia. Constipation is a well known side effect of clozapine treatment. The aims of this study are to describe the prevalence of constipation and ileus during clozapine treatment of patients with schizophrenia in Iceland and to assess the concomitant use of medication that can cause constipation, and laxatives used to treat constipation.

MATERIALS AND METHODS

We identified 188 patients treated with clozapine by searching the electronic health records of Landspitali, the National University Hospital, during the study period 1.1.1998 - 21.11.2014. Cases of constipation and ileus were identified using an electronic search with keywords related to ileus in the patients' electronic health records. Detailed medication use was available for 154 patients that used clozapine for at least one year.

RESULTS

Four out of 188 patients were diagnosed with ileus that resulted in admission to hospital. Two of these required a permanent stoma as a consequence of their ileus. Laxatives were prescribed for 24 out of 154 patients (15.4%) while on clozapine. In total 40.9% of the patients either had laxatives prescribed or had constipation documented in the medical records. Apart from clozapine, other medications known to cause constipation were prescribed to 28 out of 154 patients (18.2%).

CONCLUSIONS

Constipation is a common problem during clozapine treatment which can progress to full-blown ileus which can be fatal. Clinicians need to monitor signs of constipation during treatment with clozapine and respond to it with lifestyle advice and laxative treatment.

Potentially fatal outcomes associated with clozapine

Clozapine has been shown to be the most efficacious therapy for treatment resistant schizophrenia, estimated at one third of all schizophrenia cases. There is significant morbidity and mortality associated with clozapine including risk of agranulocytosis, aspiration pneumonia, bowel ischemia, myocarditis, seizures, and weight gain. Here we present a case of a 62-year-old man with chronic paranoid schizophrenia refractory to numerous antipsychotics who was started on clozapine therapy during an acute inpatient psychiatric admission. Within three weeks of starting clozapine, the patient developed flu-like symptoms, pleuritic chest pain, and was sent to a medical hospital for evaluation. After transfer, the patient had a rapidly deteriorating course with newly developed congestive heart failure, acute respiratory failure requiring intubation, and cardiovascular collapse requiring vasopressors. The patient expired within two days of transfer and four days after initial symptoms developed. The underlying etiology in this case is likely clozapine induced myocarditis leading to rapid cardiovascular collapse and death. Mortality with clozapine induced myocarditis has been estimated up to 24%. Given that 90% of clozapine cardiotoxic sequelae are seen in the first month post-initiation, more rigorous post-initiation surveillance is recommended for the first four weeks of clozapine with weekly cardiac enzymes (troponins, creatinine kinase-MB), EKG, and acute inflammatory markers (C-reactive protein, and erythrocyte sedimentation rate).

Genetic Polymorphisms Associated With Constipation and Anticholinergic Symptoms in Patients Receiving Clozapine

BACKGROUND

Clozapine impairs gastrointestinal motility owing to its anticholinergic and antiserotonergic properties. This commonly leads to constipation and potentially to more severe complications such as bowel obstruction and ischemia. The aim of this study was to determine whether genetic variations in the genes encoding muscarinic and serotonergic receptors (CHRM2, CHRM3, HTR2, HTR3, HTR4, and HTR7) explain the variations in incidence of constipation and anticholinergic symptoms during clozapine treatment. Genes associated with opiate-induced constipation were also included in this analysis (TPH1, OPRM1, ABCB1, and COMT).

PROCEDURES

Blood samples from 176 clozapine-treated, Finnish, white patients with schizophrenia were genotyped. Constipation and anticholinergic symptoms were rated using the Liverpool University Neuroleptic Side Effect Rating Scale self-report questionnaire. In total, 192 single-nucleotide polymorphisms (SNPs) were detected and grouped to formulate a weighted genetic-risk score (GRS).

RESULTS

No significant associations between individual SNPs or GRSs and constipation or laxative use were observed. A GRS of 19 SNPs in CHRM2, CHRM3, HTR3C, HTR7, ABCB1, OPRM1, and TPH1 was associated with anticholinergic symptoms in a generalized linear univariate model, with body mass index, clozapine monotherapy, and GRS as explaining variables (permuted P = 0.014). Generalized linear univariate model analysis performed on the opiate-induced constipation-associated SNPs and a single CHRM3 SNP revealed an association between anticholinergic symptoms and a score of 8 SNPs (adjusted P = 0.038, permuted P = 0.002).

CONCLUSIONS

Two GRSs are able to predict the risk of anticholinergic symptoms in patients receiving clozapine and possibly an increased risk of gastrointestinal hypomotility.

Risk of gastrointestinal Hypomotility in schizophrenia and schizoaffective disorder treated with antipsychotics: A retrospective cohort study

OBJECTIVE

The risk of gastrointestinal hypomotility (GIHM) with the use of antipsychotic medications in patients with schizophrenia remains inadequately recognized. The aim of this study was to explore the incidence of GIHM and its risks in patients with schizophrenia treated with antipsychotics.

METHODS

We conducted a retrospective cohort study using the National Health Insurance Research Database. We identified adult (≥ 20years of age) patients with a first-time diagnosis of schizophrenia or schizoaffective disorder in the Registry for Catastrophic Illness Patients during the period from 2001 to 2011. Each subject in the cohort was followed until their corresponding diagnosis of GIHM was made, until the time of death, or to December 31, 2012. The incidence rates of each outcome were calculated. Cox proportional hazards regression with time-dependent covariates for antipsychotics use was employed to evaluate the associations between different types of antipsychotics and the risk of GIHM.

RESULTS

Our study found that the incidence densities of constipation, ileus, and ischemic bowel disease were 42.5, 4.4, and 0.1 per 1000 person-years. In terms of the risk of hypomotility with the use of antipsychotics, clozapine and quetiapine were significant in developing constipation, with a hazard ratio of 2.15 and 1.34, respectively. High-potency first-generation antipsychotics and clozapine were also significant in the occurrence of ileus, with a hazard ratio of 1.30 and 1.95, respectively. Similar associations were found in an anticholinergic agent subgroup analysis.

CONCLUSION

Patients receiving antipsychotics such as high-potency first-generation antipsychotics, clozapine, or quetiapine should undergo proper evaluation and intervention to minimize the disease burden and life-threatening outcomes of treatment.

Safety of antipsychotics for the treatment of schizophrenia: a focus on the adverse effects of clozapine

Clozapine, a dibenzodiazepine developed in 1961, is a multireceptorial atypical antipsychotic approved for the treatment of resistant schizophrenia. Since its introduction, it has remained the drug of choice in treatment-resistant schizophrenia, despite a wide range of adverse effects, as it is a very effective drug in everyday clinical practice. However, clozapine is not considered as a top-of-the-line treatment because it may often be difficult for some patients to tolerate as some adverse effects can be particularly bothersome (i.e. sedation, weight gain, sialorrhea etc.) and it has some other potentially dangerous and life-threatening side effects (i.e. myocarditis, seizures, agranulocytosis or granulocytopenia, gastrointestinal hypomotility etc.). As poor treatment adherence in patients with resistant schizophrenia may increase the risk of a psychotic relapse, which may further lead to impaired social and cognitive functioning, psychiatric hospitalizations and increased treatment costs, clozapine adverse effects are a common reason for discontinuing this medication. Therefore, every effort should be made to monitor and minimize these adverse effects in order to improve their early detection and management. The aim of this paper is to briefly summarize and provide an update on major clozapine adverse effects, especially focusing on those that are severe and potentially life threatening, even if most of the latter are relatively uncommon.