Revealing the reporting disparity: VigiBase highlights underreporting of clozapine in other Western European countries compared to the UK

BACKGROUND

Pharmacovigilance studies indicate clozapine history is marked by adverse drug reactions (ADRs).

OBJECTIVE

In a 2021 article, the United Kingdom (UK) had >90 % of European clozapine-related fatal outcomes in VigiBase, the World Health Organization's pharmacovigilance database. Two possibly opposing hypotheses could explain this disparity: 1) fewer reported fatal outcomes in other Western European countries mainly reflect underreporting to VigiBase, and 2) the higher number of UK reports reflects higher real relative mortality.

METHODS

VigiBase reports from clozapine's introduction to December 31, 2022, were studied for ADRs and the top 10 causes of fatal outcomes. The UK was compared with 11 other top reporting Western countries (Germany, Denmark, France, Finland, Ireland, Italy, Netherlands, Norway, Spain, Sweden and Switzerland). Nine countries (except Ireland and Switzerland) were compared after controlling for population and clozapine prescriptions.

RESULTS

The UK accounted for 29 % of worldwide clozapine-related fatal outcomes, Germany 2 % and <1 % in each of the other countries. The nonspecific label "death" was the top cause in the world (46 %) and in the UK (33 %). "Pneumonia" was second in the world (8 %), the UK (12 %), Ireland (8 %) and Finland (14 %). Assuming that our corrections for population and clozapine use are correct, other countries underreported only 1-10 % of the UK clozapine fatal outcome number.

CONCLUSIONS

Different Western European countries consistently underreport to VigiBase compared to the UK, but have different reporting/publishing styles for clozapine-related ADRs/fatal outcomes. Three Scandinavian registries suggest lives are saved as clozapine use increases, but this cannot be studied in pharmacovigilance databases.

[Safety aspects during treatment with clozapine: : Adverse effects, titration, and therapeutic drug monitoring - a narrative review]

BACKGROUND

According to current guidelines, clozapine should be used as a third step in treatment resistant schizophrenia (TRS). In everyday clinical practice, however, it is frequently used at a much later stage, which leads to a significant deterioration of prognosis. The first part of this narrative overview focuses on the most frequent side effects of clozapine, on the relevance of slow titration, and on specific aspects of therapeutic drug monitoring (TDM).

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 for Psychiatry, Psychotherapy and Psychosomatics were searched for relevant literature, the last query dating from April 28th, 2023.

RESULTS

Despite its unique efficacy clozapine is underused in clinical practice and prescription varies between and within countries. Next to hematological, metabolic, and vegetative side effects, clozapine induced inflammation manifesting in the form of pneumonia or myocarditis, which is mainly associated with rapid titration, represents a major clinical challenge with CRP monitoring being of particular relevance. In this context, it also has to be noted that sex, smoking behavior, and ethnic origin impact clozapine metabolism, thus requiring personalized dosing.

CONCLUSION

Slow titration when possible, TDM, and CYP diagnostics when appropriate increase patient safety during treatment with clozapine and thus the likelihood of early prescription of this compound in TRS.

What are the barriers and facilitators of clozapine use in early psychosis? A survey of UK early intervention clinicians

Clozapine is the most effective medication for treatment-resistant psychosis, but evidence points to substantial underuse, especially within early intervention psychosis (EIP) services. We explored clinicians' views on perceived barriers and facilitators to offering patients clozapine within EIP services. A cross-sectional survey was distributed electronically to clinicians practising in EIP services across England. A mixed methods approach was used to assess barriers to clozapine, and attitudes and opinions concerning clozapine underutilisation. Based on the barriers identified in the literature, clinicians were asked to rate each one (scale:1-7) based on importance, with a higher score indicating higher importance. Clinicians were also asked open-ended questions on barriers to clozapine and how access can be improved in EIP services. Quantitative data were analysed using descriptive and inferential statistics, and qualitative responses were analysed thematically. One hundred and nineteen EIP clinicians from 35 services in England completed the survey. In total, 37% (n = 45) of clinicians perceived that clozapine was under-prescribed in their EIP service. The most important barrier to utilising clozapine were patient concerns with side effects, followed by monitoring requirements and clinician concerns with side effects. Thematic analysis identified 17 perceived barriers, which were grouped into three major themes: administrative (5 subthemes), clinician-related (6 subthemes), and patient-related (6 subthemes). Perceived facilitators to improving clozapine use were greater training, improved resources, and optimised monitoring. The main barriers to clozapine in EIP services, as identified by clinicians, are patient concerns regarding side effects and monitoring requirements. Identified facilitators for improved clozapine use include clinician training, improved resources, guidelines, and point-of-care testing.

Maintenance Therapy of Psychosis Spectrum Disorders in a Real-World Setting: Antipsychotics Prescription Patterns and Long-Term Benzodiazepine Use

BACKGROUND

Maintenance therapy of patients with primary psychosis spectrum disorders (PSD) in the Western Balkans has received limited interest so far. The present study aimed to investigate long-term prescription patterns among outpatients with PSD.

METHODS

Information about prescription of antipsychotics (AP), benzodiazepines (BZD) and other psychotropic medication over a 6-month period was collected from outpatients (n = 134; ICD-10 diagnosis F20-29) recruited by a larger multi-site study, to find mean daily number of psychotropic drugs, AP prescription patterns (including AP daily dose, route of administration, monotherapy vs. polypharmacy) and BZD utilization (long-term add-on BZD therapy). Additionally, sex-differences in the variables were explored.

RESULTS

Clinically stable outpatients (age 41.7 ± 11.0; male 62.7%; duration of untreated illness 12.7 ± 8.7 years; mean number of lifetime hospitalizations 2.6 ± 0.7) were prescribed 2.8 ± 1.1 psychotropic medications daily. The mean 6-month AP dose was 14.2 ± 7.8 mg olanzapine equivalents. Long-acting injectable AP was prescribed to 25.2% of the patients. Long-term AP monotherapy was found in 52.7% patients and most of them were prescribed second generation AP (65.2%). Long-term AP polypharmacy (42.7%) was more common in males (p = 0.015). The most frequent co-prescription patterns were first generation AP plus clozapine. The highest rate of long-term AP co-prescription was found for BZD (in 42.7% cases, average 6-months daily dose of 2.8 ± 2.7 mg lorazepam equivalents) and anticholinergics (33.6%).

CONCLUSION

Existing appropriately designed interventions aiming to safely switch the inappropriate therapeutic regimens, i.e. very high prevalence of long-term AP polypharmacy and non-rational BZD co-prescription, should be implemented in the region of Western Balkans.

Clozapine for treatment resistance in early psychosis: a survey of UK clinicians' training, knowledge and confidence

BACKGROUND

Clozapine is the only medication licenced for patients with psychosis that is resistant to conventional antipsychotic treatment. However, despite its effectiveness, it remains widely underutilised. One contributory factor for this may be clinicians' lack of confidence around the management of clozapine.

OBJECTIVE

We conducted a survey of clinicians working in Early Intervention in Psychosis (EIP) services to determine their training needs for clozapine management in EIP services.

METHODS

An electronic survey was made available to all clinicians working in EIP services in England. The survey assessed confidence and training needs regarding managing clozapine in patients with treatment-resistant psychosis. Quantitative data were analysed using total mean scores and the Mann-Whitney U test.

RESULTS

In all, 192 (27%) of approximately 700 clinicians from 35 EIP services completed the survey. Approximately half (54%) had not received training on treatment with clozapine. Experience of training was higher in prescribers than non-prescribers, and among medical than non-medical clinicians. Previous training was associated with significantly higher confidence in offering clozapine and managing treatment-resistant psychosis (p < 0.001). Confidence levels with managing treatment-resistant psychosis and clozapine were relatively high (mean = 4 out of 5, SD = 1). Respondents were most confident about monitoring mental health response to treatment (mean = 5, SD = 1). Participants were least confident about how to discontinue clozapine treatment safely (mean = 3, SD = 1).

CONCLUSION

Most clinicians working in EIP have not received training on the use of clozapine. This may account, in part, for the underutilisation of clozapine in EIP services. The provision of training in the identification of treatment-resistant psychosis and the use of clozapine will likely improve the detection and management of treatment resistance in the early phase of psychosis.

A Comprehensive Monitoring of Clozapine and Related Components in Clinical Practices. Saudi Arabian Scenario

OBJECTIVES

Clozapine is considered as effective medication for treatment resistant schizophrenia. Due to its potential severe adverse effects' clozapine is underused in the clinical settings. Information's on clinical use and monitoring of clozapine is lacking in middle east. This research analysis clozapine prescription and monitoring patterns a in a university teaching hospital in Saudi Arabia.

EXPERIMENTAL DESIGN

A retrospective observational study was conducted in the psychiatric department of a university hospital in Saudi Arabia. Patients on treatment with clozapine for minimum one year were reviewed and assessed for clozapine mandatory and non-mandatory requirements and its correlated factors.

OBSERVATION

Majority of patients were male [(n = 36) 63%] and the average age of was 36.8 ± 12.3. TRS schizophrenia[(n = 49),85%] was the common indications. Prior to initiation of clozapine all recommended guidelines was followed for all patients (100%). In addition to the blood monitoring and vitals LFT (80.75%) and weight (87.77%) were frequently measured. Hematological work up performed routinely throughout initial 18 weeks (71.9 %) and every month (59.6%). Weight gain (29.8%) was the most documented adverse effects.

CONCLUSION

The current study explored experiences with clozapine prescribing practices in a university hospital KSA and suggest that clozapine prescription is completely adhered with already existing guidelines in terms of dosing and monitoring. There exist a careful balance of benefit and risk in term of adverse reaction of clozapine in the local population.

Safety of Use of Clozapine in Patients With Schizophrenia With Comorbid Diabetes Mellitus

PURPOSE/BACKGROUND

To evaluate the outcome of diabetes mellitus among patients of schizophrenia who had diabetes mellitus before starting clozapine.

METHODS

Clozapine data were screened to detect the patients who had diabetes mellitus before starting clozapine. Those who had diabetes mellitus before starting clozapine were taken up for the study.

RESULTS

Of the 468 records screened, 28 patients (5.6%) had diabetes mellitus before starting clozapine. Among the 28 patients, 15 (53.6%) were females, and 13 (46.4%) were male. In three-fourths (75%) of the patients, clozapine was started while these patients were admitted to the inpatient unit. Twenty-six patients had type 2 diabetes mellitus and 2 patients had type 1 diabetes mellitus at the time of starting clozapine. Most patients also had deranged blood glucose levels at the time of starting clozapine and required close monitoring of blood glucose levels and also starting/continuation of antidiabetic medications. None of the patients developed diabetic ketoacidosis during the initial part of the treatment. At the mean follow-up duration of 16 months, most patients were on regular follow-up for more than 1 year, and their blood glucose levels were maintained close to the reference range. Majority of these patients showed good response to clozapine.

CONCLUSIONS

The present study suggests that presence of diabetes mellitus should not stop the clinicians to use clozapine among patients with schizophrenia. However, close monitoring of blood glucose levels must be done.

A Rational Use of Clozapine Based on Adverse Drug Reactions, Pharmacokinetics, and Clinical Pharmacopsychology

Using Richardson and Davidson's model and the sciences of pharmacokinetics and clinical pharmacopsychology, this article reviewed the: (1) poor life expectancy associated with treatment-resistant schizophrenia (TRS), which may be improved in patients who adhere to clozapine; (2) findings that clozapine is the best treatment for TRS (according to efficacy, effectiveness and well-being); and (3) potential for clozapine to cause vulnerabilities, including potentially lethal adverse drug reactions such as agranulocytosis, pneumonia, and myocarditis. Rational use requires: (1) modification of the clozapine package insert worldwide to include lower doses for Asians and to avoid the lethality associated with pneumonia, (2) the use of clozapine levels for personalizing dosing, and (3) the use of slow and personalized titration. This may make clozapine as safe as possible and contribute to increased life expectancy and well-being. In the absence of data on COVID-19 in clozapine patients, clozapine possibly impairs immunological mechanisms and may increase pneumonia risk in infected patients. Psychiatrists should call their clozapine patients and families and explain to them that if the patient develops fever or flu-like symptoms, the psychiatrist should be called and should consider halving the clozapine dose. If the patient is hospitalized with pneumonia, the treating physician needs to assess for symptoms of clozapine intoxication since halving the dose may not be enough for all patients; consider decreasing it to one-third or even stopping it. Once the signs of inflammation and fever have disappeared, the clozapine dose can be slowly increased to the prior dosage level.

The impact of delay in clozapine initiation on treatment outcomes in patients with treatment-resistant schizophrenia: A systematic review

Approximately one-third of patients with schizophrenia have treatment-resistant schizophrenia (TR-SCZ), which is a condition characterized by suboptimal response to antipsychotics other than clozapine. Importantly, treatment with clozapine-the only antipsychotic with an indication for TR-SCZ-is often delayed, which could contribute to negative outcomes. Given that the specific impact of delay in clozapine initiation is not well understood, we aimed to conduct a systematic search of the Ovid Medline^® database to identify English language publications exploring the impact of delay in clozapine initiation on treatment outcomes in patients with TR-SCZ. Additionally, clinico-demographic factors associated with clozapine delay were examined. Our search identified four retrospective studies that showed an association between longer delay in clozapine initiation and poorer treatment outcomes, even after including covariates, such as age, sex, and duration of illness. In addition, we found six studies that showed an association between age and clozapine delay, but results with regard to other clinico-demographic variables were inconsistent. Overall, the available literature reveals a possible link between delay in clozapine use and poorer treatment outcomes in patients with TR-SCZ. However, given the relatively small number of studies on this clinically important topic, future research is warranted to draw more definitive conclusions.