Clinical observation on treatment of Tourette syndrome in Chinese children by clonidine adhesive patch

An update on the pharmacological management of Tourette syndrome and emerging treatment paradigms

INTRODUCTION

Tourette syndrome (TS) is a childhood-onset neurobehavioral disorder characterized by tics. Pharmacotherapy is advised for patients whose symptoms affect their quality of life.

AREAS COVERED

The authors review the tic phenomenology and TS diagnostic criteria. The bulk of this article focuses on pharmacotherapeutic options for treating tics. They also highlight pharmacotherapies in the research pipeline.

EXPERT OPINION

Tic treatment must be tailored to individual needs. Behavioral therapy is the first line of treatment. Most with bothersome tics need pharmacotherapy and rarely, for medication-refractory cases, surgical therapy is indicated. Alpha-2 agonists are considered in patients with mild tics, especially in those with attention deficit with or without hyperactivity. Second-generation antipsychotics like aripiprazole and tiapride may be considered for severe tics. However, prescribers should be mindful of potential side effects, especially drug-induced movement disorders. Botulinum toxin injections may be considered for focal motor tics. Topiramate can be considered when other treatments are ineffective, and its benefits outweigh the risks. The same holds true for vesicular monoamine transporter-2 inhibitors, as they are deemed to be safe and effective in real-world use and open-label trials despite not meeting primary endpoints in placebo-controlled trials. Cannabinoids may be considered in adults if the approaches above do not control tics.

Efficacy of Clonidine Adhesive Patch for Patients With Tourette Syndrome: A Randomized, Double-blind, Placebo-Controlled, Multicenter Clinical Trial

OBJECTIVE

This study aimed to explore the efficacy of the clonidine adhesive patch for participants with Tourette syndrome (TS).

METHODS

This randomized, double-blind, placebo-controlled, multicenter phase IV clinical trial included participants with TS at 20 centers between May 2012 and March 2015. Treatment efficacy at week 8 was the primary outcome. The Clinical Global Impression-Severity scale and Improvement scale were the secondary endpoints.

RESULTS

This trial included 488 participants, with 121 participants in the 2.0-mg/wk group, 119 participants in the 1.5-mg/wk group, 126 participants in the 1.0-mg/wk group, and 122 participants in the placebo group. For Yale Global Tic Severity Scale score reduction rate, compared with the placebo group (39.60 ± 25.56), those of the 2.0-mg/wk group (63.21 ± 32.60) and the 1.5-mg/wk group (68.16 ± 25.88) were statistically significantly different (all P < 0.001). For total Yale Global Tic Severity Scale score, compared with the placebo group (17.0 ± 8.03), the score for the 2.0-mg/wk group was 9.9 ± 8.36 ( P < 0.001); 1.5-mg/wk group, 9.6 ± 8.03 ( P < 0.001); and 1.0-mg/wk group, 10.5 ± 9.28 ( P < 0.001). The Clinical Global Impression-Severity scale and Improvement scale scores were statistically significantly different in the 3 clonidine (or experimental) groups compared with the placebo group (all P < 0.001).

CONCLUSIONS

Larger doses of the clonidine adhesive patch such as 1.5 and 2.0 mg/wk are effective in improving the symptoms and overall function of participants with TS.

Pharmacological treatment of Tourette's syndrome: from the past to the future

Tourette's syndrome (TS) is a neuropsychiatric disease featuring tics and vocal tics, with a prevalence of approximately 1%, including 75% of the total number of male patients. TS seriously disturbs the patients' career, education, and life and brings a serious and unbearable psychological burden to the patients themselves and their families. At present, there are no specific clinical medications recommended for treating TS. Therefore, it is necessary to select the appropriate medication for symptomatic treatment based on the doctor's personal experience and the patient's symptoms, with the main goal of relieving symptoms, thus improving the patient's social skills and psychological problems. Here we conducted a comprehensive search on PubMed to review and organize the history and current status of the development of drug therapy for TS through a timeline format. We also systematically evaluated the effects of each drug for TS treatment to summarize the current problems and new research directions and to provide some ideas for clinical treatment.

Tourette syndrome and other tic disorders of childhood

Tics are repetitive, patterned, and nonrhythmic movements or vocalizations/audible sounds that are misplaced in context. Phenomenology and characteristics of tics (e.g., premonitory urge, suppressibility) differentiate them from compulsions, stereotypies, functional tic-like behaviors, and other types of hyperkinetic movement disorders. With a prevalence of approximately 1% in school-aged boys, Tourette syndrome (TS) is considered a common childhood-onset neurodevelopmental disorder, defined by the combination of at least two motor tics and at least one phonic tic lasting more than 1 year. TS is a highly heritable disorder, with a wide spectrum of severity. In some individuals, tics can cause pain, distress, functional impairment, or stigmatization. About 90% of individuals with TS have at least one mental health comorbidity (attention-deficit/hyperactivity disorder, obsessive-compulsive disorder, anxiety/depressive disorders). These comorbidities significantly impact patients' quality of life and must therefore be screened and managed accordingly in this population. Treatment of tics is based on behavioral therapies targeting tics (habit reversal training included in the comprehensive behavioral intervention for tics, and exposure and response prevention for tics), in association with medication if needed (e.g., alpha-2-agonists, second-generation antipsychotics). Deep brain stimulation is considered an experimental option in the most severe, treatment-resistant patients. In adulthood, less than 25% of individuals still have moderate or severe tics.

Pharmacologic Treatment of Comorbid Attention-Deficit/Hyperactivity Disorder and Tourette and Tic Disorders

A complete and comprehensive medical and psychiatric evaluation is necessary to delineate tic symptoms from attention-deficit/hyperactivity disorder, and to prioritize the most problematic symptoms for intervention. Stimulants are the recommended first-line pharmacotherapy to treat attention-deficit/hyperactivity disorder symptoms in patients with tic disorders. Comprehensive behavioral intervention for tics is an effective behavioral therapy that is generally considered the first-line treatment of persistent tic disorders. α-Agonists can be added to stimulants if tics increase or be used as monotherapy to target attention-deficit/hyperactivity disorder and tics. Atomoxetine is also an excellent option to treat attention-deficit/hyperactivity disorder and tics.

Tourette Syndrome Treatment Updates: a Review and Discussion of the Current and Upcoming Literature

PURPOSE OF REVIEW

This study aims to examine the treatments currently available for Tourette syndrome (TS) and to discuss evolving therapies, spanning behavioral, pharmacologic, complementary and alternative medicine, and neuromodulation approaches.

RECENT FINDINGS

Behavioral therapies have undergone several modifications to improve accessibility, including transitioning to a virtual format which is particularly important in the current pandemic. There are several recent or ongoing pharmacologic studies that have shown promise including the selective D1 receptor antagonist ecopipam and various cannabinoid compounds. Adaptive DBS may enable the physiologic markers of tics to determine stimulation parameters and improve tic outcomes related to neuromodulation. In recent years, there has been a wealth of research across multiple treatment domains in the TS field. This review highlights exciting and new potential options for the future treatment of patients with TS.

The clinical intervention choice for pediatric tic disorder patients from a tertiary children's hospital in China: a large-scale retrospective study based on electronic medical records

Pharmacological intervention played an important role in the management of tic disorder. Large-scale prescription data for pediatric tic disorder patients in the real-world setting were scarce. The demographic and prescription data of tic disorder were extracted from the electronic medical records database of Beijing Children's Hospital from 2018 to 2020. The intervention choice for outpatient pediatric tic disorder patients was analyzed. A total of 20 417 patients were included, 28.1% (n = 5028) of them did not receive any pharmacological treatment. Over 70% were prescribed with anti-tic medication. For children less than 6 years of age, clonidine adhesive patches (CAPs) and traditional Chinese medicine (TCM) were the common choice. With the age growing, the use of antipsychotics was on the rise; 22% (n = 3389) were prescribed for at least two anti-tic medication, and the most common medication combination group was tiapride and TCM (33.7%), followed by CAP and TCM (22.1%). The clinical intervention choice for tic disorder is highly individualized. The pharmacological choice was influenced by severity, duration of symptom, age, the acceptance of parents and other factors.

Current Status, Diagnosis, and Treatment Recommendation for Tic Disorders in China

Tic disorders (TD) are a group neuropsychiatric disorders with childhood onset characterized by tics, i.e. repetitive, sudden, and involuntary movements or vocalizations; and Tourette syndrome (TS) is the most severe form of TD. Their clinical manifestations are diverse; and are often associated with various psychopathological and/or behavioral comorbidities, including attention deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), anxiety, depression, and sleep disorders. Individual severity and response to treatment are highly variable, and there are some refractory cases, which are less responsive to conventional TD treatment. TD/TS are also common in the Chinese pediatric population. To help improve the understanding of TD for pediatricians and other health professionals, and to improve its diagnosis and treatment in China, the Chinese Child Neurology Society (CCNS) has developed an Expert Consensus on Diagnosis and Treatment of TD in China, which is based on our clinical experience and the availability therapeutic avenues. It is focused on clinical diagnosis and evaluation of TD and its comorbidities, psychological and educational intervention, nonpharmacological therapy, pharmacological treatment, including traditional Chinese medicine and acupuncture, as well as prognosis in children with TD in China. A summary of the current status of TD and up-to-date diagnosis and treatment recommendations for TD in China is presented here.

Effects of 24 CYP2D6 variants found in Chinese population on the metabolism of clonidine in vitro

BACKGROUND AND OBJECTIVES

Clonidine has been clinically used to treat Tourette's syndrome for decades. There was research finding that clonidine possessed the best risk-benefit ratio, especially for patients associated with attention deficit hyperactivity disorder. CYP2D6 is a significant member of Cytochrome P450 enzymes. The genetic polymorphisms of CYP2D6 greatly affect the clinical effects of drugs even lead to side effects and medical malpractice. Our goal is to research the effect of CYP2D6 genetic polymorphism on the metabolism of clonidine and evaluate the functions of 22 CYP2D6 allelic variants in vitro, which were discovered in Chinese Han population recently.

METHODS

This study was carried out through a mature incubation system. The wild-type CYP2D6*1 and 24 variants (CYP2D6*2, CYP2D6*10 and 22 novel CYP2D6 variants) were expressed in insect cells, and the catalytic activity of all the variants were assessed by substrate clonidine. Metabolite 4-OH clonidine was accurately detected via ultra-performance liquid-chromatography tandem mass spectrometry to evaluate the effect of CYP2D6 genetic polymorphism on the clonidine.

RESULT

Among the 22 novel CYP2D6 variants, the intrinsic clearance (Vmax/Km) of 21 variants were significantly decreased (from 1.53% to 83.25%) compared to the wild-type. In particular, the following seven variants (CYP2D6* 2, CYP2D6* 10, CYP2D6* 93, CYP2D6* 95, E215K, V327 M and R497C) attract more attention, of which the intrinsic clearance decreased more than 70% compared to the wild-type. Because the variants with significantly reduced intrinsic clearance are more likely to cause adverse reactions than the variants with increased or little changed intrinsic clearance. In addition, the related pharmacokinetic parameters of CYP2D6*92 and CYP2D6*96 could not be acquired for the defect of CYP2D6 nucleotide.

CONCLUSION

We comprehensively evaluated the effect of 22 novel CYP2D6 variants on the metabolism of clonidine for the first time and hoped corresponding data provide a reference for metabolism of clonidine for further studies in vivo, and extend our understanding of the clinical drug toxicity or ineffectiveness by CYP2D6 genetic polymorphism.

Evidence-based treatment of Tourette's disorder and chronic tic disorders

Introduction: Chronic Tic Disorders and Tourette's Disorder (collectively referred to as TD) are characterized by sudden, rapid, and repetitive motor movements or vocalizations called tics. Children, adolescents, and adults with TD often experience co-occurring psychiatric symptoms and impairments in multiple domains. As a result of tics and other symptoms, patients with TD can develop negative self-views, require considerable accommodations, and experience a poor quality of life. Therefore, the efficient and effective management of TD bears considerable importance. Areas covered: This expert review evaluated the empirical support for behavioral and pharmacological interventions based on the results of randomized controlled trials (RCTs). Behavioral interventions evaluated include habit reversal training (HRT), comprehensive behavioral intervention for tics (CBIT), and exposure response prevention (ERP). Reviewed pharmacological interventions included alpha-2 agonists, antipsychotics, and anticonvulsants. Expert opinion: This review identified several efficacious behavioral and pharmacological interventions for TD. However, several gaps in the management of TD include: (1) the access/availability of behavioral interventions, (2) novel and more efficacious treatment approaches, and (3) the development of more comprehensive interventions to manage TD. In order to advance the treatment of TD, additional research is necessary to efficiently, effectively, and comprehensively develop and evaluate new treatments for patients with TD.

A case report of clonidine induced syncope: a review of central actions of an old cardiovascular drug

Background

Clonidine is an imidazoline sympatholytic, acting on both α₂-adrenergic and imidazoline receptors in the brainstem to induce antihypertensive and negative chronotropic effects in the vasculature and heart respectively.

Case presentation

A 69-year-old gentleman with hypertension presented to the emergency department after multiple syncopal episodes over the past 12 months. Electrocardiogram demonstrated sinus bradycardia with a heart rate of 42 beats per minute. It was hypothesized that the antihypertensive agent clonidine was responsible for inducing symptomatic bradycardia. Clonidine was thus gradually tapered and then discontinued over five days restoring normal sinus rhythm rates while avoiding hypertensive rebound related to sympathetic surge. His heart rate and blood pressure remained within normal limits after the clonidine taper and subsequent adjustments to his other hypertensive medications and he was discharged.

Conclusions

While clonidine has fallen out of favor for its indication as an antihypertensive, it remains a viable option for the use of opioid withdrawal, chronic pain, and smoking cessation, necessitating the appropriate clinical and pharmacological competencies for a physician to prescribe. A discussion of the clinical effects of clonidine brainstem receptor activation follows.

Treatment of Children and Adolescents with Attention Deficit Hyperactivity Disorder and/or Tourette's Disorder with Clonidine Extended Release

We aimed to assess the effectiveness and safety of clonidine extended release (ER) treatment in Korean youth with ADHD and/or Tourette's disorder. We retrospectively reviewed the medical records of 29 children and adolescents treated with clonidine ER. The effectiveness were retrospectively measured at baseline and after 4 and 12 weeks based on the Clinical Global Impression-Severity (CGI-S) and Clinical Global Impression-Improvement (CGI-I) scores. Safety was evaluated at each visit based on spontaneous reports from the subjects or from their parents/guardians. Significant decreases in the CGI-S scores for both ADHD (F=23.478, p<0.001, partial η2=0.540) and tic symptoms (F=15.137, p<0.001, partial η2=0.443) were noted over 12 weeks. The most common adverse event was somnolence (n=9, 31.0%) and life-threatening adverse effects were not observed. Our results provide preliminary evidence for the effectiveness and safety of clonidine ER.

[Efficacy of clonidine transdermal patch in treatment of moderate to severe tic disorders in children]

OBJECTIVE

To investigate the difference in the efficacy between clonidine transdermal patch and haloperidol tablets in the treatment of moderate to severe tic disorders in children.

METHODS

A total of 134 children with moderate to severe tic disorders were randomly divided into clonidine group (n=70) and haloperidol group (n=64). The clonidine and haloperidol groups were treated with clonidine transdermal patch and haloperidol tablets respectively, and the treatment lasted for 8 weeks in both groups. The Yale Global Tic Severity Scale (YGTSS) was used to evaluate the conditions of the children before and after treatment, and the adverse events during the treatment were recorded.

RESULTS

The haloperidol group had a significantly better treatment outcome than the clonidine group after one week of treatment (P<0.05); the treatment outcome showed no significant difference between the two groups after 3, 5, and 8 weeks of treatment (P>0.05). The clonidine group had significantly less reductions in the motor tics, vocal tics, and function impairment scores and total score of YGTSS than the haloperidol group after one week of treatment (P<0.05); there were no significant differences in YGTSS score reductions between the two groups after 3, 5, and 8 weeks of treatment (P>0.05). The clonidine group had a significantly lower overall incidence of adverse events than the haloperidol group (8% vs 37%; P<0.01).

CONCLUSIONS

Clonidine transdermal patch and haloperidol are both effective in the treatment of moderate to severe tic disorders in children. The clonidine transdermal patch, despite slow action, has comparable efficacy and fewer adverse effects compared with haloperidol.

Clonidine adhesive patch for the treatment of tic disorders: A systematic review and meta-analysis

OBJECTIVE

The aim of this study was to evaluate the efficacy and safety of clonidine adhesive patch for tic disorders (TDs).

METHODS

Medline, Embase, Cochrane central register of controlled trials and Chinese databases of CBM, CNKI were searched from inception to 08.2016 for randomized controlled studies (RCTs), open-label control studies of clonidine adhesive patch versus other medications or/and placebo for TDs. The cochrane Handbook for Systematic Reviews of Interventions was used to guide our study.

RESULTS

Six studies involving 1145 participants were included in this study. Among these studies, two study (N = 513 patients) used placebo as a control and four studies (N = 632 patients) used positive drug controls. The results of meta-analysis suggested that clonidine adhesive patch may be as effective as haloperidol or tiapride for TDs. Adverse events (AEs) were reported in all studies, and the most common AEs of clonidine adhesive patch were rash (8.9%), lightheadedness (8.0%), dry mouth (4.0%). The AEs of clonidine adhesive patch were slight.

CONCLUSION

These data provide moderate quality evidence that clonidine adhesive patch might be an effective and safe treatment option for TDs, and results from further trials are urgently needed to extend the evidence base.

Tics in the Pediatric Population: Pragmatic Management

BACKGROUND

Primary tic disorders, notably Tourette syndrome, are very common movement disorders in childhood. However, the management of such patients still poses great therapeutic challenges to medical professionals.

METHODS

Based on a synthesis of the available guidelines published in Europe, Canada, and the United States, coupled with more recent therapeutic developments, the authors provide a pragmatic guide to aid clinicians in deciding when and how to treat patients who have primary tic disorders.

RESULTS

After a systematic assessment of tics and common neuropsychiatric comorbidities (primarily attention-deficit hyperactivity disorder [ADHD] and obsessive-compulsive disorder [OCD]), the first step in treatment is a comprehensive psychoeducation of patients and families that addresses the protean phenomenology of tics and associated behaviors, coping mechanisms, prognosis, and treatment options. When more active intervention beyond watchful monitoring is indicated, hierarchical evaluation of treatment targets (i.e., tics vs. comorbid behavioral symptoms) is crucial. Behavioral treatments for tics are restricted to older children and are not readily available to all centers, mainly due to the paucity of well-trained therapists. Pharmacological treatments, such as antipsychotics for tics, stimulants and atomoxetine for ADHD, and α2A-agonists for children with tics plus ADHD, represent widely available and effective treatment options, but safety monitoring must be provided. Combined polypharmacological and behavioral/pharmacological approaches, as well as neuromodulation strategies, remain under-investigated in this population of patients.

CONCLUSIONS

The treatment of children with tics and Tourette syndrome is multifaceted. Multidisciplinary teams with expertise in neurology, psychiatry, psychology, and pediatrics may be helpful to address the complex needs of these children.