Clozapine-induced myoclonus: a case report and review of the literature

Electric Shock Sensation and Recurrent Falls as a Side Effect of Clozapine Therapy: A Case Report

Clozapine is an atypical antipsychotic that acts by blocking mainly dopamine 4 receptors. It is usually prescribed for treatment-resistant schizophrenia as well as treatment-resistant bipolar disorder. Clozapine has a wide profile of side effects that result from blocking different receptors all over the body. A 42-year-old Middle Eastern female is known to have suffered from schizoaffective disorder for many years and had frequent relapses despite compliance with treatment. She was commenced on Clozapine; the patient started complaining of an electric shock sensation throughout her body that resulted in recurrent falls with bilateral leg fractures. She was started on sodium valproate to exclude the possibility of seizure activity but the electric shock sensation did not subside. The decision was made to switch her to aripiprazole and gradually taper down and stop Clozapine which improved her symptoms. Careful monitoring of patients who receive Clozapine is recommended especially during the tapering phase due to the risky adverse events it can bring about. It is essential to understand the side effects in order to tackle them as soon as they arise.

Low-dose clozapine-related seizure: A case report and literature review

BACKGROUND

Treatment-resistant schizophrenia is a severe form of schizophrenia characterized by poor response to at least two antipsychotic drugs and is typically treated with clozapine. However, clozapine lowers the epileptic threshold, leading to seizures, which are severe side effects of antipsychotics that result in multiple complications. Clozapine-related seizures are generally considered to be dose-dependent and especially rare in the low-dose (150-300 mg/d) clozapine treated population. Due to clinical rarity, little is known about its clinical characteristics and treatment.

CASE SUMMARY

A 62-year-old Chinese man with a 40-year history of treatment-resistant schizophrenia presented to the Emergency Department with symptoms of myoclonus, consciousness disturbance and vomiting after taking 125 mg clozapine. Upon admission, the patient had a suddenly generalized tonic-clonic seizure lasting for about half a minute with persistent disturbance of consciousness, fever, cough and bloody sputum, which was considered to be low-dose clozapine-related seizure. After antiepileptic and multiple anti-infection treatments, the patient was discharged without epileptic or psychotic symptoms.

CONCLUSION

Our aim is to highlight the early prevention and optimal treatment of clozapine-related seizure through case analysis and literature review.

Risk factors for clozapine-induced central nervous system abnormalities in Japanese patients with treatment-resistant schizophrenia

The purpose of this study was to assess the risk factors for clozapine-induced central nervous system (CNS) abnormalities (i.e., electroencephalogram [EEG] abnormalities, myoclonus, and seizures). We retrospectively analyzed data from 106 patients with schizophrenia who received clozapine treatment through our hospital. A review of the EEG recordings showed that 71 of these patients (67.0 %) developed CNS abnormalities after initiating clozapine treatment. EEG abnormalities, myoclonus, and seizures occurred in 53.8 %, 38.7 %, and 8.5 % of the patients, respectively. Multivariate logistic regression analysis showed that the risk factors for clozapine-induced CNS abnormalities were concomitant lithium usage (odds ratio, 4.560; 95 % confidence interval, 1.750-11.900) and shorter illness durations before clozapine initiation (odds ratio, 0.796; 95 % confidence interval, 0.649-0.976). However, plasma clozapine levels and the usage of antiepileptics did not exhibit associations with the risks of CNS abnormalities. Clinicians should monitor their patients for incident CNS abnormalities when administering lithium in combination with clozapine regardless of plasma clozapine levels or the usage of antiepileptics. This is especially true for patients with short illness durations.

Knee Buckling (Negative Myoclonus) Associated With Clozapine: Reports on 3 Cases

BACKGROUND

Negative myoclonus is rarely seen in the clinical setting. It can be involved in some central nervous system pathologies. It has also been observed after antipsychotic treatment.

CASE REPORTS

In this article, we will present 3 cases diagnosed with negative myoclonus in a 120-bed university-affiliated hospital within the past 7 years. Based on our clinical experience, it was observed that myoclonic jerk was a rare condition that started with suddenly dose changes. Patients showed good improvement in response to dose reduction.

CONCLUSIONS

Since the number of reported cases on negative myoclonus is limited, there is still a lack of well-established consensus on the management of this disease. It can be concluded that myoclonic jerk may be dose-dependent, sudden dose changes may be effective, anticonvulsants are not effective in all cases, and treatment can be achieved by reducing the dose.

Elevated clozapine levels associated with infection: A systematic review

Clozapine is the most effective anti-psychotic medication for treatment refractory schizophrenia. A growing number of case reports have linked infection to high clozapine levels and associated adverse outcomes. We present a systematic review of published cases to clarify the relationship between infection and elevated clozapine levels. The case reports were located through PubMed and Embase. In addition, 8 new cases from two Australian states were included. Demographics, psychiatric diagnoses and medical morbidities, medications, clinical symptoms, clozapine levels, inflammatory markers and final clinical outcome were extracted. 40 cases were identified in 23 publications that demonstrated elevated clozapine levels associated with infection. Infections were commonly respiratory in origin. Adverse events, typically sedation, were associated with raised clozapine levels during infection. In many cases the signs of infection such as fever and white blood cell count were reduced. Severe adverse effects were uncommon, with one case each of seizure, myocarditis and neutropenia. The relationship between infection, clozapine levels and adverse events is complex and multi-factorial. Monitoring of clozapine levels is essential during hospitalisation for infection and consideration should be given to gradual dose reduction to minimise dose related side effects.

A Case of Resistant Schizophrenia Successfully Treated With Clozapine/Long-acting Injectable Aripiprazole Combination

BACKGROUND

Treatment-resistant schizophrenia (TRS) is a condition characterized by intense symptom severity and poor response to different antipsychotic agents. The first therapeutic option in TRS is clozapine, but often high/medium doses are not tolerated. Adding an oral antipsychotic to low doses of clozapine is a promising strategy in the management of TRS. On the contrary, there are few data on combined clozapine/long-acting injectable (LAI) medications, and none on clozapine/LAI-aripiprazole.

CASE

A 21-year-old male schizophrenic patient, resistant to several oral and LAI medications, partially improved after clozapine 300 mg/d treatment. Unfortunately, he also reported excessive sedation and an episode of myoclonus, so clozapine was reduced to 150 mg/d, but no additional benefits were observed. Subsequently, LAI-aripiprazole (first 200 mg/mo, then 400 mg/mo) was added, and the patient's conditions dramatically improved over time. After 1 year of observation, symptoms reduction was 50% or greater, without significant adverse events.

CONCLUSIONS

Clozapine use in TRS is often reduced or delayed due to the fear of serious adverse effects. Adding LAI-aripiprazole to low doses of clozapine may be a useful therapeutic option to obtain a good efficacy/tolerability balance.