Efficacy and safety of tipepidine as adjunctive therapy in children with attention-deficit/hyperactivity disorder: Randomized, double-blind, placebo-controlled clinical trial

Prediction of combination effect of quinidine on the pharmacokinetics of tipepidine using a physiologically based pharmacokinetic model

Tipepidine, an antitussive drug, has been reported to have central pharmacological effects and can be expected to be safely repositioned as treatment for psychiatric disorders. Since tipepidine requires three doses per day, development of a once-daily medication would be highly beneficial. Previously, we reported that combination use with quinidine, a CYP2D6 inhibitor, prolongs the half-life of tipepidine in chimeric mice with humanised liver.In this study, to predict this combination effect in humans, a physiologically based pharmacokinetic (PBPK) model was developed, and quantitative simulation was conducted. The simulation results indicated that concomitant administration of tipepidine with quinidine increased the predicted Cmax, AUC, and t1/2 of tipepidine in the Japanese population by 3.4-, 6.6-, and 2.4-fold, respectively.Furthermore, to compare with another approach that aims to prolong the half-life, the PK profile of tipepidine administered in hypothetical extended-release form was simulated. Extended-release form was predicted to be more influenced by CYP2D6 genotype than combination with quinidine, and the predicted plasma exposure was markedly increased in poor metabolizers, potentially leading to adverse effects.In conclusion, quantitative simulation using the PBPK model suggests the feasibility of the safe repositioning of tipepidine as a once-daily medication in combination with quinidine.

A Practical, Evidence-informed Approach to Managing Stimulant-Refractory Attention Deficit Hyperactivity Disorder (ADHD)

Stimulants (methylphenidate or amphetamines) are the recommended first-line option for the pharmacological treatment of individuals with attention deficit hyperactivity disorder (ADHD). However, some patients with ADHD will not respond optimally to stimulants. Here, we discuss strategies to manage stimulant-refractory ADHD, based on the recommendations advanced in clinical guidelines, knowledge of expert practice in the field, and our own clinical recommendations, informed by a comprehensive literature search in PubMed, PsycInfo, EMBASE + EMBASE classic, OVID Medline, and Web of Science (up to 30 March 2021). We first highlight the importance of stimulant optimization as an effective strategy to increase response. We then discuss a series of factors that should be considered before using alternative pharmacological strategies for ADHD, including poor adherence, time action properties of stimulants (and wearing-off of effects), poor tolerability (that prevents the use of higher, more effective doses), excessive focus on or confounding from presence of comorbid non-ADHD symptoms, and tolerance. Finally, we consider the role of non-stimulants and combined pharmacological approaches. While the choice of medication for ADHD is still to a large extent based on a trial-and-error process, there are reasonably accepted data and guidelines to aid in clinical decision-making. It is hoped that advances in precision psychiatry in the years ahead will further guide prescribers to tailor medication choice to the specific characteristics of the patient.

Does Pregnenolone Adjunct to Risperidone Ameliorate Irritable Behavior in Adolescents With Autism Spectrum Disorder: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial?

OBJECTIVES

Pregnenolone is a neurosteroid with modulatory effects on γ-aminobutyric acid neurotransmission. Here, we aimed to evaluate the effectiveness and safety of pregnenolone add-on to risperidone in adolescents with autism spectrum disorders (ASD).

METHODS

Sixty-four ASD patients were randomly allocated to receive either pregnenolone (n = 32) or matching placebo (n = 32) in addition to risperidone. The Aberrant Behavior Checklist-Community Edition scale was used to evaluate the behavioral status of patients at baseline, week 5, and the trial end point. The change in score of irritability subscale was the primary outcome. Frequency of adverse effects due to trial medications was compared between the treatment groups.

RESULTS

Fifty-nine patients completed the trial (30 in pregnenolone and 29 in the placebo arm). Baseline characteristics of both treatment groups were similar (P > 0.05). Repeated measures analysis was suggestive of greater exhibited improvement for the pregnenolone group on irritability, stereotypy, and hyperactivity subscales of the Aberrant Behavior Checklist-Community Edition over the trial period (F = 3.84, df = 1.96, P = 0.025; F = 4.29, df = 1.39, P = 0.029; F = 6.55, df = 1.67, P = 0.004, respectively). Nonetheless, the alterations in lethargy and inappropriate speech domains scores were similar for both arms (F = 0.93, df = 1.49, P = 0.375; F = 1.10, df = 1.60, P = 0.325, respectively). There was no significant difference in frequency as well as severity of adverse effects between the 2 groups.

CONCLUSIONS

Pregnenolone adjunct to risperidone could attenuate core features associated with ASD.

Evidence-based pharmacological treatment options for ADHD in children and adolescents

Attention-deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by inattention, hyperactivity, and impulsivity, causing functional impairment. Its prevalence lies at approximately 5% in children and adolescents and at approximately 2.5% in adults. The disorder follows a multifactorial etiology and shows a high heritability. Patients show a high interindividual and intraindividual variability of symptoms, with executive deficits in several cognitive domains. Overall, ADHD is associated with high rates of psychiatric comorbidities, and insufficient treatment is linked to adverse long-term outcomes. Current clinical guidelines recommend an individualized multimodal treatment approach including psychoeducation, pharmacological interventions, and non-pharmacological interventions. Available medications include stimulants (methylphenidate, amphetamines) and non-stimulants (atomoxetine, guanfacine, clonidine). While available pharmacological treatment options for ADHD show relatively large effect sizes (in short-term trials) and overall good tolerability, there is still a need for improvement of current pharmacotherapeutic strategies and for the development of novel medications. This review summarizes available pharmacological treatment options for ADHD in children and adolescents, identifies current issues in research and evidence gaps, and provides an overview of ongoing efforts to develop new medications for the treatment of ADHD in children and adolescents by means of a systematic cross-sectional analysis of the clinical trials registry www.clinicaltrials.gov.

Resveratrol adjunct to methylphenidate improves symptoms of attention-deficit/hyperactivity disorder: a randomized, double-blinded, placebo-controlled clinical trial

Current pharmacological approaches have failed to provide complete remission for patients with Attention-Deficit/Hyperactivity Disorder (ADHD). This study aimed to evaluate the efficacy and tolerability of resveratrol (that have been shown to have antioxidative, anti-inflammatory, and anti-apoptotic effects) as an adjunct to methylphenidate in pharmacologic treatment of ADHD. This 8-week, double-blinded, placebo-controlled trial randomized 66 participants to receive either 500 mg/day resveratrol or matched placebo in addition to methylphenidate. ADHD symptoms were evaluated in the patients using the Parent and Teacher versions of ADHD-Rating Scale (ADHD-RS) at three measurement points with time intervals of 4 weeks. Furthermore, the tolerability of the treatment strategies was systematically compared. Repeated measures analysis demonstrated a significant effect for time-treatment interaction on all three subscales of the Parent ADHD-RS during the trial period (total: p = 0.015; inattention: p = 0.032; hyperactivity/impulsivity: p = 0.036). Nevertheless, the effect for time-treatment interaction was not significant for the Teacher version of ADHD-RS (total: F = 0.81, df = 1.33, p = 0.401; inattention: F = 0.57, df = 1.37, p = 0.507; hyperactivity/impulsivity: F = 0.65, df = 1.34, p = 0.466). The frequencies of complications in the treatment groups were similar. Resveratrol administration for a duration of 8 weeks improved characteristic symptoms in patients with ADHD according to their parents. Further investigations containing larger sample sizes, longer supplementation periods, and dose-response evaluations are required to replicate these findings in ADHD children more confidently.

Efficacy and safety of tipepidine as adjunctive therapy in major depressive disorder: A randomized, double-blind, placebo-controlled clinical trial

AIM

Tipepidine, a synthetic, non-opioid expectorant, has been shown to improve depressive-like behavior in animal models of depression. In this study, we assessed the efficacy and tolerability of tipepidine combination therapy with citalopram in treatment of major depressive disorder (MDD).

METHODS

In a randomized, double-blinded, placebo-controlled clinical trial, 62 patients with MDD were assigned into two parallel groups to receive citalopram (up to 40 mg/day) plus placebo or citalopram plus tipepidine (30 mg twice daily) for 6 weeks. Participants were assessed with the Hamilton Rating Scale for Depression (HAM-D) at baseline and Weeks 2, 4, and 6.

RESULTS

Fifty-six patients completed the trial. The tipepidine group showed greater improvement in HAM-D scores from baseline to all three study time points (P = 0.048 for all). The remission and response-to-treatment rates were significantly higher in the tipepidine group (53.6% and 100%) compared to the placebo group (25.0% and 75%) at the study end-point (P = 0.029 and 0.005, respectively). The remission and response times in patients in the tipepidine group were also shorter compared with the placebo group (log-rank P = 0.020 and 0.004). There was no significant difference between the two groups in baseline parameters or frequency of side-effects.

CONCLUSION

Tipepidine combination therapy with citalopram can effectively improve symptoms of patients with MDD in a shorter period of treatment. However, further studies with larger sample sizes and longer follow-up treatment are needed to confirm our findings.

Predicting the Adult Clinical and Academic Outcomes in Boys With ADHD: A 7- to 10-Year Follow-Up Study in China

Background: Attention-deficit/hyperactivity disorder (ADHD) often persists into adulthood and causes adverse effects on social functioning. The present study aimed to widely investigate the predictors, particularly childhood intelligence quotient (IQ) and family environment factors, on adult clinical and academic outcomes in boys with ADHD. Methods: A total of 101 boys with ADHD in a Chinese Han ADHD cohort were followed up 7-10 years later. Baseline ADHD symptoms were evaluated using the parent version of the ADHD Rating Scale-IV (ADHD-RS-IV) and the Chinese version of the Conners' Parent Rating Scale-Revised (CPRS-48). The intelligence of the child was tested by the China-Wechsler Intelligence Scale for Children (C-WISC), and family function was assessed by the Family Environment Scale-Chinese Edition (FES-CV). Adult ADHD persistence was defined using DSM-IV criteria for ADHD, and academic outcome fell into two categories: higher academic level group (studying in senior middle school or above) and lower academic level group (studying in vocational secondary schools or below). Results: Stepwise multiple logistic regression analysis revealed that the father's character, impulsive-hyperactive index as measured by the CPRS-48, and intellectual-cultural index as measured by the FES-CV independently predicted clinical outcomes in adults, with an AUC of 0.770 (p < 0.001, 95% CI = 0.678-0.863). The corresponding sensitivity and specificity were 0.743 and 0.727, respectively. The father's education level, family economic level, and verbal IQ (VIQ) on the C-WISC independently predicted adult academic outcomes, with an AUC of 0.870 (p < 0.001, 95% CI = 0.796-0.944). The corresponding sensitivity and specificity were 0.813 and 0.783, respectively. Conclusion: Initial ADHD symptom severity and IQ, father's character and education level, and family atmosphere and function affect adult clinical and academic outcomes. Addressing these areas early may help to improve the prognosis of ADHD into adulthood.

Using the drug repositioning approach to develop a novel therapy, tipepidine hibenzate sustained-release tablet (TS-141), for children and adolescents with attention-deficit/hyperactivity disorder

BACKGROUND

Asverin® (tipepidine hibenzate) has been used as an antitussive for > 50 years in Japan. Studies revealed that tipepidine modulates monoamine levels, by inhibiting G-protein-activated inwardly rectifying potassium (GIRK) channels, expecting the potential therapeutic effects of tipepidine for attention-deficit/hyperactivity disorder (ADHD) in recent years. In this study, TS-141, a sustained-release tablet of tipepidine, was developed for the treatment of ADHD through a drug repositioning approach.

METHODS

The sustained-release profile of TS-141 in healthy adults was investigated, and tipepidine exposure in the plasma after the TS-141 administration was compared to that of Asverin in the phase I study. Phase II study was conducted to examine the effects of TS-141 30 (once a day), 60 (once a day), 120 mg (60 mg twice a day), or placebo, that is within the exposure in the maximum dosage of Asverin, in children and adolescents with ADHD, and was designed as an 8-week treatment, randomized, parallel group, double-blind, placebo-controlled trial recruiting 6-17-year-old children and adolescents diagnosed with ADHD. A total of 216 patients were randomized according to the CYP2D6 phenotype. The primary end-point was ADHD Rating Scale IV-J changes. Furthermore, effects of CYP2D6 phenotype on the efficacy in the subgroup analysis were investigated.

RESULTS

TS-141 had the sustained-release profile, and the CYP2D6 phenotype had effects on the plasma exposure of tipepidine. ADHD RS-IV-J scores in all TS-141 dosages decreased from their baseline scores; however, no significant difference was observed in ADHD RS-IV-J score changes between the placebo and TS-141-administered groups. In patients with intermediate metabolizer CYP2D6, ADHD RS-IV-J score changes in the 120 mg group tended to be larger than that in the placebo group.

CONCLUSIONS

ADHD RS-IV-J changes on TS-141 may depend on the interaction between the TS-141 dose and CYP2D6 phenotype, suggesting that further clinical trials should be conducted with careful consideration of polymorphism. Drug repositioning approach of TS-141 was attempted at the same dose as that of antitussive; however, dose setting according to the indication was necessary.

TRIAL REGISTRATION

Phase I study: JapicCTI-205235 (Registered 25 March 2020), Phase II study: JapicCTI-163244 (Registered 9 May 2016), https://www.clinicaltrials.jp/cti-user/trial/Show.jsp.

Emerging drugs for the treatment of attention-deficit hyperactivity disorder (ADHD)

INTRODUCTION

Attention-deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder affecting up to 5.3% of children and 2.5% of adults depending on the country considered. Current pharmacological treatments for ADHD are based on stimulant or non-stimulant medications, targeting dopaminergic and noradrenergic systems in the frontal cortex and dopaminergic system in the basal ganglia. These drugs are effective and safe for the majority of patients, whereas about 20% of treated patients do not tolerate current therapies or experience insufficient efficacy. The adequate treatment of ADHD is necessary to allow a proper social placement and prevent the acquisition of additional, more severe, comorbidities.

AREAS COVERED

We conducted a review of the scientific literature and of unpublished/ongoing clinical trials to summarize the advances made in the last 10 years (2010-2020) for the pharmacological treatment of ADHD. We found many pharmacological mechanisms beyond dopaminergic and noradrenergic ones have been investigated in patients.

EXPERT OPINION

Some emerging drugs for ADHD may be promising as add-on treatment especially in children, amantadine to enhance cognitive functions and tipepidine for hyperactivity/impulsivity. Stand-alone emerging treatments for ADHD include viloxazine and dasotraline, which will soon have more clinical data available to support market access requests.