Clozapine and tardive dyskinesia in patients with schizophrenia: A systematic review

Clozapine-Induced Acute Pericarditis and Cardiac Tamponade: Early Recognition Improves Clinical Outcomes

Clozapine is approved for treatment-resistant schizophrenia. Many cardiovascular side effects are associated with clozapine, including QTc prolongation and myocarditis, which is a black box warning. Few cases of pericarditis have been reported in recent literature. We report a case of a 26-year-old male with schizoaffective disorder who presented with sharp chest pain and shortness of breath. The patient was started on clozapine three months prior to his current presentation. The workup revealed a large pericardial effusion with cardiac tamponade physiology and signs consistent with acute pericarditis. He required emergent pericardiocentesis and pericardial drain placement. Symptoms resolved after treatment with ibuprofen and colchicine. This case report highlights the importance of early diagnosis of life-threatening cardiovascular complications associated with clozapine, especially acute pericarditis and cardiac tamponade due to pericardial effusion. We strongly recommend implementing monitoring protocols to prevent this potentially life-threatening adverse effect in patients taking clozapine.

Management of tardive dyskinesia and tardive dystonia with clozapine: A retrospective study

AIM

This retrospective study aimed to evaluate the long-term effectiveness of switching to clozapine in the management of tardive syndromes (TS).

METHODOLOGY

The treatment records of patients who had TS at the time of starting clozapine, were reviewed and demographic and clinical data was extracted on a predesigned performa.

RESULTS

About three-fourth (74.2 %) of the study subjects had tardive dystonias and two-third (69.7 %) had tardive dyskinesia at the time of starting clozapine. About half (48.5 %) of the patients had both tardive dystonia and dyskinesia. A small proportion (13.6 %) also had tardive akathisia at the time of starting clozapine. About three-fourth (72.2 %) of the patients had >50 % reduction, and about two-third (66.6 %) of the patients had >75 % reduction and nearly half (54.5 %) of the patients had complete resolution of dyskinesia at the last follow-up. Similar trends were seen in reduction in dystonia, i.e., >50 % reduction in 74.3 %, >75 % reduction in 62.2 % and complete resolution was seen in 56.1 %.

CONCLUSIONS

The present study suggest that clozapine is useful in the management of drug induced tardive dyskinesia and tardive dystonia.

Pharmacovigilance in Action: Utilizing VigiBase Data to Improve Clozapine Safety

Purpose

Clozapine is an antipsychotic which was approved in 1989 for treatment-resistant schizophrenia in the United States (US). There were few randomized trials before its approval and potentially lethal clozapine adverse drug reactions (ADRs), such as agranulocytosis and myocarditis were identified by pharmacovigilance. VigiBase, the WHO global database, is a cornerstone of international pharmacovigilance efforts for ADR identification during post-marketing surveillance. This systematic review of the literature explores additional contributions to the knowledge of clozapine ADRs from recent VigiBase studies.

Methods

Using the terms "clozapine AND VigiBase" we conducted an article search in PubMed on September 5, 2024. Of the 29 articles, 11 were excluded and 18 described in the Results section.

Results

All clozapine ADRs were described in two VigiBase studies. One on pregnancy indicated no increased risk with clozapine compared with other antipsychotics; the other reported 191,557 clozapine ADRs, including 22,956 fatal outcomes through January 15, 2023, and paid attention to the reporting style of the top 4 reporting countries (the US, the United Kingdom, Canada and Australia). Infections were described in three VigiBase studies where clozapine treatment was associated with infections, respiratory aspiration, and pneumonia. Rapid titration can lead to localized clozapine-induced inflammations including myocarditis, pericarditis or pancreatitis, or generalized inflammations such as drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome. Clozapine-induced inflammation was described in four VigiBase studies, two focused on all ages (myocarditis and DRESS) and two on youth (myocarditis and another on pericarditis and pancreatitis). Other specific ADRs were described in nine VigiBase studies (hematological malignancies, rhabdomyolysis, sialorrhea, seizures, diabetes mellitus, drug-induced parkinsonism, withdrawal symptoms, and suicidal behaviors).

Conclusion

The spectrum of respiratory aspiration - aspiration pneumonia - pneumonia and other infections are significant causes of fatal outcomes in clozapine-treated patients. Clozapine had anti-suicidal effects versus other antipsychotics across all VigiBase labels of suicidal behavior.

Tardive Dyskinesia with Antipsychotic Medication in Children and Adolescents: A Systematic Literature Review

BACKGROUND

Tardive dyskinesia (TD) is a persisting, and potentially irreversible, movement disorder associated with treatment with dopamine receptor antagonists. Few data are available on the risk of TD in children and adolescents treated with antipsychotic medication.

OBJECTIVE

To review the literature on incidence, risk factors, and treatment options for antipsychotic-associated TD in children and adolescents (aged < 18 years).

METHODS

Relevant articles were identified through a systematic search of Embase and Medline performed in January 2024. Methodological quality was assessed using the Newcastle-Ottawa Scale and Joanna Briggs Institute Critical Appraisal tools.

RESULTS

Thirteen studies were identified. The reported TD point prevalence was 5-20%, with higher rates in studies involving typical antipsychotics. Lower estimates (around 1%) emerged from analyses of clinical database data suggesting underdiagnosis in clinical practice. Risk factors included treatment with typical antipsychotics, higher doses, longer duration of exposure, older age, female gender, higher baseline Abnormal Involuntary Movements Scale (AIMS) scores, intellectual impairment, and perinatal complications.

CONCLUSION

Although relatively few cases have been reported in children and adolescents, TD remains a risk in this population. Individuals receiving antipsychotics should be monitored carefully for the emergence of abnormal movements. Other than dose reduction, discontinuation, or switch to a lower-risk antipsychotic, few interventions have demonstrated efficacy. The strongest evidence for pharmacological treatment is for VMAT-2 inhibitors (valbenazine and deutetrabenazine), but these drugs are not licensed for use in children. To reduce risk, antipsychotics should be prescribed only if necessary, at the minimum effective dose and for the minimum necessary duration.

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.

A review on side effect management of second-generation antipsychotics to treat schizophrenia: a drug safety perspective

INTRODUCTION

Effective side effects management present a challenge in antipsychotic treatment with second-generation antipsychotics (SGAs). In recent years, most of the commonly used SGAs, except for clozapine, have been shown to differ only slightly in their effectiveness, but considerably regarding perceived side effects, safety profiles, and compatibility to preexisting medical conditions.

AREAS COVERED

The current state of available evidence on side-effect management in SGA treatment of patients with schizophrenia spectrum disorders (SSD) is reviewed. In addition, current guideline recommendations are summarized, highlighting evidence gaps.

EXPERT OPINION

SGA safety and side effects needs to be considered in treatment planning. Shared decision-making assistants (SDMA) can support patients, practitioners and relatives to orient their decisions toward avoiding side effects relevant to patients' adherence. Alongside general measures like psychosocial and psychotherapeutic care, switching to better tolerated SGAs can be considered a relatively safe strategy. By contrast, novel meta-analytical evidence emphasizes that dose reduction of SGAs can statistically increase the risk of relapse and other unfavorable outcomes. Further, depending on the type and severity of SGA-related side effects, specific treatments can be used to alleviate induced side effects (e.g. add-on metformin to reduce weight-gain). Finally, discontinuation should be reserved for acute emergencies.

Rethinking Clozapine: Lights and Shadows of a Revolutionary Drug

The current literature globally highlights the efficacy of Clozapine in several psychiatric disorders all over the world, with an FDA indication for reducing the risk of repeated suicidal behavior in patients with schizophrenia or schizoaffective disorder. A growing field of research is also stressing a possible broader beneficial effect of Clozapine in promoting neuroprotection and neurotrophism. However, this drug is linked to several life-threatening side effects, such as agranulocytosis, myocarditis and seizures, that limit its use in daily clinical practice. For this work, a search was performed on PubMed using the terms "Clozapine indications", "Clozapine adverse effects", "Clozapine regenerative effects", and "Clozapine neuroplasticity" with the aim of reviewing the scientific literature on Clozapine's treatment indications, adverse effects and potential regenerative role. The results confirmed the efficacy of clozapine in clinical practice, although limited by its adverse effects. It appears crucial to raise awareness among clinicians about the potential benefits of using Clozapine, as well educating medical personnel about its risks and the early identification of possible adverse effects and their management.

Multiple therapies relieve long-term tardive dyskinesia in a patient with chronic schizophrenia: A case report

BACKGROUND

Tardive dyskinesia (TD) is a serious and disabling movement disorder; it impairs social function and quality of life and increases the mortality rate. TD is usually induced by the use of antipsychotic drugs; however, the underlying mechanism remains unclear. Pharmacotherapy of TD includes cholinergic drugs, benzodiazepines, ginkgo biloba extract (GBE), antioxidants, amantadine, propanolol, botulinum toxin, valbenazine, and deutetrabenazine, whereas the non-pharmacotherapy approach includes modified electroconvulsive therapy (MECT) and deep brain stimulation. We successfully treated a chronic schizophrenia patient with comorbid long-term severe TD using deutetrabenazine, clozapine, and MECT.

CASE SUMMARY

A 69-year-old woman who was diagnosed as having schizophrenia 16 years ago developed severe TD after 6-mo prescription of risperidone oral solution. Her TD symptoms did not resolve despite various treatments, such as GBE, vitamin E, trihexyphenidyl, promethazine, benzodiazepines, and switching to quetiapine and olanzapine. After admission, she was given deutetrabenazine 6 mg bid. Her buccal tremor was slightly resolved 3 d later; however, her tongue remained protruded and could not be retracted. Quetiapine was switched to clozapine on day 4, and the buccal tremor remarkably resolved, and the tongue could be retracted into the mouth from day 6 onward. After three sessions of MECT, the buccal tremor resolved further. Since then, she has been able to take a semifluid diet, and her quality of life improved remarkably during 6 mo of follow-up.

CONCLUSION

TD is a serious condition which could be caused by antipsychotic medications; however, the best strategy against TD is prevention and monitoring during using antipsychotics. For patients with TD caused by antipsychotic medication use, multiple measures should be considered like switching to clozapine, adjunction with deutetrabenazine, or even MECT.

Improvement of Tardive Dyskinesias with Olanzapine

Tardive dyskinesia (TD) is characterized by abnormal and involuntary movements that generally occur after prolonged exposure to neuroleptic medications. In this article, we present the case of a 29-year-old man with schizophrenia who developed TD following treatment with haloperidol. Despite various attempts with benzodiazepines, amantadine, and anticholinergics, the dyskinesias persisted. However, after 2 years of treatment with olanzapine alone, a progressive improvement occurred, leading to the complete disappearance of the dyskinesias. We also provide a brief review of reported cases of antipsychotic-induced TD that has improved with olanzapine.

Treatment of severe tardive dyskinesia with concurrent administration of olanzapine, clonazepam, baclofen, and gabapentin: a case report

BACKGROUND

Long-term use of antipsychotics or other dopamine antagonists can result in the extrapyramidal side effect of tardive dyskinesia (TD).Case presentation: An 18-year-old female patient experienced abnormal speech and behavior and because of an equivocal diagnosis, she was given daily doses of 300 mg of quetiapine and 60 mg of ziprasidone. She had used these medications for 2 years before the appearance of involuntary abnormal movements. These movements, which were classified as TD, steadily worsened and markedly interfered with her daily life. Following a trial-and-error course of therapy with vitamin E, vitamin B6, amantadine, valproic acid sodium, lorazepam, and diazepam, the drugs were gradually reduced and stopped, yet the aberrant movements persisted. Finally, the patient was given olanzapine, clonazepam, baclofen, and gabapentin. The Abnormal Involuntary Movement Scale was used to assess changes in the patient's condition. Her TD was efficiently managed through co-administration of olanzapine, clonazepam, baclofen, and gabapentin.

CONCLUSIONS

The possibility of TD inducing by antipsychotic use is a clinical concern, even though atypical antipsychotics decrease the incidence of extrapyramidal side effects, and it cannot be entirely excluded. This report provides useful insights into the management of TD and will help clinicians manage similar cases.

A new era in the diagnosis and treatment of tardive dyskinesia

Tardive dyskinesia (TD) is a heterogeneous, hyperkinetic movement disorder induced by dopamine-receptor blocking agents that presents a unique challenge in the treatment of psychosis. Although acceptance of TD as a serious consequence of antipsychotic treatment was resisted initially, subsequent research by many investigators in psychopharmacology contributed to a rich store of knowledge on many aspects of the disorder. While basic neuroscience investigations continue to deepen our understanding of underlying motor circuitry, past trials of potential treatments of TD focusing on a range of theoretical targets were often inconclusive. Development of newer antipsychotics promised to reduce the risk of TD compared to older drugs, but their improved tolerability unexpectedly enabled an expanding market that paradoxically both increased the absolute number of patients at risk and diminished attention to TD which was relegated to legacy status. Fortunately, development and approval of novel vesicular monoamine transporter inhibitors offered evidence-based symptomatic treatment of TD for the first time and rekindled interest in the disorder. Despite recent progress, many questions remain for future research including the mechanisms underlying TD, genetic predisposition, phenomenological diversity, whether new cases are reversible, how to implement best practices to prevent and treat TD, and whether the development of novel antipsychotics free of the risk of TD is attainable. We owe our patients the aspirational goal of striving for zero prevalence of persistent symptoms of TD in anyone treated for psychosis.

Unique effect of clozapine on adenosine A2A-dopamine D2 receptor heteromerization

The striatal dopamine D2 receptor (D2R) is generally accepted to be involved in positive symptoms of schizophrenia and is a main target for clinically used antipsychotics. D2R are highly expressed in the striatum, where they form heteromers with the adenosine A2A receptor (A2AR). Changes in the density of A2AR-D2R heteromers have been reported in postmortem tissue from patients with schizophrenia, but the degree to which A2R are involved in schizophrenia and the effect of antipsychotic drugs is unknown. Here, we examine the effect of exposure to three prototypical antipsychotic drugs on A2AR-D2R heteromerization in mammalian cells using a NanoBiT assay. After 16 h of exposure, a significant increase in the density of A2AR-D2R heteromers was found with haloperidol and aripiprazole, but not with clozapine. On the other hand, clozapine, but not haloperidol or aripiprazole, was associated with a significant decrease in A2AR-D2R heteromerization after 2 h of treatment. Computational binding models of these compounds revealed distinctive molecular signatures that explain their different influence on heteromerization. The bulky tricyclic moiety of clozapine displaces TM 5 of D2R, inducing a clash with A2AR, while the extended binding mode of haloperidol and aripiprazole stabilizes a specific conformation of the second extracellular loop of D2R that enhances the interaction with A2AR. It is proposed that an increase in A2AR-D2R heteromerization is involved in the extrapyramidal side effects (EPS) of antipsychotics and that the specific clozapine-mediated destabilization of A2AR-D2R heteromerization can explain its low EPS liability.

Pharmacokinetics, safety and tolerability of valbenazine in Korean CYP2D6 normal and intermediate metabolizers

Valbenazine is a selective vesicular monoamine transporter 2 (VMAT2) inhibitor approved for tardive dyskinesia treatment by the US Food and Drug Administration; its major active metabolite (NBI-98782) is a 45-fold more potent inhibitor of VMAT2 than the parent drug. This study aimed to evaluate the pharmacokinetics (PKs), safety, and tolerability and the effect of cytochrome P450 2D6 (CYP2D6) genotypes to the PKs after the administration of valbenazine in Korean participants. A randomized, double-blind, placebo-controlled, single- and multiple-dose study was conducted in healthy Korean male participants. The single-dose study was conducted for both 40 and 80 mg valbenazine and the multiple dose study was conducted for 40 mg. After a 1-week washout, the 40 mg dose group participants received valbenazine 40 mg or placebo once daily for 8 days. Serial blood samples were collected up to 96 h postdose for PK analysis. The CYP2D6 genotypes of the participants were retrospectively analyzed. A total of 50 participants were randomized, and 43 and 20 participants completed the single- and multiple-dose phases of the study, respectively. After single doses, the PK characteristics of valbenazine and its metabolites were similar between the 40 and 80 mg dose groups. After multiple doses, the mean accumulation ratios of valbenazine and NBI-98782 were ~1.6 and 2.4, respectively. Plasma concentrations of valbenazine and NBI-98782 were similar between CYP2D6 normal and intermediate metabolizers. Valbenazine was well-tolerated in healthy Koreans, and its PK characteristics were similar to results previously reported in Americans.

Clozapine prescription rates in Southeast Europe: A cross-sectional study

Introduction

International reports indicate that clozapine is under prescribed. Yet, this has not been explored in Southeast European (SEE) countries. This cross-sectional study investigates clozapine prescription rates in a sample of 401 outpatients with psychosis from Bosnia and Herzegovina, Kosovo by United Nations resolution, North Macedonia, Montenegro and Serbia.

Methods

Descriptive analysis was used to explore clozapine prescription rates; daily antipsychotic dosage was calculated and converted into olanzapine equivalents. Patients receiving clozapine were compared to those not receiving clozapine; next those that were on clozapine monotherapy were compared to those who were on clozapine polytherapy regime.

Results

It was showed that clozapine was prescribed to 37.7% of patients (with cross-country variation: from 25% in North Macedonia to 43.8% in Montenegro), with average dose of 130.7 mg/daily. The majority of patients on clozapine (70.5%) were prescribed at least one more antipsychotic (the most frequent combination was with haloperidol).

Discussion

Our findings suggested that clozapine prescription rate in SEE outpatients is higher than in Western Europe. The average dose is significantly below the optimal therapeutic dosage recommended by clinical guidelines, and clozapine polytherapy is common. This might indicate that clozapine is prescribed mainly for its sedative effect rather than antipsychotic. We hope that this finding will be taken up by relevant stakeholders to address this non-evidence-based practice.

The Modernization of Clozapine: A Recapitulation of the Past in the United States and the View Forward

PURPOSE

Although clozapine was Food and Drug Administration (FDA) approved more than 3 decades ago, major barriers and gaps in knowledge continue to prevent its effective and safe use. We review modern-day problems encountered with clozapine in the United States (US).

METHODS

Information surrounding current administrative, clinical, research, and technological gaps or barriers related to clozapine use in the US was reviewed.

FINDINGS

The history of how clozapine became FDA approved likely contributes to gaps in knowledge. The frequency of safety warnings added to the FDA prescribing information may add to fears about clozapine, as evidence by numerous published survey studies. The clozapine Risk Evaluation and Mitigation Strategy (REMS) program has been modified several times in the last decade, causing access and safety issues for patients, which are discussed. Evidence may suggest that the FDA REMS requirements for hematologic monitoring are too cumbersome, and there may be ability to safely loosen requirements. The COVID-19 pandemic brought forth the ability for extended interval monitoring but also greater awareness of the clozapine-inflammation interaction. Newer guidelines published describe considerations in personalizing clozapine titration based on principles of ethnopsychopharmacology. Emerging technologies to support the use of clozapine are not widely available.

IMPLICATIONS

Clozapine is a unique life-saving drug but it is underused in the US, despite its established efficacy. The 2021 REMS changes led to significant difficulties for providers and patients. We highlight the importance of the clozapine-inflammation interaction, therapeutic drug monitoring, and the ability for individual care based on patient-specific factors. There is an urgent need for advancing technology used for clozapine monitoring, evaluating barriers created by REMS, and establishing consistent practices throughout the US.

A systematic review on the use of clozapine in treatment of tardive dyskinesia and tardive dystonia in patients with psychiatric disorders

RATIONALE

Though clozapine is recommended for treatment of tardive dyskinesia (TD) relating to the use of antipsychotic medications, studies comprehensively investigating the treatment effect of clozapine on TD are still limited.

OBJECTIVES

This review examines the effectiveness of clozapine as an intervention for tardive dyskinesia and dystonia in patients with all psychiatric conditions. Effectiveness of clozapine, duration to exert the effect and dosage used were also analysed.

METHODS

A search in the PubMed, PsycINFO and clinicaltrials databases was performed, using the search terms "Clozapine" AND "dyskinesia" OR "dystonia". Full-text articles that reported the use of clozapine to treat abnormal involuntary movements and were written in English were included.

RESULTS

A total of 48 studies were identified, of which 13 were clinical trials and 35 were case reports. Significant improvement was seen in 86.7% of patients with schizophrenia spectrum disorders (average dose of clozapine = 355 mg/day) and 93% of patients with other psychiatric disorders (average dose of clozapine = 152.5 mg/day). Patients with other psychiatric diagnoses had faster improvement than the patients with schizophrenia spectrum disorders. Variation in improvements and dosage were also seen in the clinical trials.

CONCLUSION

Results suggested an overall effectiveness of clozapine in the treatment of TD for patients with a range of psychiatric conditions. Different response time and clozapine dosage were seen in patients with different psychiatric conditions, suggesting different treatment protocols are required for different conditions. Most of the studies identified are of inadequate qualities, highlighting the need for high quality studies to provide clearer evidence.

Pathophysiology, prognosis and treatment of tardive dyskinesia

Tardive dyskinesia (TD), a movement disorder associated with antipsychotics, most frequently affects the lower face and jaw muscles, but can also affect walking, breathing and use of the hands and limbs. Knowledge of TD among physicians may be limited, and the pathophysiology of TD is poorly understood. We conducted this review to summarise the current knowledge surrounding the pathophysiology of TD and present recommendations for prevention and treatment based on a literature search and roundtable discussion attended by psychiatrists in Japan. It has been suggested that dopamine hypersensitivity, damaged gamma-aminobutyric acidergic neurons and/or increased production of reactive oxygen species may contribute to development of TD. Symptoms can profoundly affect everyday life; patients who develop TD have poorer prognoses, worse health-related quality of life, greater social withdrawal and higher mortality than patients without TD. Traditional treatment options include dietary supplements, although evidence for their effectiveness is low. Among pharmaceutical interventions, there is moderate evidence that switching to the second-generation antipsychotic clozapine, which has a lower affinity for dopamine D2 receptors than other antipsychotics, may improve symptoms. Vesicular monoamine transporter 2 (VMAT-2) inhibitors, which oppose the increased dopaminergic activity associated with prolonged antipsychotic use by interfering with dopamine uptake and storage, have the strongest evidence for efficacy. VMAT-2 inhibitors are approved in the United States for the treatment of TD, and the first VMAT-2 inhibitor was approved in Japan for this indication in March 2022. Most guidelines recommend treating TD by first reducing the dose of antipsychotics or switching to clozapine or other second-generation antipsychotics, which have a lower association with TD than first-generation antipsychotics. We recommend focusing on prevention and monitoring for TD when prescribing antipsychotics, given that TD is often irreversible. Physicians should treat with antipsychotics only when necessary and at the lowest effective dose, and frequently monitor for TD symptoms.

Plain Language Summary

Plain Language Summary (In Japanese).

Visual Summary

Visual Summary (In Japanese).

Switching from blonanserin tablets to blonanserin transdermal patches improves tardive dyskinesia: A case report

Tardive dyskinesia (TD) is a common side effect of antipsychotics, and it remains a persistent and challenging problem. The blonanserin transdermal patch, developed in Japan and launched in September 2019, is the first antipsychotic transdermal treatment. Here, we describe a patient with schizophrenia who exhibited markedly improved orofacial dyskinesia after switching from blonanserin tablets to blonanserin transdermal patches. We speculate that the patch formulation might have led to more stable plasma blonanserin levels, thus reducing the side effects. Specifically, the patch formulation might have contributed to stable plasma levels via the continuous and direct absorption of blonanserin through the skin.

The present case report shows that switching from blonanserin tablets to blonanserin patches may reduce EPSs while maintaining a good therapeutic effect.

Ameliorating schizophrenia-like symptoms in vasopressin deficient male Brattleboro rat by chronic antipsychotic treatment

Due to its various function vasopressin has been associated with many psychiatric disorders, including schizophrenia. Our previous study confirmed that vasopressin-deficient (di/di) Brattleboro rat can be a good genetic model for schizophrenia. Our present aim was to confirm whether the treatment effects of marketed antipsychotics are similar in di/di rats to those seen in human schizophrenic patients. Chronic subcutaneous administration of aripiprazole (5 mg/kg), clozapine (1 mg/kg), haloperidol (0.1 mg/kg), olanzapine (0.3 mg/kg) or risperidone (0.25 mg/kg) was used for 15 days in control (+/+ Brattleboro) and di/di rats. Social discrimination, social avoidance and prepulse inhibition tests were conducted on day 1, 8 and 15 of the treatment. Vasopressin-deficient rats showed social memory- and sensorimotor gating deficit. All used antipsychotics successfully normalized the reduced prepulse inhibition of di/di animals. However, most were effective only after prolonged treatment. Aripiprazole, clozapine, and olanzapine normalized the social memory deficit, while the effects of haloperidol and risperidone were not unequivocal. All drugs reduced social interest to some extent both in control and in di/di animals, aripiprazole being the less implicated in this regard during the social avoidance test. The restoration of schizophrenia-like behavior by antipsychotic treatment further support the utility of the vasopressin-deficient Brattleboro rat as a good preclinical model. Reduced social interest might be a general side-effect of antipsychotics, and aripiprazole has the most favorable profile in this regard.

A Low Clozapine Dose Improved Refractory Tardive Dystonia without Exacerbating Psychiatric Symptoms: A Case Report

Clozapine is recommended for patients with schizophrenia and tardive dystonia (TD); however, the appropriate dose remains unclear. In this case, a low dose (150 mg/day) of clozapine improved refractory TD and further ameliorated psychiatric symptoms. Herein, we report on a 41-year-old female with schizophrenia and TD who was treated with a low clozapine dose. After eight weeks of continuous clozapine at 150 mg/day (16 weeks after clozapine initiation), her TD dramatically improved, and her psychiatric symptoms were relieved. Low clozapine doses could ameliorate refractory TD. However, this effect might require up to several weeks. Clinicians should be patient unless they consider it better to increase the clozapine dose.

An evaluation of the variation and underuse of clozapine in the United Kingdom

BACKGROUND

Clozapine is the only licensed treatment for treatment refractory schizophrenia. Despite this, it remains grossly underused relative to the prevalence of refractory schizophrenia. The extent of underuse and the degree of regional variation in prescribing in the United Kingdom is unknown. It is also unclear, how the UK compares with other European countries in rates of clozapine prescribing.

METHODS

We obtained data relating to all clozapine prescribing in the UK from the relevant clozapine registries. We examined regional variation in clozapine use across England, corrected for the known prevalence of severe mental illness (SMI). We also compared the UK rate of clozapine use per 100,000 population to that described in other European countries.

FINDINGS

There is substantial variation in clozapine prescribing across different regions of England and only about a third of potentially eligible patients were prescribed the drug in the UK. Clozapine prescribing rate in the UK was lower than in several European countries.

INTERPRETATION

There is clear regional inequity in access to the most effective treatment in refractory schizophrenia in England. Strategies to increase clozapine use, by overcoming both real and perceived barriers, are urgently necessary to reduce treatment inequity for patients with refractory schizophrenia.

Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry for Simultaneous Determination of Antipsychotic Drugs in Human Plasma and Its Application in Therapeutic Drug Monitoring

PURPOSE

We developed and validated an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for simultaneous therapeutic drug monitoring (TDM) and clinical pharmacokinetic antipsychotic drugs: clozapine (CLP), chlorpromazine (CPZ), risperidone (RPD), paliperidone (PLD), quetiapine (QTP;), aripiprazole (APZ), dehydroaripiprazole (DAP), olanzapine (OZP), ziprasidone (ZRD), and amisulpride (ASP).

METHODS

Analytes and internal standards (ISs) were separated using a Phenomenex phenyl-hexyl column (50.0 × 2.1 mm, 1.7 μm) with water containing 0.1% formic acid and 2 mM ammonium acetate, and methanol containing 0.1% formic acid and 2 mM ammonium acetate as the mobile phase. The antipsychotic drugs and ISs were extracted from 50 μL of plasma using acetonitrile.

RESULTS

The calibration ranges were 25.0-1500.0 ng/mL for CLP, CPZ, DAP, and QTP, 10.0-600.0 ng/mL for CPZ and ZRD, 2.5-150.0 ng/mL for RPD, 5.0-300.0 ng/mL for PLD and OZP, and 20.0-1200.0 ng/mL for ASP. Validation was carried out according to the guidelines for bioanalytical validation, including assessment of calibration curves, specificity, accuracy, precision, recovery, stability, dilution integrity, and matrix effect. All the results satisfied the requirements.

CONCLUSION

The results provided significant information to support future clinical TDM and rational drug use research. The proposed method also provided a simple, reliable, specific, and suitable technique for TDM and pharmacokinetic studies.

Tardive Dyskinesia: Spotlight on Current Approaches to Treatment

Tardive dyskinesia (TD) is a debilitating, iatrogenic, and potentially severe movement disorder characterized by involuntary, repetitive, purposeless movements that are present throughout the body. The authors present a review of studies of past, current, and possible future treatment approaches to the management of TD; consider the phenomenology, assessment, and putative pathophysiological mechanisms of TD, early pharmacological trials, a focus on the newer vesicular monoamine transporter 2 inhibitors, and other evidence-based approaches, such as clozapine; and present preliminary evidence for newer approaches, such as deep brain stimulation and repetitive transcranial magnetic stimulation. On the basis of the evidence presented here, the authors highlight the importance of early recognition and assessment of TD, as well as how to best approach management of these often incapacitating symptoms.

Continuous versus extended antipsychotic dosing in schizophrenia: Less is more

Antipsychotic drugs temper psychotic symptoms by interacting with dopamine D2 receptors to reduce dopamine neurotransmission. Currently, the standard of care involves antipsychotic treatment protocols that achieve steady-state levels of medication. Maintaining patients on continuous treatment is thought to be necessary to keep them stabilised. However, continuous antipsychotic exposure increases the risk of adverse effects over time. These effects include metabolic and cardiovascular disorders, extrapyramidal complications, and dopamine receptor supersensitivity, the latter of which could potentially promote both treatment tolerance and psychosis relapse. In the present review, we describe evidence showing that continuous exposure to antipsychotic drugs can not only worsen long-term outcome, but-past acute phase treatment-it is also unnecessary to effectively manage schizophrenia symptoms. We also describe evidence that regular but extended dosing, allowing predictable periods of lower antipsychotic levels/D2 occupancy, is both safe and effective in patients, and it greatly reduces drug exposure overall. Studies in laboratory animals show that compared to continuous antipsychotic exposure, regular but extended dosing actually has superior antipsychotic-like efficacy, and it also substantially reduces the likelihood of both motor side effects and dopamine receptor supersensitivity. We propose that regular, but extended dosing should be considered in the long-term treatment of people with schizophrenia, because the available evidence suggests it can be just as effective as continuous treatment, while decreasing overall drug exposure and potentially reducing harmful side effects.

Management of Tardive Syndrome: Medications and Surgical Treatments

Tardive syndrome (TS) is an iatrogenic, often persistent movement disorder caused by drugs that block dopamine receptors. It has a broad phenotype including movement (orobuccolingual stereotypy, dystonia, tics, and others) and nonmotor features (akathisia and pain). TS has garnered increased attention of late because of the Food and Drug Administration approval of the first therapeutic agents developed specifically for this purpose. This paper will begin with a discussion on pathogenesis, clinical features, and epidemiology. However, the main focus will be treatment options currently available for TS including a suggested algorithm based on current evidence. Recently, there have been significant advances in TS therapy, particularly with the development of 2 new vesicular monoamine transporter type 2 inhibitors for TS and with new data on the efficacy of deep brain stimulation. The discussion will start with switching antipsychotics and the use of clozapine monotherapy which, despite the lack of higher-level evidence, should be considered for the treatment of psychosis and TS. Anti-dyskinetic drugs are separated into 3 tiers: 1) vesicular monoamine transporter type 2 inhibitors, which have level A evidence, are approved for use in TS and are recommended first-choice agents; 2) drugs with lower level of evidence for efficacy including clonazepam, Ginkgo biloba, and amantadine; and 3) drugs that have the potential to be beneficial, but currently have insufficient evidence including levetiracetam, piracetam, vitamin B6, melatonin, baclofen, propranolol, zolpidem, and zonisamide. Finally, the roles of botulinum toxin and surgical therapy will be examined. Current therapies, though improved, are symptomatic. Next steps should focus on the prevention and reversal of the pathogenic process.

Tardive syndromes

Dopamine receptor-blocking antipsychotics, first introduced into clinical practice in 1952, were hailed as a panacea in the treatment of a number of psychiatric disorders. However, within 5 years, this notion was to be shattered by the recognition of both acute and chronic drug-induced movement disorders which can accompany their administration. Tardive syndromes, denoting the delayed onset of movement disorders following administration of dopamine receptor-blocking (and also other) drugs, have diverse manifestations ranging from the classic oro-bucco-lingual dyskinesia, through dystonic craniocervical and trunk posturing, to abnormal breathing patterns. Although tardive syndromes have been an important part of movement disorder clinical practice for over 60 years, their pathophysiologic basis remains poorly understood and the optimal treatment approach remains unclear. This review summarises the current knowledge relating to these syndromes and provides clinicians with pragmatic, clinically focused guidance to their management.

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.