Clozapine withdrawal resulting in delirium with psychosis: a report of three 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.

Serotonin syndrome caused by a CYP2C19-mediated interaction between low-dose escitalopram and clopidogrel: a case report

Background

Serotonin syndrome has been recognized as a serious adverse reaction to antidepressants and is characterized by sudden or severe autonomic nerve dysfunction and neuromuscular symptoms. Without an accurate diagnosis and prompt treatment, serotonin syndrome progresses rapidly and can be life-threatening. It is usually related to the dose of 5-hydroxytryptamine drugs, and the dose is the basis for diagnosis. Therefore, serotonin syndrome induced by low-dose antidepressants rarely occurs, and clinicians are more likely to misdiagnose patients who take low-dose antidepressants with similar symptoms. Here, we present a case study of serotonin syndrome caused by a relatively low dose of escitalopram, which is not common in past references.

Case summary

The patient was a 74-year-old Asian woman with a 42-year history of schizophrenia. After 6 weeks of antidepressant treatment, our patient presented with characteristic myoclonus in the lower limbs and closed eyes with fluttering. Initially, she was misdiagnosed with neuroleptic malignant syndrome (NMS) due to antipsychotic medication and was treated accordingly, even with discontinuation of clozapine. However, her symptoms persisted, and then therapeutic drug monitoring was initiated with the involvement of a clinical pharmacist. Eventually, she was diagnosed with serotonin syndrome due to escitalopram levels reaching the warning level. Subsequently, the patient's treatment was modified, and her clinical outcome was satisfactory without any other serious adverse reactions. Gene detection was also performed, and a cytochrome P450 enzyme (CYP) 2C19-mediated interaction between low-dose escitalopram and clopidogrel seems to be a possible mechanism.

Conclusion

Data on this is extremely scarce, and to the best of our knowledge, serotonin syndrome caused by low-dose antidepressants has not yet been discussed to any great extent in the literature. Our case provides more clinical experience in the treatment of serotonin syndrome.

The introduction of clozapine at the Nathan Kline Institute in New York and its long-term consequences

Nathan S. Kline was a pioneer in psychopharmacology in the United States (US). In 1952, Kline started a research unit at Rockland State Hospital, New York. Kline brought clozapine from Switzerland since it was not yet available in the US. At Rockland State Hospital, George Simpson had conducted antipsychotic trials and had developed scales to assess movement disorders. In 1974, Simpson published the first US clozapine trial. In 1978, he published on 1) the effect of clozapine on tardive dyskinesia and 2) high plasma clozapine concentrations in two patients with seizures. His experience of clozapine withdrawal symptoms in his first 2 trials led in the future to more articles in this area. In Philadelphia, Simpson designed a double-blind randomized clinical trial (RCT) with 3 doses (100, 300 and 600 mg/day) which was published in 1999. From the 50 patients started on the RCT, 47 provided repeated plasma clozapine concentrations every other week of the RCT. This rich database of plasma clozapine concentrations under controlled conditions has contributed to many of the advances in clozapine pharmacokinetics in the last 5 years including: 1) obesity can be associated with clozapine poor metabolism (PM) status, 2) a clozapine ultrarapid metabolizer (UM) with a minimum therapeutic dose of 1591 mg/day, 3) a case of clozapine intoxication dropped from the RCT due to pneumonia, 4) cases of increased plasma concentrations during clozapine-induced fever, 5) the possibility that African-Americans may need higher clozapine doses than those of European ancestry, and 6) three indices of non-adherence.

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.

Recognition and management of clozapine adverse effects: A systematic review and qualitative synthesis

OBJECTIVE

Clozapine is substantially underutilized in most countries and clinician factors including lack of knowledge and concerns about adverse drug effects (ADEs) contribute strongly to treatment reluctance. The aim of this systematic review was to provide clinicians with a comprehensive information source regarding clozapine ADEs.

METHODS

PubMed and Embase databases were searched for English language reviews concerned with clozapine ADEs; publications identified by the automated search were manually searched for additional relevant citations. Following exclusion of redundant and irrelevant reports, pertinent information was summarized in evidence tables corresponding to each of six major ADE domains; two authors reviewed all citations for each ADE domain and summarized their content by consensus in the corresponding evidence table. This study was conducted in accordance with PRISMA principles.

RESULTS

Primary and secondary searches identified a total of 305 unique reports, of which 152 were included in the qualitative synthesis. Most clozapine ADEs emerge within 3 months, and almost all appear within 6 months, after initiation. Notable exceptions are weight gain, diabetic ketoacidosis (DKA), severe clozapine-induced gastrointestinal hypomotility (CIGH), clozapine-induced cardiomyopathy (CICM), seizures, and clozapine-induced neutropenia (CIN). Most clozapine ADEs subside gradually or respond to dose reduction; those that prompt discontinuation generally do not preclude rechallenge. Rechallenge is generally inadvisable for clozapine-induced myocarditis (CIM), CICM, and clozapine-induced agranulocytosis (CIA). Clozapine plasma levels >600-1000 μg/L appear more likely to cause certain ADEs (e.g., seizures) and, although there is no clear toxicity threshold, risk/benefit ratios are generally unfavorable above 1000 μg/L.

CONCLUSION

Clozapine ADEs rarely require discontinuation.

Fluctuation between cigarette smoking and use of electronic nicotine delivery systems: Impact on clozapine concentrations and clinical effect

Unlike with smoking cigarettes, electronic nicotine delivery systems do not cause CYP450 1A2 induction as there is a lack of combustion and polycyclic aromatic hydrocarbon production. Changing to the use of an electronic nicotine delivery system from cigarettes can result in the deinduction of CYP450 1A2 and the increase of certain medication serum concentrations, including clozapine. A case is reported in which the switch from smoking to an electronic nicotine delivery system resulted in increased clozapine serum concentration and constipation, necessitating pharmacologic management. The patient ultimately transitioned back to cigarettes, which resulted in the emergence of psychiatric symptoms. An evaluation of longitudinal serum concentrations and clinical correlation is provided. It is important that patients and health care professionals have knowledge not only about the impact of smoking cigarettes on clozapine metabolism, but also the effects of switching to or from an electronic nicotine delivery system.

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.

Effects of Curcumin on Depression and Anxiety: A Narrative Review of the Recent Clinical Data

Depressive and anxiety disorders affect a significant proportion of the global population and constitute one of the highest disease burdens worldwide. Conventional pharmacological treatments are traditionally the first line of therapy for individuals affected by these conditions although these are only successful approximately half of the time and are often associated with undesirable side effects. This review describes the use of the natural substance curcumin as a potential alternative treatment of these mental disorders. With this in mind, we analyzed the effects of curcumin in eight clinical studies of depression and five studies of anxiety and assessed these using psychiatric symptom scores and molecular biomarker readouts.

Clozapine Withdrawal-Induced Malignant Catatonia or Neuroleptic Malignant Syndrome: A Case Report and a Brief Review of the Literature

ABSTRACT

In our brief literature review, we discuss the changes in the concept of catatonia as well as its various types and symptoms. We also succinctly review the possible symptoms of clozapine withdrawal. In addition, we analyze the main features of the very few published cases of clozapine withdrawal-induced catatonia and the relationship between neuroleptic malignant syndrome and the malignant subtype of catatonia. Furthermore, we present the case of a 29-year-old male patient with schizophrenia in whom a malignant catatonic episode/neuroleptic malignant syndrome (with negativism, stupor, mutism, autonomic signs [eg, fever, hyperhidrosis], and elevated creatine kinase levels) began 5 days after the patient decided arbitrarily to cease his clozapine treatment. His catatonic symptoms quickly (ie, within a few days) resolved after the reinstitution of clozapine. Finally, we attempt to provide a theoretical explanation for the surprising finding in the literature that the withdrawal of clozapine, unlike the withdrawal of any other antipsychotics, may be associated with catatonia (frequently its malignant subtype). The take-home message of our case is that clinicians should bear in mind the risk of catatonia (especially the malignant subtype of it) after the prompt withdrawal of clozapine therapy.

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.

The report of the joint WPA/CINP workgroup on the use and usefulness of antipsychotic medication in the treatment of schizophrenia

This is a report of a joint World Psychiatric Association/International College of Neuropsychopharmacology (WPA/CINP) workgroup concerning the risk/benefit ratio of antipsychotics in the treatment of schizophrenia. It utilized a selective but, within topic, comprehensive review of the literature, taking into consideration all the recently discussed arguments on the matter and avoiding taking sides when the results in the literature were equivocal. The workgroup's conclusions suggested that antipsychotics are efficacious both during the acute and the maintenance phase, and that the current data do not support the existence of a supersensitivity rebound psychosis. Long-term treated patients have better overall outcome and lower mortality than those not taking antipsychotics. Longer duration of untreated psychosis and relapses are modestly related to worse outcome. Loss of brain volume is evident already at first episode and concerns loss of neuropil volume rather than cell loss. Progression of volume loss probably happens in a subgroup of patients with worse prognosis. In humans, antipsychotic treatment neither causes nor worsens volume loss, while there are some data in favor for a protective effect. Schizophrenia manifests 2 to 3 times higher mortality vs the general population, and treatment with antipsychotics includes a number of dangers, including tardive dyskinesia and metabolic syndrome; however, antipsychotic treatment is related to lower mortality, including cardiovascular mortality. In conclusion, the literature strongly supports the use of antipsychotics both during the acute and the maintenance phase without suggesting that it is wise to discontinue antipsychotics after a certain period of time. Antipsychotic treatment improves long-term outcomes and lowers overall and specific-cause mortality.

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.

Self-Report for Measuring and Predicting Medication Adherence: Experts' Experience in Predicting Adherence in Stable Psychiatric Outpatients and in Pharmacokinetics

THE PROBLEM

Poor adherence to appropriately prescribed medication is a global challenge for psychiatrists.

PRIOR STUDIES

Measuring adherence is complicated. In our recent three-country naturalistic study including more than 1000 patients and their adherence to multiple medication prescriptions at the same time, patients' self-report of adherence to each specific drug was the only practical option for measuring adherence. Systematic literature reviews provide inconsistent results for sociodemographic, clinical and medication variables as predictors of adherence to psychiatric drugs. Our studies over the last 10 years in relatively stable psychiatric outpatients have shown that some self-reported health beliefs had consistent, strong effects and a better predictive role. Three dimensions of these health beliefs are characteristics of the individual: 1) attitudes toward psychiatric medication such as pharmacophobia (fear of taking drugs or medicines), 2) health locus of control (the belief patients have about who or what agent determines the state of their health), 3) psychological reactance (an emotional reaction in direct contradiction to rules or regulations that threaten or suppress certain freedoms in behavior). They can be measured by the Patient Health Beliefs Questionnaire on Psychiatric Treatment. The attitude toward each specific medication can be measured by the necessity-concern framework and summarized as the presence or absence of skepticism about that drug. After 25 years conducting pharmacokinetic studies in psychiatric drugs, particularly antipsychotics, we have limited understanding of how to use blood levels to predict the effects of non-adherence or to establish it.

EXPERT OPINION ON FUTURE STUDIES

Future studies to predict adherence should include the inpatient setting and explore insight. Studying the pharmacokinetics associated with non-adherence in each psychiatric drug is a major challenge. Medication adherence is a complex and dynamic process changing over time in the same patient. Personalizing adherence using psychological or pharmacological variables are in their initial stages.

[Antipsychotic-induced motor symptoms in schizophrenic psychoses-Part 2 : Catatonic symptoms and neuroleptic malignant syndrome]

In rare cases, pharmacotherapy in schizophrenic psychoses can be associated with life-threatening antipsychotic-induced movement disorders. The two most severe complications are antipsychotic-associated catatonic symptoms (ACS) and neuroleptic malignant syndrome (NMS). Although both constellations necessitate rapid medical care, the diagnosis is still a clinical challenge. Although there is no established treatment of ACS (here designated as a specific subtype of catatonic symptoms), an attempt should be made with benzodiazepines and memantine can also be helpful. In severe drug-refractory cases electroconvulsive therapy (ECT) can be indicated. The NMS represents a life-threatening constellation that frequently requires intensive care unit treatment. The medicinal treatment with benzodiazepines, bromocriptine, amantadine, dantrolene and/or ECT is also advocated. Finally, this review article also summarizes the currently available literature for treatment of genuine catatonic symptoms. In conclusion, the abovementioned clinical syndromes must be rapidly recognized and treated. Early recognition and treatment of these movement disorders can under certain circumstances be lifesaving and favorably influence the later clinical outcome.

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.

Catatonia Secondary to Sudden Clozapine Withdrawal: A Case with Three Repeated Episodes and a Literature Review

A literature search identified 9 previously published cases that were considered as possible cases of catatonia secondary to sudden clozapine withdrawal. Two of these 9 cases did not provide enough information to make a diagnosis of catatonia according to the Diagnostic and Statistical Manual, 5th Edition (DSM-5). The Liverpool Adverse Drug Reaction (ADR) Causality Scale was modified to assess ADRs secondary to drug withdrawal. From the 7 published cases which met DSM-5 catatonia criteria, using the modified scale, we established that 3 were definitive and 4 were probable cases of catatonia secondary to clozapine withdrawal. A new definitive case is described with three catatonic episodes which (1) occurred after sudden discontinuation of clozapine in the context of decades of follow-up, (2) had ≥3 of 12 DSM-5 catatonic symptoms and serum creatinine kinase elevation, and (3) required medical hospitalization and intravenous fluids. Clozapine may be a gamma-aminobutyric acid (GABA) receptor agonist; sudden clozapine withdrawal may explain a sudden decrease in GABA activity that may contribute to the development of catatonic symptoms in vulnerable patients. Based on the limited information from these cases, the pharmacological treatment for catatonia secondary to sudden clozapine withdrawal can include benzodiazepines and/or restarting clozapine.

The Treatment of Clozapine-Withdrawal Delirium with Electroconvulsive Therapy

Clozapine, a commonly used atypical antipsychotic, can precipitate a severe withdrawal syndrome. In this report, we describe a case of delirium with catatonic features emerging after the immediate cessation of clozapine subsequent to concerns of developing neuroleptic malignant syndrome. After multiple treatments were found to be inefficacious, electroconvulsive therapy (ECT) was initiated, resulting in significant improvement. A literature search revealed six previous cases of clozapine-withdrawal syndromes of varied symptomatology treated with ECT. To our knowledge, the present case represents the first reported clozapine-withdrawal delirium treated successfully with ECT.

Therapeutic Options in the Treatment of Clozapine-Induced Adverse Effects

Objective:

To review the therapeutic options in the management of clozapine-induced adverse effects.

Data Sources:

A MEDLINE search (from 1966 to present) was conducted, and English-language studies and review articles were retrieved to review the adverse effects of clozapine and their management.

Study Selection and Data Extraction:

All studies evaluating clozapine's adverse effects, such as agranulocytosis, seizures, neuroleptic malignant syndrome, hypersalivation, weight gain, sedation, fatigue, orthostatic hypotension, eosinophilia, delirium, new-onset diabetes, constipation, nausea, tachycardia, myocarditis, and pancreatitis, and their management were included.

Data Synthesis:

Clozapine, an atypical antipsychotic that has been proven effective and comparable, as well as superior, to conventional antipsychotics in treatment-resistant schizophrenia, is also being used in the treatment of a wide variety of other psychiatric conditions, including suicidal ideation, tardive dyskinesia, and affective disorders such as depression, bipolar disorders, and schizoaffective disorder. Although clozapine exhibits a markedly low incidence of extrapyramidal symptoms compared with similar medications, it has other adverse effects, some of which are potentially life threatening, requiring careful monitoring. The adverse effects of clozapine range from benign drooling, weight gain, nausea, and constipation, to life-threatening agranulocytosis, seizures, and neuroleptic malignant syndrome (NMS). Mandatory periodic white blood cell monitoring has resulted in dramatic reduction in mortality due to clozapine-induced agranulocytosis, promoting high adherence by patients. Prompt diagnosis and treatment of adverse effects of clozapine has also been effective in reducing complications, including mortality due to other serious adverse effects such as NMS and seizure. Other adverse effects are comparatively benign and can be managed effectively.

Conclusions:

Clozapine has a wide variety of adverse effects, some of which are potentially life threatening. Clinicians should be aware of possible severe complications and emergency management. Differentiating between minor and major adverse effects and initiating appropriate intervention is essential for a positive therapeutic outcome when prescribing clozapine.

Loxapine and Cyproheptadine Combined Limit Clozapine Rebound Psychosis and May Also Predict Clozapine Response

Clozapine has been consistently shown to be superior to other antipsychotics in the treatment of psychosis. However, clozapine usage has been limited due to required routine blood monitoring and the potential for life threatening side effects. We report a case of a 66-year-old female patient, who developed clozapine-induced agranulocytosis after 10 weeks of clozapine treatment and was subsequently successfully treated with a combination of loxapine and cyproheptadine. The combination is thought to mimic the pharmacological profile of clozapine, rendering it as a possible alternative to traditional clozapine treatment.

An Unusual Case of Delirium after Restarting Clozapine

Clozapine is a gold standard medication and drug of choice in refractory schizophrenia. Among many of its fatal side effects, delirium is less reported and inconsistently recognized by clinicians. We here present a case of delirium which emerged during retreatment with clozapine in a patient of paranoid schizophrenia. A patient diagnosed with paranoid schizophrenia, was restarted on clozapine after he left medications and became symptomatic. He was delirious on 22nd day after clozapine was restarted. Clozapine was stopped and the patient was managed with standard treatment for delirium. After one week interval, clozapine was restarted. Delirium was not noted till 6 weeks of his hospital stay. Clozapine induced central anticholinergic toxicity or clozapine induced seizure might cause delirium in index case. Limited literature exist delirium with clozapine. Clinicians must have high index of suspicion to detect delirium during clozapine therapy. More researches should focus to explore the association between delirium and clozapine.

Neuroleptic malignant syndrome and subsequent clozapine-withdrawal effects in a patient with refractory schizophrenia

Here, we report a female patient developing neuroleptic malignant syndrome following the use of a combination of clozapine and haloperidol. Subsequently, the patient presented withdrawal effects after an abrupt discontinuation of clozapine. Psychiatrists not aware of possible clozapine-withdrawal effects may misdiagnose as a part of the primary mental illness or as the initial symptoms worsening, if unrecognized.

Schizophrenia past clozapine: what works?

Clozapine is superior to other antipsychotic drugs for treatment of refractory schizophrenia. However, its use has been limited by its potentially serious adverse effects. There is little guidance on the management of patients who discontinue clozapine for reasons such as lack of response, intolerance, or noncompliance. The literature was searched for studies on the efficacy of antipsychotics that replaced clozapine in such patients. The search revealed 15 papers, which were evaluated in this article. Olanzapine was the most tested alternative to clozapine with most of the studies reporting positive outcome, especially in patients with less severe illness and those who stop clozapine for reasons other than poor response. Other antipsychotics were not adequately tested in this manner. We concluded that in patients who discontinue clozapine, considering a trial of olanzapine would be worthwhile.

Mechanisms of action of antipsychotic drugs of different classes, refractoriness to therapeutic effects of classical neuroleptics, and individual variation in sensitivity to their actions: Part II

Rapid-onset psychotic rebound is uncommon on discontinuation of most antipsychotic drugs, as might be expected for antipsychotic drugs with (hypothetically) indirect actions at their final target receptors. Rapid-onset psychosis is more common on withdrawal of clozapine, which might be expected if its action is direct. Drugs other than clozapine (notably thioridazine) may have hitherto unrecognised similarities to clozapine (but without danger of agranulocytosis), and may be useful in treatment of refractory psychosis. Quetiapine fulfils only some criteria for a clozapine-like drug. Clinical response to neuroleptics varies widely at any given plasma level. Haase's "neuroleptic threshold" concept suggests that the dose producing the slightest motor side effects produces most or all of the therapeutic benefit, but analyses presented here suggest that antipsychotic actions are not subject to a sharp "all-or-none" threshold but increase over a small dose range. This concept could provide a method for quantitative determination of individualized optimal doses.

An Unusual Cause of Delirium in a Psychiatric Patient: Abrupt Clozapine Discontinuation

Rapid clinical deteriorations have been reported after abrupt discontinuation of clozapine. A 42-year-old psychiatric patient presented with ingestion of hand-disinfectant solutions causing transient impairment of his conscious level. His clozapine therapy was discontinued for a short period of time and he developed delirium with normal results of investigations for underlying organic causes. His delirium resolved rapidly after the reintroduction of clozapine. The withdrawal effects of abrupt discontinuation of clozapine are discussed in this article.

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.

Neurological complications of psychiatric drugs: clinical features and management

This paper reviews the main neurological complications of psychiatric drugs, in particular antipsychotics and antidepressants. Extrapyramidal syndromes include acute dystonia, parkinsonism, akathisia, tardive dyskinesia and tardive dystonia. Extrapyramidal symptoms (EPS) are less frequent with atypical than with conventional antipsychotics but remain common in clinical practice partly due to lack of screening by health professionals. Neuroleptic malignant syndrome (NMS) consists of severe muscle rigidity, pyrexia, change in conscious level and autonomic disturbance but partial forms also occur. NMS is particularly associated with the initiation and rapid increase in dose of high-potency antipsychotics but it has been reported with all the atypical antipsychotics and rarely with other drugs including antidepressants. Serotonin toxicity comprises altered mental state (agitation, excitement, confusion), neuromuscular hyperactivity (tremor, clonus, myoclonus, hyper-reflexia) and autonomic hyperactivity and occurs on a spectrum. Severe cases, termed serotonin syndrome, usually follow the co-prescription of drugs that increase serotonergic transmission by different pathways, for example a monoamine oxidase inhibitor (MAOI) and a selective serotonin reuptake inhibitor (SSRI). Most antipsychotics and antidepressants lower the seizure threshold and can cause seizures; the risk is greater with clozapine than with other atypical antipsychotics and greater with tricyclic antidepressants (TCAs) than with SSRIs. In randomised controlled trials in elderly patients with dementia atypical antipsychotics are associated with a higher risk of stroke and death than placebo. Cohort studies suggest that conventional drugs carry at least the same risk. Cessation of treatment with antipsychotics and antidepressants can lead to a wide range of discontinuation symptoms which include movement disorders and other neurological symptoms. Clinicians need to be familiar with strategies to reduce the risk of these adverse events and to manage them when they arise. Their occurrence needs to be balanced against the benefits of psychiatric drugs in terms of efficacy and improved quality of life in a range of disorders.

Clozapine-induced leukopenia successfully treated with lithium

PURPOSE

A case of clozapine-induced leukopenia successfully treated with lithium is reported.

SUMMARY

A 55-year-old man with paranoid schizophrenia who had been stable on clozapine for more than 10 years was admitted to an inpatient behavioral health unit with leukopenia associated with clozapine use. This patient's history was significant for four previous hospitalizations for psychiatric issues, none of which occurred while he was using clozapine. On admission, the patient's clozapine was discontinued and he was started on olanzapine. On hospital day 4, his white blood cell (WBC) count had risen to 3400/mm(3) and clozapine was resumed due to increasing auditory hallucinations and suicidal ideation. On hospital day 5, his WBC count decreased to 2900/mm(3) and clozapine was again stopped. The patient was given lithium carbonate 300 mg at bedtime, and olanzapine was discontinued. The next day, clozapine was restarted at 12.5 mg daily at bedtime. On hospital day 11, his WBC count had risen to 5400/mm(3). The patient was discharged on clozapine 25 mg at bedtime, with a WBC count of 3400/mm(3). The patient has not been rehospitalized and has not had significant changes in his WBC count or absolute neutrophil count (ANC) for more than 14 months.

CONCLUSION

A 55-year-old man with schizophrenia developed clozapine- induced leukopenia after more than 10 years of treatment. Lithium was used to stimulate leukocyte production, and clozapine was restarted successfully. The patient was maintained on clozapine and lithium without significant changes in his WBC count or ANC.

Quetiapine: efficacy, tolerability and safety in schizophrenia

Quetiapine, a dibenzothiazepine derivative, is an atypical antipsychotic, multireceptor antagonist that has a preclinical profile similar to clozapine. Randomized studies have demonstrated the efficacy of quetiapine relative to placebo in the treatment of acute relapse and the long-term management of schizophrenia. Quetiapine is generally well tolerated relative to other antipsychotic medications, although side effects include sedation, orthostatic hypotension, anticholinergic and metabolic side effects. The purpose of this article is to critically review the current literature on quetiapine with an emphasis on emergent themes and key findings in the use of this agent for the treatment of schizophrenia. There are also continued efforts to understand, predict and manage the side-effect risk with quetiapine.

Does antipsychotic withdrawal provoke psychosis? Review of the literature on rapid onset psychosis (supersensitivity psychosis) and withdrawal-related relapse

OBJECTIVE

To examine the evidence that discontinuation of long-term antipsychotic medication, including clozapine, may provoke a psychotic episode.

METHOD

Databases were searched and citations scrutinised.

RESULTS

Evidence for a rapid onset psychosis (supersensitivity psychosis) following clozapine withdrawal was found and weaker evidence that this might occur with some other antipsychotic drugs. Some cases were reported in people without a psychiatric history. It appears that the psychosis may be a feature of drug withdrawal rather than the re-emergence of an underlying illness, at least in some patients. Meta-analyses of withdrawal studies have suggested that antipsychotic discontinuation may also increase the risk of relapse over and above the risk because of the underlying disorder, but not all individual studies show this effect. Mechanisms may relate to brain adaptations to long-term drug use but data are sparse.

CONCLUSION

These effects require further urgent research. Interventions to reduce morbidity after drug withdrawal need to be developed.

Combating psychosis in Parkinson's disease patients: the use of antipsychotic drugs

Parkinson's disease (PD) patients commonly experience psychotic symptoms, with the most frequent manifestation being visual hallucinations. In PD, psychosis is predominantly drug induced and an important issue for clinicians to address as it increases the risk of nursing home placement as well as mortality. This review summarises the current knowledge regarding the clinical manifestations, pathophysiology and risk factors for drug-induced psychosis in patients with PD and focuses on treatment, especially with regard to the atypical antipsychotics.

Guidelines for the use of clozapine in individuals with developmental disabilities

Clozapine is the most effective antipsychotic medication currently in use, but there has been a paucity of well-controlled research on its efficacy with people with developmental disabilities. We present a set of guidelines to ensure proper utilization of clozapine in individuals with developmental disabilities, because it can offer them therapeutic advantages similar to those observed in people with schizophrenia. We provide recommendations regarding the use of clozapine that are based on three main sources: literature and published professional practice guidelines regarding the use of clozapine in individuals who do not have developmental disabilities, the limited literature on the use of clozapine in individuals who have developmental disabilities, and our own clinical experience. The first part of the guidelines contains an overview of necessary practical knowledge regarding side effects, dose and blood level considerations, and interactions with other medications, diet and tobacco smoking. In the second part, we offer procedures for selecting individuals for clozapine therapy based on proper indications and contraindications for treatment. We also include requirements regarding informed consent, dosage and special laboratory and clinical monitoring.

Effect of anticholinergics in preventing acute deterioration in patients undergoing abrupt clozapine withdrawal

BACKGROUND

The most serious adverse effect of clozapine, agranulocytosis, was described for the first time in Finland in 1975. It caused the immediate withdrawal of clozapine from the market and immediate discontinuation of this medication in all patients. It is now known that abrupt withdrawal of clozapine may cause a rapid deterioration in psychotic symptoms.

OBJECTIVE

The aim of this retrospective study was to investigate the effect of abrupt clozapine withdrawal on psychiatric patients, and to examine whether anticholinergic drugs are effective in preventing acute deterioration.

MATERIALS AND METHODS

We reviewed the hospital case records from Pitkäniemi Psychiatric Hospital, Tampere, Finland, of the 28 patients with schizophrenia who had been receiving clozapine and from whom it was abruptly withdrawn due to the withdrawal of the drug from the market in the summer of 1975. We assessed the incidence of deterioration and whether or not patients in whom this occurred were receiving anticholinergic drugs.

RESULTS

We found a rapid deterioration after clozapine withdrawal in almost half (46.4%; n = 13) of the patients. Patients receiving anticholinergic drugs (such as antiparkinsonians, tricyclic antidepressants and antipsychotics with anticholinergic properties) were significantly less likely to deteriorate than those not receiving these drugs (21.4% vs 71.4%, p = 0.008). The condition of the patients who deteriorated was poor for up to 1 month after discontinuation, but had improved slightly by the end of 1975.

CONCLUSION

Anticholinergic medication should be considered for preventing possible symptom deterioration when clozapine is abruptly discontinued.

Risperidone Withdrawal-Related Respiratory Dyskinesia

Risperidone is a frequently used member of a new class of atypical antipsychotics-the serotonin-dopamine antagonists (SDAs)-due to its comparatively high efficacy and low D2/5HT2 binding ratio, which results in a low incidence of extrapyramidal side effects including tardive dyskinesia (TD). The authors present an elderly patient with mixed dementia who developed TD at multiple sites, (including respiratory dyskinesia [RD], limb dyskinesia, and orofacial dyskinesia) following abrupt withdrawal of risperidone therapy. RD is not a rare condition, but is often misdiagnosed and is potentially lethal. Therefore, clinicians should pay close attention to possible onset of RD in patients with multiple risk factors for TD, even when SDA therapy is used. If RD is suspected, assessment should include spirography combined with fibroscopy for examination of irregularities in the rate, rhythm, and depth of respiration.

Neuroleptic malignant syndrome and clozapine withdrawal at the same time?

The authors report a case of a patient, who in a few days after an abrupt discontinuation of clozapine and haloperidol developed agitated and confused state resembling neuroleptic malignant syndrome (NMS) and clozapine withdrawal symptoms at the same time. Data obtained from family members led to gradual reintroduction of clozapine and to subsequent recovery. The case illustrates the importance for clinicians to be familiar with the variety of discontinuation symptoms, so they can recognize them and offer effective treatment.

Clozapine Withdrawal Catatonia Associated With Cholinergic and Serotonergic Rebound Hyperactivity

Catatonia as a clozapine withdrawal syndrome has not been well documented. There is only 1 case of excited catatonia described with the diagnosis made according to strict criteria. The authors report a patient who developed a catatonic stuporous state following abrupt discontinuation of clozapine, associated with features of cholinergic and serotonergic hyperactivity. The catatonic state resolved within 1 week with reinstatement of clozapine. It is suggested that serotonergic hyperactivity was involved, contributed by cholinergic rebound, in the pathogenesis of this patient's clozapine withdrawal catatonic syndrome.

Update on Psychotropic Medication Use in Renal Disease

Renal failure is a common medical condition, and many patients have comorbid psychiatric disorders. In this review, which is intended as a resource for consultation psychiatrists, the authors discuss pharmacokinetic considerations and provide information about the use of individual psychotropic medications in patients with renal disease. Most psychotropic medications are fat soluble, easily pass the blood-brain barrier, are not dialyzable, are metabolized primarily by the liver, and are excreted mainly in bile. Consequently, the majority of these drugs can be safely used with the end-stage renal disease population.

Clozapine treatment attenuated somatic and affective signs of nicotine and amphetamine withdrawal in subsets of rats exhibiting hyposensitivity to the initial effects of clozapine

BACKGROUND

Based on the phenomenologic similarity between symptoms of drug withdrawal and the negative symptoms of schizophrenia (e.g., anhedonia), we hypothesized that treatment with clozapine may be effective against nicotine and amphetamine withdrawal.

METHODS

A rate-independent discrete-trial threshold procedure was used to assess brain stimulation reward in rats prepared with electrodes in the lateral hypothalamus. Somatic signs of nicotine withdrawal were also assessed.

RESULTS

Clozapine administration (.75 or 1.5 mg/kg) during nicotine or amphetamine withdrawal did not affect the threshold elevations associated with drug withdrawal. The.75 mg/kg clozapine dose reversed the increased number of somatic signs of nicotine withdrawal. Ten days of clozapine treatment (3 mg/kg/b.i.d.) before exposure to nicotine prevented the threshold elevations in a subset of rats and the increases in somatic signs in all subjects. Fourteen-day pretreatment with clozapine (6 mg/kg/day) decreased the duration of amphetamine withdrawal.

CONCLUSIONS

Correlational analyses indicated that the ability of clozapine to prevent the affective aspects of drug withdrawal depended on low sensitivity to acute clozapine under baseline conditions. The results are consistent with the clinical situation where clozapine is partially effective against the negative symptoms of schizophrenia and more effective in some individuals than others. These results indicate that lack of sensitivity to the initial negative effects of clozapine may predict its a subsequent therapeutic response. Finally, the data suggest that there may be commonalities in the neurosubstrates mediating affective aspects of drug withdrawal and the negative symptoms of schizophrenia.

Serum antimuscarinic activity during clozapine treatment

This study attempts: (1) to verify that serum antimuscarinic activity is related to clozapine dose, and more importantly to clozapine plasma concentrations; (2) to explore whether norclozapine has serum antimuscarinic activity; (3) to explore whether antimuscarinic activity is related to clozapine side effects; and (4) to compare the serum antimuscarinic activities of clozapine with those of antiparkinsonian drugs and other antipsychotics. In 39 patients participating in a double-blind clozapine study, the [3H]QNB assay was used to measure serum antimuscarinic activity: (1) on baseline medications; (2) after a 4-week haloperidol trial; (3) after a 16-week clozapine trial of either 100, 300, or 600 mg/d; and (4) after 1 or 2 consecutive 16-week clozapine trials with remaining doses in nonresponders. Clozapine levels predicted serum antimuscarinic activity better than clozapine dose. At the end of the 1st clozapine trial, the correlation with the levels explained 69% of the variance of serum antimuscarinic activity (r = 0.83, P < 0.001, N = 34). Clozapine levels were good predictors of serum antimuscarinic activity only in patients taking 300 or 600 mg/d. After correcting for clozapine levels, the within-subject correlation between norclozapine levels and serum antimuscarinic activity was relatively high and significant (r = 0.54, F = 26.7, df = 1.65, P < 0.001). Constipation was significantly associated with higher serum antimuscarinic activity during the 1st clozapine trial. Clozapine was associated with clearly higher antimuscarinic activity than other antipsychotics or low doses of antiparkinsonians. In vitro studies and new clinical studies are needed to verify whether norclozapine may significantly contribute to antimuscarinic activity during clozapine treatment.

Clinical experience with the management of schizophrenia in the general hospital

On the basis of experience with 74 psychiatric consultations involving patients with schizophrenia admitted to a general hospital medical or surgical ward over a 17-month period (3% of the psychiatric consultations during that period), the authors identified 10 types of problems leading to requests for consultation. The authors used these categories to organize recommendations for management of patients with schizophrenia in the general medical hospital. In addition to conducting conventional consultations, the consultation psychiatrist in such cases often has a role in educating hospital staff about schizophrenia and in serving as a physician for the mentally ill.

Clozapine withdrawal symptoms in a Parkinson's disease patient

Abrupt clozapine withdrawal can cause rebound psychosis and severe somatic symptoms in psychiatric patients. We report on the case of an advanced Parkinson's disease patient who developed myoclonus, tremor, rigidity, hyperreflexia, and stupor after abrupt clozapine withdrawal. The patient's symptoms resolved with treatment with cyproheptadine. This clinical picture suggests serotonergic rebound as an explanation for the patient's symptoms, although other pharmacological mechanisms are possible. Clozapine should be gradually withdrawn over a period of 1 to 2 weeks when possible, and abruptly discontinued only when necessary.

The role of atypical antipsychotics in the treatment of delirium

Delirium exemplifies the interface between medicine and psychiatry. It is generally characterized by acute disturbances of consciousness, cognition, and perception that are precipitated by an underlying medical condition. The gold standard of psychiatric treatment is to treat the underlying medical cause and use high-potency antipsychotics to treat the clinical manifestations of delirium. In the early 1990s, a new generation of novel antipsychotics was developed. Their mechanism of action, preferential serotonergic (5HT(2a)) blockade, results in a markedly lower rate of extrapyramidal side effects, an advantage over the typical, older antipsychotic medications. These agents have been shown to be effective and well tolerated in common psychotic disorders (e.g., schizophrenia or bipolar disorder), but few studies have evaluated them in the treatment of delirium. This paper reviews the pertinent literature and summarizes tentative guidelines for novel antipsychotic use in delirium.

Dosing and switching strategies for quetiapine fumarate

BACKGROUND

The atypical antipsychotic agent quetiapine fumarate has demonstrated efficacy and tolerability in clinical trials in patients with chronic or subchronic exacerbations of schizophrenic symptoms.

OBJECTIVE

This review summarizes clinical trial data and other practical information regarding the initiation and routine administration of quetiapine. Appropriate strategies for switching from other antipsychotic agents to quetiapine are also discussed.

RESULTS

Quetiapine is an appropriate initial treatment for psychotic disturbances in patients with schizophrenia of any stage and for those in whom a therapeutic switch is indicated for clinical reasons, such as inability to tolerate the side effects of treatment. Titration to 400 mg/d is recommended using the following schedule, administered BID in divided doses: day 1, 50 mg; day 2, 100 mg: day 3, 200 mg; day 4, 300 mg; and day 5, 400 mg. In patients who respond to quetiapine, therapy should be continued at the optimal dose that maintains remission, within the range of 150 to 750 mg/d. When a change in therapy is indicated, several strategies for switching from one antipsychotic agent to another may be applied to switching to quetiapine. Whereas studies have shown that an abrupt switch to or withdrawal from quetiapine does not produce significant clinical consequences, in practice the switch should be carefully individualized to minimize the potential for psychotic relapse or development of withdrawal symptoms.

CONCLUSIONS

Quetiapine has antipsychotic effects and good tolerability at doses from 150 to 750 mg/d. Patients can be switched to quetiapine and their treatment individualized to achieve the optimal therapeutic effect with a minimum of dose-limiting side effects. There are several strategies for switching to quetiapine from another antipsychotic agent that do not appear to cause significant exacerbation of psychosis or withdrawal reactions.