Dose dependent stuttering with clozapine: a case report

Overcoming clozapine's adverse events: a narrative review of systematic reviews and meta-analyses

INTRODUCTION

Clozapine is the gold standard treatment for treatment-resistant schizophrenia, however adverse events remain a clinical challenge.

AREAS COVERED

This review presents a narrative synthesis of systematic reviews and meta-analyses that have reported the onset, incidence, prevalence, and management of clozapine's adverse events. We conducted a systematic literature search using PubMed, Embase, PsycINFO, OvidMEDLINE, CINAHL, and the Cochrane Database of Systematic Reviews from inception to April 2024.

EXPERT OPINION

Effective management of clozapine's adverse events necessitates multi-faceted, individualized, and shared-decision strategies. Despite a lack of high-quality systematic evidence, expert inter-disciplinary solutions are provided to help address a critical need for clinical guidance. This 35-year update offers an evidence-based framework to assist clinicians, patients, and caregivers navigate the adverse events associated with clozapine therapy.

Drug-induced stuttering: A comprehensive literature review

Drug-induced stuttering (DIS) is a type of neurogenic stuttering (NS). Although DIS has not been reported as frequently as other cases of NS in the literature, it is not a negligible adverse drug reaction (ADR) which can significantly affect the quality of life if not treated. This literature review aims to evaluate the epidemiological and clinical characteristics of DIS and suggests some pathophysiological mechanisms for this ADR. Relevant English-language reports in Google Scholar, PubMed, Web of Science, and Scopus were identified and assessed without time restriction. Finally, a total of 62 reports were included. Twenty-seven drugs caused 86 episodes of stuttering in 82 cases. The most episodes of DIS were related to antipsychotic drugs (57%), mostly including clozapine, followed by central nervous system agents (11.6%) and anticonvulsant drugs (9.3%). The majority of the cases were male and between the ages of 31 and 40 years. Repetitions were the most frequent core manifestations of DIS. In 55.8% of the episodes of DIS, the offending drug was withdrawn to manage stuttering, which resulted in significant improvement or complete relief of stuttering in all cases. Based on the suggested pathophysiological mechanisms for developmental stuttering and neurotransmitters dysfunctions involved in speech dysfluency, it seems that the abnormalities of several neurotransmitters, especially dopamine and glutamate, in different circuits and areas of the brain, including cortico-basal ganglia-thalamocortical loop and white matter fiber tracts, may be engaged in the pathogenesis of DIS.

Drug induced stuttering: pharmacovigilance data

Background: Stuttering is a speech disorder characterized by poor fluency of speech despite the speech production organs being normal. Numerous factors contribute to stuttering, and it may also be an iatrogenic effect of certain drugs. The aim of this study was to investigate the association between stuttering and drug exposure.Research design and methods: We investigated the association between drugs and stuttering. We analyzed reports in the World Health Organization global individual case safety reports database (Vigibase) up to 31 May 2020 with the MedDRA lower level terms 'stutter' and 'stuttering.' The association between a drug and the occurrence of the adverse drug reaction was estimated by disproportionality analysis. Reporting odds ratios (ROR) were calculated with 95% confidence intervals.Results: In total, 724 notifications were identified using the MedDRA terms selected. The main drugs implicated were methylphenidate (ROR = 19.58; 95% CI: 13.3-28.8), topiramate (ROR = 12.5; 95% CI: 7.1-22.1), olanzapine (ROR = 12; 95% CI: 8-17.9) and golimumab (ROR = 10.2; 95% CI: 5.5-19.1).Conclusions: When stuttering occurs in a patient treated by drugs affecting neurotransmission, a drug-induced origin of the stutter should be considered.

Clozapine-Induced Microseizures, Orofacial Dyskinesia, and Speech Dysfluency in an Adolescent with Treatment Resistant Early Onset Schizophrenia on Concurrent Lithium Therapy

Clozapine is an atypical antipsychotic used in the treatment of refractory schizophrenia. It has a well-known side effect profile, including agranulocytosis, decreased seizure threshold, and tardive dyskinesia. In addition, numerous case reports have described clozapine-induced stuttering in adults. However, there has been only one previous case report describing it in the adolescent population. In addition, concurrent lithium therapy has been shown to enhance the neurotoxic effects of antipsychotics and lower the seizure threshold. Here, we report on the development of clozapine-induced microseizures, orofacial dyskinesia, and stuttering in a 17-year-old adolescent male with treatment of refractory early onset schizophrenia on clozapine and concurrent lithium therapy. The patient's symptoms of schizophrenia responded well to the clozapine regimen. However, with the escalating dose of clozapine, the patient developed speech dysfluency in the form of stuttering and perioral twitching. An electroencephalogram confirmed seizure activity. Due to similarities with tardive dyskinesia, symptoms of microseizures induced by atypical antipsychotics may not be accurately diagnosed. A multidisciplinary treatment of speech dysfluency is of particular importance in the adolescent schizophrenic patients, who are expected to have longer duration of lifetime exposure to antipsychotics and in whom peer group interaction is crucial for normal personal and social development.

Clozapine for treatment of aggression in non-psychotic adolescents

Use of Second Generation Antipsychotics (SGAs) in children and adolescents has grown more significantly in recent years. Clozapine has shown good results for the treatment of aggression in adult population but no case has been reported about the use of clozapine for treatment of aggression in non-psychotic adolescents. We present cases of 2 adolescents in which clozapine was used primarily to treat their aggressive behavior and suicidal ideation.

Clozapine-induced stuttering: an estimate of prevalence in the west of Ireland

OBJECTIVES

Clozapine is the most effective treatment available for treatment-resistant schizophrenia; however, it is also associated with a large array of adverse effects that limits its tolerability. A number of previous case reports have noted an association between clozapine and stuttering, however the rate of this possible adverse effect is yet to be established.

METHODS

In this paper, we present six cases of patients treated with clozapine who developed stuttering.

RESULTS

Clozapine was associated with stuttering in 0.92% of individuals treated with clozapine in the region. Clozapine-induced stuttering was associated with an increase in treatment dose or with dose titration at initiation of clozapine in five individuals, with dose reduction or slower dose titration associated with a cessation of stuttering in these cases.

CONCLUSIONS

This is the largest case series to date examining clozapine-induced stuttering and indicates that clozapine-induced stuttering is a relatively common adverse effect that can be managed by a slower titration of clozapine dosage or a modest reduction in dose in most cases.