Agranulocytosis during clozapine therapy

Alternative Routes of Administration of Clozapine

Clozapine is the only antipsychotic with proven effectiveness in treatment-resistant schizophrenia. It is usually administered using commercially available oral tablets, but not all patients are willing or able to take medicines in this way. Orodispersible clozapine tablets are available from several manufacturers and may be useful where swallowing solid dosage forms is difficult, or as an aid to observe compliance. Liquid formulations of clozapine can be prepared extemporaneously or purchased commercially, but most preparations are suspensions (clozapine is poorly soluble) and patients may find them unpalatable. The administration of clozapine (suspension or crushed tablets) via enteral feeding tubes (predominantly nasogastric) has been reported both in medically unwell patients and in patients refusing clozapine. Enteral administration is likely to be superseded by intramuscular clozapine, which has recently been re-introduced and is being widely used in some countries. Successful use of this formulation in enforced treatment strategies has been described by several authors with good long-term outcomes when switched to oral treatment. Intramuscular clozapine has also been used in physically ill patients who are unable to take any form of enteral medication. Other methods of delivery (transdermal, nasal) are not yet commercially available, but offer promise of further treatment options for this group of seriously ill patients.

Clinical Experience With Intramuscular Clozapine

Clozapine is the most effective antipsychotic for patients with treatment-refractory schizophrenia, but many refuse to accept oral clozapine therapy. Intramuscular (IM) clozapine represents a convenient alternative for their treatment. The aim of this review is to summarize studies investigating IM clozapine administration. When initially developed, clozapine was also provided as an IM formulation, but the manufacturer later discontinued its production. Recently, IM clozapine became again available as an unlicensed product distributed by the Dutch company Apotheek A15. The use of IM clozapine has been reported in older studies on clozapine's adverse effects. It has also been described in detail in 5 more recent and generally smaller (n = 7 - 59) retrospective studies in patients refusing to take oral clozapine. In addition, its administration has been noted in 5 case reports. IM clozapine has been used at approximately ½ of the dose of oral clozapine due to pharmacokinetic considerations. It has been used in doses of up to 500 mg per day and for up to 99 days of treatment. The majority of patients (between 60 and 100%) were successfully transitioned to oral clozapine within a few days of IM treatment, and improvement in their condition was sustained during the long-term follow-up. Side effects of IM clozapine were similar to those of oral clozapine, but its sedative and cardiovascular effects (hypotension and tachycardia) had faster onset following IM administration. After long-term use, clozapine injections lead to local swelling and to the formation of painful nodules in some patients. In summary, IM clozapine may facilitate successful transition to oral clozapine in most patients, and it definitely represents a valuable tool for addressing refusal of oral clozapine in patients with treatment-refractory schizophrenia. More studies, especially focused on its safety, are, however, needed to better understand the limitations of this novel treatment approach.

The prevalence of agranulocytosis and related death in clozapine-treated patients: a comprehensive meta-analysis of observational studies

BACKGROUND

Clozapine treatment increases the risk of agranulocytosis, but findings on the epidemiology of agranulocytosis have been inconsistent. This meta-analysis examined the prevalence of agranulocytosis and related death in clozapine-treated patients.

METHODS

A literature search in the international (PubMed, PsycINFO, and EMBASE) and Chinese (WanFang, Chinese National Knowledge Infrastructure, and Sinomed) databases was conducted. Prevalence estimates of agranulocytosis and related death in clozapine-treated patients were synthesized with the Comprehensive Meta-Analysis program using the random-effects model.

RESULTS

Thirty-six studies with 260 948 clozapine-treated patients published between 1984 and 2018 were included in the meta-analysis. The overall prevalence of agranulocytosis and death caused by agranulocytosis were 0.4% (95% CI 0.3-0.6%) and 0.05% (95% CI 0.03-0.09%), respectively. The prevalence of agranulocytosis was moderated by sample size, study quality, year of publication, and that of data collection.

CONCLUSIONS

The prevalence of clozapine-associated agranulocytosis is low. Agranulocytosis-related death appears rare.

A quantitative analysis of antipsychotic prescribing trends for the treatment of schizophrenia in England and Wales

Objective

This study aims to assess the current antipsychotic prescribing trends for the treatment of schizophrenia and to compare them with available guidelines and research evidence.

Design

An observational retrospective quantitative analysis.

Setting

Data were collected from the prescribing cost analysis for the period between 2007 and 2014, including all drugs from the British National Formulary 4.2.1 and 4.2.2. Prescriptions were included from primary and secondary healthcare settings in England and Wales.

Participants

None.

Main outcome measures

Defined daily doses of antipsychotics were used to compare popularity of individual drugs and classes of antipsychotics.

Results

There is a consistent increase in the proportion of atypical antipsychotics prescribed, compared to typical antipsychotics, between 2007 and 2014, with atypicals accounting for 79.9% of total antipsychotics prescribed in 2014.

Conclusion

The consistent popularity of atypical antipsychotics is not concordant with the current National Institute for Health and Care Excellence guidelines for the treatment of schizophrenia or the most recent research evidence.

Clozapine linked to nanocapsules minimizes tissue and oxidative damage to biomolecules lipids, proteins and DNA in brain of rats Wistar

Clozapine, atypical antipsychotic, can change oxidative stress parameters. It is known that reactive species, in excess, can have a crucial role in the etiology of diseases, as well as, can potentiating adverse effects induce by drugs. The nanocapsules have attracted attention as carriers of several drugs, with consequent reduction of adverse effects. This study aimed to evaluate histopathology and oxidative damage of biomolecules lipids, proteins and DNA in the brain of Wistar rats after treatment with nanocapsules containing clozapine. The study consisted of eight groups of male Wistar rats (n = 6): saline (SAL), free clozapine (CZP) (25 mg/Kg i.p.), blank uncoated nanocapsules (BNC), clozapine-loaded uncoated nanocapsules (CNC) (25 mg/Kg i.p.), blank chitosan-coated nanocapsules (BCSN), clozapine-loaded chitosan-coated nanocapsules (CCSN) (25 mg/Kg i.p.), blank polyethyleneglycol-coated nanocapsules (BPEGN), clozapine-loaded polyethyleneglycol-coated nanocapsules (CPEGN) (25 mg/Kg i.p.). The animals received the formulation once a day for seven consecutive days and euthanized in the eighth day. After euthanasia, the brain was collected and homogenate was processed for further analysis. The histopathology showed less brain tissue damage in nanocapsules-treated groups. The lipid peroxidation and carbonylation of proteins showed a significant increase (p < 0.05) induced by CZP. CNC and CPEGN groups obtained a reduction membrane of lipids damage and nanocapsules-treated groups showed significant improvement protein damage. CZP was able to induce genetic oxidative damage, while the nanocapsules causing less damage to DNA. The findings show that different coatings can act protecting target tissues decreasing oxidative damage, suggesting that the drug when linked to different nanocapsules is able to mitigate the harmful effects of clozapine.

A gene expression and systems pathway analysis of the effects of clozapine compared to haloperidol in the mouse brain implicates susceptibility genes for schizophrenia

Clozapine has markedly superior clinical properties compared to other antipsychotic drugs but the side effects of agranulocytosis, weight gain and diabetes limit its use. The reason why clozapine is more effective is not well understood. We studied messenger RNA (mRNA) gene expression in the mouse brain to identify pathways changed by clozapine compared to those changed by haloperidol so that we could identify which changes were specific to clozapine. Data interpretation was performed using an over-representation analysis (ORA) of gene ontology (GO), pathways and gene-by-gene differences. Clozapine significantly changed gene expression in pathways related to neuronal growth and differentiation to a greater extent than haloperidol; including the microtubule-associated protein kinase (MAPK) signalling and GO terms related to axonogenesis and neuroblast proliferation. Several genes implicated genetically or functionally in schizophrenia such as frizzled homolog 3 (FZD3), U2AF homology motif kinase 1 (UHMK1), pericentriolar material 1 (PCM1) and brain-derived neurotrophic factor (BDNF) were changed by clozapine but not by haloperidol. Furthermore, when compared to untreated controls clozapine specifically regulated transcripts related to the glutamate system, microtubule function, presynaptic proteins and pathways associated with synaptic transmission such as clathrin cage assembly. Compared to untreated controls haloperidol modulated expression of neurotoxic and apoptotic responses such as NF-kappa B and caspase pathways, whilst clozapine did not. Pathways involving lipid and carbohydrate metabolism and appetite regulation were also more affected by clozapine than by haloperidol.

Serum concentrations of clozapine and norclozapine in the prediction of relapse of patients with schizophrenia

Schizophrenic outpatients (n=102) whose condition had stabilized with clozapine (CLZ) therapy and were being maintained on CLZ were followed for 1 year. Clinical status and concentrations of serum clozapine (CLZ) and its metabolite norclozapine (NCLZ) were evaluated periodically or when relapse occurred. Relapse was defined as a significant exacerbation of psychotic symptoms or hospitalization. Thirty-three patients relapsed and 69 did not. Relapse patients displayed significantly lower serum concentrations of CLZ and a sum of CLZ and NCLZ at endpoint than non-relapses (CLZ: 162 ng/ml vs. 237 ng/ml, p<0.001; CLZ+NCLZ: 225 ng/ml vs. 301 ng/ml, p<0.001). When all subjects were pooled together, a significant inverse correlation was observed between percent increase in the total score on the Brief Psychiatric Rating Scale (BPRS) from baseline and serum levels of CLZ alone (r=0.404, p<0.001) and the sum of CLZ and NCLZ (r=0.364, p<0.001). Relapses and non-relapses were well separated by a threshold CLZ serum concentration of 200 ng/ml with a sensitivity of 73% and a specificity of 80%. The threshold value represented about a 40% lower serum CLZ level than concentration achieved in acute treatment. Survival analysis showed a similarity of the relapse risk over time defined by the CLZ serum threshold and by symptomatic criteria. These results suggest that effective relapse prevention may require maintenance of patients at CLZ serum concentrations above 200 ng/ml and above 60% of the acute-phase level during long-term maintenance treatment of schizophrenia.

A Case Study: Treatment of Refractory Schizoaffective Disorder with Aripiprazole

Objective:

To report the use of aripiprazole in the treatment of refractory schizoaffective disorder.

Case Summary:

A 42-year-old African American male with a 10-year history of schizoaffective disorder decompensated while being treated with haloperidol decanoate 200 mg intramuscularly per month and valproic acid 500 mg twice daily. Upon admission, his Global Assessment of Function scale (GAF) score was 10 and his Mini-Mental State Examination (MMSE) score was 2. He was treated with an initial injection of haloperidol decanoate 100 mg and, thereafter, with haloperidol 5 mg orally twice a day. He remained refractory to haloperidol and, on day 14, chlorpromazine 150 mg/day was added. The patient continued to show no response. On day 20, oral aripiprazole 15 mg was substituted for haloperidol and chlorpromazine. Forty-eight hours later, the GAF score was 30 and the MMSE score was 18. Ninety-six hours after receiving aripiprazole, the GAF and MMSE scores were 40 and 26, respectively.

Discussion:

Aripiprazole has been approved for the treatment of schizophrenia and bipolar disorder; however, it has not been approved for treatment of schizoaffective disorder. Aripiprazole is a novel drug representing a new class of agents used for the treatment of psychosis. Aripiprazole is a partial agonist at the dopamine D2 and serotonin 5-HT1A receptors, but an antagonist at the serotonin 5-HT2A receptors.

Conclusions:

Aripiprazole may be useful in treatment of refractory schizoaffective disorder.

Atypicality of atypical antipsychotics

OBJECTIVE

To review the current definition of atypicality, discuss the unique features of each atypical antipsychotic, and determine whether the available drugs in this class really meet the classical definition of atypicality.

DATA SOURCES

A PubMed search was conducted to identify literature on the subject of this review, supported by additional articles based on the author's clinical knowledge and experience.

STUDY SELECTION AND DATA EXTRACTION

Relevant references were extracted and summarized in order to meet the objective of the article.

DATA SYNTHESIS

Atypical antipsychotics are considered a major advance over conventional antipsychotics, primarily because they offer effective treatment alternatives that are relatively free of extrapyramidal symptoms. In fact, the term atypicality was originally used to describe antipsychotic agents with a minimal risk of causing extrapyramidal symptoms. However, over the years the definition has been modified such that there is currently no consensus on a true definition of atypicality for these agents. Each of the atypical antipsychotics (clozapine, risperidone, olanzapine, quetiapine, ziprasidone, and aripiprazole) commercially available in the United States is unique in terms of its pharmacologic profile, differing with respect to receptor-binding affinity, mechanism of action, and adverse events. Of the available atypical antipsychotics, clozapine and quetiapine have shown the lowest propensity to cause extrapyramidal symptoms. Although the risk of extra-pyramidal symptoms is lower with risperidone and olanzapine than with conventional antipsychotics, risk increases with dose escalation. Data for ziprasidone indicate that the risk of extrapyramidal symptoms may be similar to that of risperidone and olanzapine. There is a concern of akathisia with aripiprazole; however, more experience with this agent is needed before definitive conclusions are made.

CONCLUSION

If the definition of "atypical" antipsychotic is considered to be freedom from extrapyramidal symptoms, then, based on a comprehensive review of available data and clinical experience, clozapine and quetiapine appear to be the only true atypicals.

Effects of clozapine on sleep in bipolar and schizoaffective disorders

OBJECTIVE

Sleep disturbances are strongly associated with mood disorders, although the majority of data have been obtained in patients with major depressive disorder. Studies reporting results in bipolar disorder are few, and results have not been consistent. Clozapine is a prototype of atypical antipsychotics, which is effective in improving symptoms of manic episodes in patients with bipolar disorder, or schizoaffective disorder, bipolar type and has been shown to influence sleep in other psychiatric disorders. The present study evaluated the sleep effects of clozapine in bipolar and schizoaffective disorders.

METHODS

Participants were 11 women and 4 men (range:28-53 years of age, mean 40.9+/-8.6 years), all with a history of mania by DSM-IV criteria for either bipolar I disorder or schizoaffective disorder, bipolar type. They participated in a sleep study at baseline and again after 6 months initiation of clozapine add-on therapy.

RESULTS

Sleep latency was longer on clozapine and the number of awakenings were increased, whereas time in bed (TIB) and total sleep period (TSP) were increased (range: F=6.2-17.9; df=l,12; p<0.05). Although none of the individual sleep stage showed significant treatment changes, both Stage 2 and slow-wave sleep were increased and Stage 2 decreased on clozapine. Subjective sleep measures improved on clozapine with a small but significant improvement in how rested patients felt upon awakening (t=-2.1; df=26; p<0.05).

CONCLUSION

Clozapine prolonged sleep latency, improved restedness, and increased total sleep time. Although lack of a control group limits interpretation of these results, they are in general agreement with studies in other psychiatric populations, and support the view that clozapine is primarily a NREM sleep enhancer. The improvement in restedness may be of positive clinical consequence.

Clozapine maintenance therapy in schizophrenia

Long-term pharmacotherapy with antipsychotic agents is an important aspect of the management of schizophrenia. In patients responsive to the chosen treatment, maintenance therapy is usually conducted by halving the drug dose that has proven effective during the acute phase. This strategy is suitable for maintaining remission; moreover, it can improve the patients' quality of life. Records from over 1000 patients treated with clozapine during the past 22 years were examined; 782 of these patients were diagnosed with schizophrenia according to the Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition-Text Revision (DSM-IV-TR) criteria (with the modification in early years). From this group, 181 patients were treated with clozapine for at least a year. The mean duration of long-term maintenance treatment with clozapine was 12.2+/-4.25 years (range: from 14.5 months to 18 years). Clozapine was administered in a daily dose of 50-200 mg (mean: 71.5+/-14.12 mg). In 76 schizophrenics, treatment was initiated with clozapine, whereas 105 patients were switched over from other treatments after their failure. The control group comprised 152 patients on long-term maintenance therapy with haloperidol. Clozapine administered for long-term maintenance therapy was effective both in paranoid and in catatonic schizophrenia. It also accomplished good results in patients with disorganized or residual schizophrenia, as well as in individuals with schizoaffective psychosis. Relapse rate was similar to that observed in the haloperidol group; however, patient compliance, side-effect profile, and therapeutic efficacy were all superior in the clozapine group. Long-term maintenance therapy with clozapine is successful. Compliance is good; schizophrenic patients are willing to take this atypical antipsychotic for years on end. Clozapine treatment is associated with a low relapse rate and a favorable safety profile.