Clozapine-olanzapine: a potentially dangerous switch. A report of two cases

Management of Cholinergic Rebound After Abrupt Withdrawal of Clozapine: A Case Report and Systematic Literature Review

BACKGROUND

Cholinergic discontinuation symptoms, also known as "cholinergic rebound," from abrupt clozapine discontinuation are characterized by a range of somatic and psychiatric symptoms.

OBJECTIVE

The objective of this study was to describe the clinical features and management options for clozapine withdrawal-associated cholinergic rebound syndrome (henceforth referred to as CWCRS) and present an illustrative case report.

METHODS

Based on a literature search of the databases PubMed, OVID Medline, and Embase as well as reviewing reference lists of relevant past reviews, we carried out a systematic review of case reports on the management of CWCRS from 1946 to 2023.

RESULTS

We identified 10 previously published articles on the clinical management of CWCRS, with a total of 18 patients (6 female, 12 male) with an average age of 43 years (standard deviation 14). Half of the patients had a history of tardive dyskinesia. The mean dose of clozapine before discontinuation was 351 mg/day, with duration of clozapine treatment ranging from 3 weeks to 9 years. Clozapine was the most effective treatment, followed by benztropine.

CONCLUSIONS

Given the small number of cases and the nonexperimental nature of the available studies, this review could not provide reliable data to guide management of CWCRS. The findings, however, suggest that clozapine may be more effective than other commonly used treatment options. With the high rates of discontinuation among patients on clozapine, there is a pressing need for further research into the epidemiology, natural history, and management of clozapine withdrawal syndromes.

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

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

Clozapine discontinuation withdrawal symptoms in schizophrenia

Clozapine is an atypical antipsychotic used in treatment-resistant schizophrenia. Whilst clozapine is highly effective, there are some clinical scenarios, such as the emergence of severe side effects, that necessitate its discontinuation. There is an emerging literature suggesting that discontinuing antipsychotics, in particular clozapine, can cause an array of withdrawal symptoms. We review the evidence for the existence of clozapine-induced withdrawal symptoms, and in particular focus on withdrawal-associated psychosis, cholinergic rebound, catatonia and serotonergic discontinuation symptoms. To date, there has been surprisingly little clinical guidance on how to minimise the likeliness of withdrawal symptoms in patients who are stopped on clozapine abruptly or gradually. We discuss the key outstanding questions in this area and why there is a need for guidance on the management of withdrawal symptoms associated with clozapine discontinuation.

A case report of cholinergic rebound syndrome following abrupt low-dose clozapine discontinuation in a patient with type I bipolar affective disorder

BACKGROUND

Rebound cholinergic syndrome is a rare, but well known unwanted phenomenon occurring after abrupt clozapine discontinuation. There have been previous reported cases of cholinergic rebound in the literature; however, these reports described cholinergic rebound following cessation of high doses of clozapine in patients diagnosed with schizophrenia. Here, we report a case of rebound cholinergic syndrome and catatonia in a male patient three days after abrupt discontinuation of 50 mg of clozapine prescribed for type I bipolar affective disorder.

CASE PRESENTATION

A 66-year old male of Spanish origin, treated for type I bipolar affective disorder for 15 years and for Crohn disease, was brought to the emergency department because of a sudden onset of mutism, dysphagia and trismus. He was described catatonic and presented hypertension, tachycardia and tachypnea. His body temperature was normal and the laboratory tests were unremarkable at presentation. A head CT and an EEG were in the normal range. While reviewing his history, it appeared the he was on clozapine 50 mg a day, first introduced 2 months ago, during a previous hospitalization for a manic episode resistant to other mood stabilizers. For an unknown reason, the patient's psychiatrist stopped clozapine three days before the admission and replaced it by risperidone 5 mg and quetiapine 200 mg daily. A cholinergic rebound syndrome was then evoked. The patient's ability to speak recovered dramatically and fast after the intravenous administration of 2.5 mg of biperiden supporting the diagnosis. Risperidone and quetiapine were also stopped. The patient fully recovered in 20 days after the reintroduction of 50 mg of clozapine and 2.5 mg of biperiden daily.

CONCLUSIONS

This case report underscores that cholinergic rebound syndrome may occur in patients suffering from bipolar affective disorders, being on clozapine as a mood stabilizer. The low dose clozapine does not preclude severe manifestations of the phenomenon. Progressive tapering should therefore be adopted in any case.

Current and potential pharmacological and psychosocial interventions for anxiety symptoms and disorders in patients with schizophrenia: structured review

OBJECTIVE

Between 30% and 62% of patients with schizophrenia present with co-morbid anxiety disorders that are associated with increased overall burden. Our aim was to summarize current and potential interventions for anxiety in schizophrenia.

DESIGN

Structured review, summarizing pharmacological and psychosocial interventions used to reduce anxiety in schizophrenia and psychosis.

RESULTS

Antipsychotics have been shown to reduce anxiety, increase anxiety, or have no effect. These may be augmented with another antipsychotic, anxiolytic, or antidepressant. Novel agents, such as L-theanine, pregabalin, and cycloserine, show promise in attenuating anxiety in schizophrenia. Psychosocial therapies have been developed to reduce the distress of schizophrenia. Cognitive behavioural therapy (CBT) has shown that benefit and refinements in the therapy have been successful, for example, for managing worry in schizophrenia. CBT usually involves more than 16 sessions, as short courses of CBT do not attenuate the presentation of anxiety in schizophrenia. To address time and cost, the development of manualized CBT to address anxiety in schizophrenia is being developed.

CONCLUSIONS

The presence of coexisting anxiety symptoms and co-morbid anxiety disorders should be ascertained when assessing patients with schizophrenia or other psychoses as a range of pharmacological and psychosocial treatments are available.

Withdrawal symptoms and rebound syndromes associated with switching and discontinuing atypical antipsychotics: theoretical background and practical recommendations

With the widespread use of atypical or second-generation antipsychotics, switching treatment has become current practice and more complicated, as the pharmacological profiles of these agents differ substantially despite their similarity in being 'atypical'. All share the ability to block dopamine D₂ receptors, and most of them also block serotonin 5-HT2A receptors. Apart from these common features, some atypical antipsychotics are also able to block or stimulate other dopamine or serotonin receptors, as well as histaminergic, muscarinergic or adrenergic receptors. As a result of the varying receptor affinities, in switching or discontinuing compounds several possible pitfalls have to be considered, including the occurrence of withdrawal and rebound syndromes. This article reviews the pharmacological background of functional blockade or stimulation of receptors of interest in regard to atypical antipsychotics and the implicated potential withdrawal and rebound phenomena. A MEDLINE search was carried out to identify information on withdrawal or rebound syndromes occurring after discontinuation of atypical antipsychotics. Using the resulting literature, we first discuss the theoretical background to the functional consequences of atypical antipsychotic-induced blockade or stimulation of neurotransmitter receptors and, secondly, we highlight the clinical consequences of this. We then review the available clinical literature on switching between atypical antipsychotics, with respect to the occurrence of withdrawal or rebound symptoms. Finally, we offer practical recommendations based on the reviewed findings. The systematic evaluation of withdrawal or rebound phenomena using randomized controlled trials is still understudied. Knowledge of pharmacological receptor-binding profiles may help clinicians in choosing adequate switching or discontinuation strategies for each agent. Results from large switching trials indicate that switching atypical antipsychotics can be performed in a safe manner. Treatment-emergent adverse events during or after switching are not always considered to be, at least in part, associated with the pre-switch antipsychotic. Further studies are needed to substantiate the evidence gained so far on different switching strategies. The use of concomitant medication, e.g., benzodiazepines or anticholinergic drugs, may help to minimize symptoms arising from the discontinuation or switching of antipsychotic treatment.

Practical guidelines for the use of new generation antipsychotic drugs (except clozapine) in adult individuals with intellectual disabilities

New generation antipsychotic (NGA) drugs introduced to the US market after clozapine (aripiprazole, olanzapine, paliperidone, quetiapine, risperidone, and ziprasidone) are frequently used in individuals with intellectual disabilities (ID). However, there is very limited research to fully establish evidence-based or personalized medicine approaches for their use in this population. These guidelines take a pragmatic approach to establishing frameworks for their use by utilizing the prescribing information and reviewing the available literature on other relevant neuropsychiatric disorders. In the absence of expert consensus guidance and well-controlled comparison trials, we present a set of guidelines to inform initiation, dosing and monitoring of use in adults. Further, in these guidelines we provide practical information on drug-drug interactions and adverse drug reactions, and a brief review of discontinuation syndromes, potential for abuse, use during pregnancy and cost considerations. We also provide drug utilization review forms for each NGA to facilitate implementation of these guidelines, these guidelines provide a practical and necessary resource for practitioners treating psychiatric disorders and challenging behaviors in adult individuals with ID.

Switching antipsychotics: an updated review with a focus on quetiapine

Atypical antipsychotics offer broader efficacy and improved tolerability compared with conventional agents. Many patients currently treated with conventional antipsychotics continue to experience persistent symptoms or troublesome side effects and may benefit from a change to one of the newer atypical agents. There are also significant differences in the side-effect profiles of the atypicals, such that a switch from one atypical agent to another could offer advantages to many patients. Unfortunately, many clinicians remain uncertain about the switching process and are reluctant to initiate change. The aim of this review is to identify the indications for a switch in antipsychotic therapy with a focus on recent switching data for the atypical antipsychotic, quetiapine. The clinical aspects of quetiapine's receptor binding characteristics are reviewed including the implications of the low D(2) antagonist properties that make quetiapine the treatment of choice when EPS persists with other atypical antipsychotics. Practical guidelines are given for managing the process of changeover, for avoiding pitfalls and for maximizing the chances of a successful switch. For example, when managing the antipsychotic crossover, it is important to consider the psychological effects of switching arising from symptom and side-effect changes. Finally, advice is provided on the assessments necessary when evaluating the success of a change in therapy, together with guidance on the optimal duration of treatment trials.

Switching between second-generation antipsychotics: why and how?

The introduction of second-generation antipsychotics represents an important advance in the treatment of schizophrenia. Although these drugs are generally very effective, not all patients respond in the same way. Partial response with persistent positive and negative symptoms and residual symptoms may force physicians to change antipsychotic medication. As more and more second-generation antipsychotics are introduced, the need for practical guidelines on switching these medications becomes increasingly important. In this article we provide a short summary of the second-generation antipsychotics, focusing on efficacy, adverse effect profile and safety. Indications for switching antipsychotic medication are outlined, as well as recommendations when switching is disadvantageous. Three basic switching strategies (abrupt, gradual and overlapping switching) and their potential risks and benefits are described. We review the available evidence concerning techniques, problems and consequences when switching from one second-generation antipsychotic agent to another and discuss potential difficulties.

Switching atypical antipsychotics: a review

BACKGROUND

Atypical antipsychotics are increasingly used in the treatment of diverse psychiatric disorders; however, there is little information on the 'why, when, and how' of switching between the different atypical antipsychotics currently available.

OBJECTIVE

To review the data on switching and atypical antipsychotics.

METHODS

A literature search was initially conducted using the key words followed by a search of relevant articles including conference abstracts; relevant pharmaceutical companies were also contacted.

RESULTS

Clinical trial data are limited in terms of parameters measured, and case reports describe specific problems. Few studies are based on real world populations of psychiatric patients over the long-term. Careful patient and drug selections matched to a carefully supervised and appropriate cross titration based upon the pharmacodynamic and pharmacokinetic properties of all of the drugs involved is important to avoid potential complications such as re-emergence or worsening of psychosis and withdrawal, rebound, and emergent phenomena including new or uncovered side-effects. Psychoeducation and involvement of patients and caregivers in the process are also necessary for a successful switch.

CONCLUSION

Despite the prevalence of switching in real world clinical practice, there is a paucity of data to guide clinicians with respect to effective and safe strategies. There are no criteria defining a successful switch. With the increasing range and formulations of atypical antipsychotics available, there is a rationale for their early use to avoid the practical problems associated with switching from conventional antipsychotics as well as the opportunity to maintain patients on an optimal atypical antipsychotic monotherapy.

Olanzapine in Chinese treatment-resistant patients with schizophrenia: an open-label, prospective trial

The role of olanzapine in treatment-resistant schizophrenia has still not been clearly resolved. In addressing this issue, the current report presents an open-label, prospective, 13 week trial with olanzapine use in Chinese schizophrenic patients who were resistant to more than two different classes of antipsychotics during a minimal 4 week treatment period for each antipsychotic drug at adequate dosage. Fifty-one inpatients were recruited after a cross-titration period and given 10-25 mg of olanzapine daily, without any concomitant antipsychotic medication. Patients were evaluated with the Brief Psychotic Rating Scale (BPRS), the Positive and Negative Symptoms Scale, the Clinical Global Impression Scale (CGI), the Abnormal Involuntary Movement Scale, the Simpson-Angus scale, and the Barnes Akathisia Scale. The olanzapine-treated patients showed significant improvement in both the positive and negative symptoms of schizophrenia by the end of the study. Overall, 20 of 51 (39.2%) responded to 10-25 mg of olanzapine per day as measured by the BPRS and CGI scores. Five patients dropped out due to the worsening of their psychotic symptoms, two patients discontinued owing to poor drug compliance, and the remaining patient complained of a lack of efficacy. Extrapyramidal side-effects were mild, and anticholinergic medications required has decreased. The present open study suggests that olanzapine may be effective and well-tolerated in Chinese treatment-resistant schizophrenic patients. Further double-blinded trials are needed to confirm this result.

Refractory schizophrenia and atypical antipsychotics

Treatment resistant or refractory schizophrenia is a difficult to define condition of largely unknown prevalence. For 10 years, clozapine has been the standard treatment in this condition and is recognized unequivocally as being effective. However, clozapine is sometimes poorly tolerated and has the potential for severe toxicity. Partly as a result of this, other atypicals have recently been evaluated as treatments for refractory schizophrenia. In order to evaluate the evidence base relating to the drug treatment of refractory schizophrenia, we developed a refractoriness rating based on previous work. Using this rating, we assessed all trials of atypicals in schizophrenia unresponsive to at least one drug. Overall, clozapine was consistently shown to be effective in refractory schizophrenia, even when stringently defined. Data relating to olanzapine and risperidone are equivocal at best, and there is some evidence to suggest that they are less effective than clozapine. There is essentially no cogent evidence to support the use of any other atypical in refractory schizophrenia. Clozapine remains the drug of choice in this condition.