Systematic review of atomoxetine data in childhood and adolescent attention-deficit hyperactivity disorder 2009-2011: focus on clinical efficacy and safety

The role of adrenergic neurotransmitter reuptake inhibitors in the ADHD armamentarium

INTRODUCTION

Adrenergic neurotransmitter reuptake inhibitors are gaining attention in treatment for attention-deficit hyperactivity disorder (ADHD). Due to their effects on norepinephrine, dopamine, and serotonin neurotransmission, they benefit both ADHD and comorbid disorders and have some other advantages including longer duration of action and fewer adverse effects compared to stimulants. There is continued interest in these agents with novel mechanisms of action in treatment of ADHD.

AREAS COVERED

The authors conducted a PubMed literature search using the following key words: 'ADHD' AND 'adrenergic reuptake inhibitors' OR 'nonstimulants' OR 'atomoxetine' OR 'Viloxazine' OR 'Dasotraline' OR 'Centanafadine' OR 'PDC-1421' OR 'Reboxetine' OR 'Edivoxetine' OR 'Bupropion' OR 'Venlafaxine' OR 'Duloxetine.' They reviewed FDA fact sheets of available medications for safety/tolerability studies and reviewed published clinical studies of these medications for treatment of ADHD.

EXPERT OPINION

Adrenergic neurotransmitter reuptake inhibitors fit the diverse needs of children and adolescents with ADHD with 1) poor tolerability to stimulants (e.g. due to growth suppression, insomnia, rebound irritability, co-morbid depression, anxiety and tic disorders, substance abuse or diversion concerns), 2) cardiac risks, and/or 3) need for extended duration of action. Their differences in receptor affinities and modulating effects support the unique benefits of individual agents.

Viloxazine for the Treatment of Attention Deficit Hyperactivity Disorder

Purpose of Review

Attention deficit hyperactivity disorder (ADHD) is a widely diagnosed neurodevelopmental disorder giving rise to symptoms of hyperactivity, impulsivity, and inattentiveness that can impair daily functioning. Stimulants, such as methylphenidate and amphetamines, are the mainstay of treatment for ADHD. However, nonstimulant drugs such as viloxazine, atomoxetine, guanfacine, and clonidine are becoming more popular due to minimal adverse effects when compared to stimulants.

Recent Findings

Viloxazine is a selective norepinephrine reuptake inhibitor (NRI) originally used to treat depression in adults with activity in both the noradrenergic as well as serotonergic pathways. Studies have demonstrated its efficacy for its use in the treatment of ADHD. Unlike stimulants, viloxazine has a decreased chance of substance abuse, drug dependance, and withdrawal symptoms upon the cessation of therapy. Additionally, dopamine levels in the nucleus accumbens after treatment with viloxazine are elevated considerably less in comparison with traditional stimulant ADHD treatments. Viloxazine provides an alternative, nonstimulant approach to treating ADHD.

Summary

Viloxazine is a recently approved, non-stimulant medication functions by inhibiting the uptake of norepinephrine which has been seen to be decreased in patients with ADHD. When patients do not respond to first-line stimulants, cannot tolerate the side effects, or have contraindications to stimulants, viloxazine may be a nonstimulant option offering patients an increasing arsenal of medications to treat ADHD.

Consequences of Acute or Chronic Methylphenidate Exposure Using Ex Vivo Neurochemistry and In Vivo Electrophysiology in the Prefrontal Cortex and Striatum of Rats

Methylphenidate (MPH) is among the main drugs prescribed to treat patients with attention-deficit and hyperactivity disease (ADHD). MPH blocks both the norepinephrine and dopamine reuptake transporters (NET and DAT, respectively). Our study was aimed at further understanding the mechanisms by which MPH could modulate neurotransmitter efflux, using ex vivo radiolabelled neurotransmitter assays isolated from rats. Here, we observed significant dopamine and norepinephrine efflux from the prefrontal cortex (PFC) after MPH (100 µM) exposure. Efflux was mediated by both dopamine and norepinephrine terminals. In the striatum, MPH (100 µM) triggered dopamine efflux through both sodium- and vesicular-dependent mechanisms. Chronic MPH exposure (4 mg/kg/day/animal, voluntary oral intake) for 15 days, followed by a 28-day washout period, increased the firing rate of PFC pyramidal neurons, assessed by in vivo extracellular single-cell electrophysiological recordings, without altering the responses to locally applied NMDA, via micro-iontophoresis. Furthermore, chronic MPH treatment resulted in decreased efficiency of extracellular dopamine to modulate NMDA-induced firing activities of medium spiny neurons in the striatum, together with lower MPH-induced (100 µM) dopamine outflow, suggesting desensitization to both dopamine and MPH in striatal regions. These results indicate that MPH can modulate neurotransmitter efflux in brain regions enriched with dopamine and/or norepinephrine terminals. Further, long-lasting alterations of striatal and prefrontal neurotransmission were observed, even after extensive washout periods. Further studies will be needed to understand the clinical implications of these findings.

Current and future nonstimulants in the treatment of pediatric ADHD: monoamine reuptake inhibitors, receptor modulators, and multimodal agents

Attention-deficit/hyperactivity disorder (ADHD), the single most common neuropsychiatric disorder with cognitive and behavioral manifestations, often starts in childhood and usually persists into adolescence and adulthood. Rarely seen alone, ADHD is most commonly complicated by other neuropsychiatric disorders that must be factored into any intervention plan to optimally address ADHD symptoms. With more than 30 classical Schedule II (CII) stimulant preparations available for ADHD treatment, only three nonstimulants (atomoxetine and extended-release formulations of clonidine and guanfacine) have been approved by the United States Food and Drug Administration (FDA), all of which focus on modulating the noradrenergic system. Given the heterogeneity and complex nature of ADHD in most patients, research efforts are identifying nonstimulants which modulate pathways beyond the noradrenergic system. New ADHD medications in clinical development include monoamine reuptake inhibitors, monoamine receptor modulators, and multimodal agents that combine receptor agonist/antagonist activity (receptor modulation) and monoamine transporter inhibition. Each of these "pipeline" ADHD medications has a unique chemical structure and differs in its pharmacologic profile in terms of molecular targets and mechanisms. The clinical role for each of these agents will need to be explored with regard to their potential to address the heterogeneity of individuals struggling with ADHD and ADHD-associated comorbidities. This review profiles alternatives to Schedule II (CII) stimulants that are in clinical stages of development (Phase 2 or 3). Particular attention is given to viloxazine extended-release, which has completed Phase 3 studies in children and adolescents with ADHD.

The effect of autistic traits on response to and side-effects of pharmacological ADHD treatment in children with ADHD: results from a prospective clinical cohort

Background

Attention deficit hyperactivity disorder (ADHD) is a common childhood behavioral condition that globally affects an average of around 5% of children and is associated with several adverse life outcomes. Comorbidity with autism spectrum disorder (ASD) is highly prevalent. Pharmacological treatment for ADHD symptoms has been shown to be effective. However, the prevailing perception is that children with ADHD and concomitant ASD symptoms report poorer efficacy and more side effects. This has been supported by studies on this population, but prospective studies directly comparing children with ADHD and different levels of ASD symptoms are lacking. We aimed to assess if children with ADHD and concomitant ASD symptoms differ regarding effects and side-effects of pharmacological ADHD treatment compared to children with ADHD without ASD traits. This is to our knowledge the second study to directly compare the effect of ADHD medication between ADHD patients with different levels of ASD symptoms.

Methods

In a non-randomized, observational, prospective cohort study, 323 patients aged 6 to 17 years who were diagnosed with ADHD and starting pharmacological treatment were divided into two groups: one with high level of ASD symptoms (ASD group, N=71) and one with low level of ASD symptoms (non-ASD group, N = 252). Treatment outcome was measured as ADHD symptoms, and evaluated using the Swanson, Nolan and Pelham Teacher and Parent ADHD rating scale-version IV (SNAP-IV). Side-effects were evaluated using the Pediatric Side Effects Checklist (P-SEC), at 3 months follow-up.

Results

From baseline to 3 months, there was no significant difference in neither treatment effect nor number of clinically significant adverse events experienced between the ASD group and the non-ASD group.

Conclusions

Our results did not implicate that ADHD patients with concomitant ASD symptoms have decreased treatment effect of ADHD medication than patients with ADHD without concomitant ASD symptoms. Neither did the results support that ADHD patients with ASD symptoms experienced significantly more side-effects than ADHD patients without ASD symptoms. Although, we did not analyze different medications separately, this is in line with the only previous study directly comparing methylphenidate treatment in children with or without ASD.

Trial registration

NCT02136147, May 12, 2014.

The Effects of Drug Treatments for ADHD in Measures of Cognitive Performance

Based on core symptoms of inattention and deficient impulse control, and the identification of effective pharmacotherapies such as amphetamine (AMP; Adderall^®), methylphenidate (MPH; Ritalin^®), and atomoxetine (ATX; Strattera^®), ADHD is a clinical condition which provides opportunity for translational research. Neuropsychological tests such as the 5-Choice and Continuous Performance Tasks, which measure aspects of attention and impulse control in animals and humans, provide scope for both forward (animal to human) and reverse (human to animal) translation. Rodent studies support pro-attentive effects of AMP and MPH and effectiveness in controlling some forms of impulsive behavior. In contrast, any pro-attentive effects of ATX appear to be less consistent, the most reliable effects of ATX are recorded in tests of impulsivity. These differences may account for AMP and MPH being recognized as first-line treatments for ADHD with a higher efficacy relative to ATX. DSM-5 classifies three "presentations" of ADHD: predominantly inattentive type (ADHD-I), predominantly hyperactive/impulsive type (ADHD-HI), or combined (ADHD-C). Presently, it is unclear whether AMP, MPH, or ATX has differential levels of efficacy across these presentation types. Nonetheless, these studies encourage confidence for the forward translation of NCEs in efforts to identify newer pharmacotherapies for ADHD.

A Phase 3, Placebo-Controlled Trial of Once-Daily Viloxazine Extended-Release Capsules in Adolescents With Attention-Deficit/Hyperactivity Disorder

PURPOSE

This phase 3 clinical trial evaluated the efficacy and safety of viloxazine extended-release capsules (VLX-ER) as a monotherapy for attention-deficit/hyperactivity disorder (ADHD) in adolescents (12-17 years).

METHODS

Eligible subjects (n = 310) were randomized to receive once-daily 200 and 400 mg VLX-ER, or placebo for 6 weeks. The primary efficacy end point was change from baseline (CFB) at the end of study (EOS) in ADHD Rating Scale-5 Total score. Key secondary end points were Clinical Global Impression-Improvement score at EOS, CFB at EOS in Conners 3-Parent Short Form Composite T-score, and CFB at EOS in Weiss Functional Impairment Rating Scale-Parent Total average score.

RESULTS

In the 200-mg/d and 400-mg/d VLX-ER treatment groups, a significant improvement was found in the CFB at EOS in ADHD Rating Scale-5 Total (P = 0.0232, P = 0.0091) and Inattention (P = 0.0424, P = 0.0390) and Hyperactivity/Impulsivity (P = 0.0069, P = 0.0005) subscale scores versus placebo. The Clinical Global Impression-Improvement score was significantly improved at EOS in the 200-mg/d and 400-mg/d VLX-ER groups versus placebo (P = 0.0042, P = 0.0003). The Conners 3-Parent Short Form composite T-score and Weiss Functional Impairment Rating Scale-Parent Total average score exhibited improvement in both VLX-ER groups; however, the difference versus placebo was not statistically significant. The most common treatment-related adverse events were somnolence, headache, decreased appetite, nausea, and fatigue. The adverse event-related discontinuation rates were <5% in all groups.

CONCLUSIONS

Viloxazine extended-release demonstrated statistically significant and clinically meaningful improvement in ADHD symptoms in adolescents and was generally well tolerated.

Methylphenidate and atomoxetine treatment negatively affect physical growth indexes of school-age children and adolescents with attention-deficit/hyperactivity disorder

AIM

To determine the effects of drug therapy on the physical growth of school-age children and adolescents with attention-deficit/hyperactivity disorder (ADHD).

METHOD

The medical records of 86 participants (average age: 8.9 ± 2.2 years) with ADHD prescribed methylphenidate (MPH) or atomoxetine (ATX) for ≥24 weeks from the Children's Hospital of Chongqing Medical University were analysed.

RESULTS

The Z-scores of height, weight and body mass index (BMI) of children with ADHD decreased significantly over the first six months of MPH treatment (P < 0.001). The slopes of the fitting lines after the first six months of MPH (-0.18, -0.58 and -0.69, respectively) returned over the entire treatment (the slopes changed to -0.027, -0.26 and -0.20, respectively). For ATX, the Z-scores of height of children decreased significantly over the first six months (P < 0.001), but the Z-scores of weight and BMI did not (P > 0.05). The slopes of the fitting lines after the first six months of ATX (-0.058, -0.032 and 0.0094, respectively) changed over the entire treatment (slopes were 0.16, 0.52 and 0.26, respectively). Children taking MPH were more likely to report decreased appetite (P < 0.05). The weight and BMI of the children receiving MPH were significantly correlated with decreased appetite (P < 0.01).

CONCLUSION

The physical growth indexes (PGIs) of school-age children and adolescents with ADHD were negatively affected while taking MPH, and these effects were gradually mitigated with continued treatment. ATX hardly had negative effects on weight and BMI. Neither MPH nor ATX had a significant negative effect on the height of children in long-term ADHD treatment. It is necessary for clinicians to consider children's diet during treatment.

Atomoxetine in Attention-Deficit/Hyperactivity Disorder in Children With and Without Comorbid Mood Disorders

Objectives: Mood disorders are commonly associated with attention-deficit/hyperactivity disorder (ADHD), adding to the clinical complexity. Some symptoms associated with ADHD are often associated with an increase in emotional disorders and depression. Hence, the management of comorbid mood symptoms in the context of ADHD represents a particularly difficult clinical challenge. Few studies in literature, and probably none in the Arab world, have investigated the impact of individual common comorbid disorders on the efficacy of atomoxetine (a nonstimulant norepinephrine reuptake inhibitor) as a monotherapy for the treatment of these comorbid mood symptoms. Therefore, our aim was to investigate the effect of atomoxetine in a sample of drug-naive Egyptian children with ADHD, with and without comorbid mood disorders. Methods: A prospective, naturalistic, open-label study. Results: Atomoxetine is an effective treatment for the symptoms of ADHD in the presence of comorbid mood disorder, but with a slower rate of improvement than if applied in the absence of mood disorder; in addition, our study showed improvement regarding the depressive symptoms in the mood group after 1 month. Conclusions: The study highlighted that atomoxetine is an effective treatment for ADHD in the presence of comorbid mood disorder, and improves depressive symptoms in the mood group. It also predicts mild resistance to the effects of atomoxetine on ADHD with slower improvement than those with ADHD only.

A novel approach to intra-individual performance variability in ADHD

Patients with attention deficit/(hyperactivity) disorder (AD(H)D) show increased intra-individual variability (IIV) in behavioral performance. This likely reflects dopaminergic deficiencies. However, the precise performance profile across time and the pattern of fluctuations within it have not yet been considered, partly due to insufficient methods. Yet, such an analysis may yield important theory-based implications for clinical practice. Thus, in a case-control cross-sectional study, we introduce a new method to investigate performance fluctuations in patients with ADD (n = 76) and ADHD (n = 67) compared to healthy controls (n = 45) in a time estimation task. In addition, we also evaluate the effects of methylphenidate (MPH) treatment on this performance pattern in 29 patients with AD(H)D. Trial-by-trial differences in performance between healthy controls and patients with AD(H)D do not persist continuously over longer time periods. Periods during which no differences in performance between healthy controls and patients occur alternate with periods in which such differences are present. AD(H)D subtype and surprisingly also medication status does not affect this pattern. The presented findings likely reflect (phasic) deficiencies of the dopaminergic system in patients with AD(H)D which are not sufficiently ameliorated by first-line pharmacological treatment. The presented findings carry important clinical and scientific implications.

Methylphenidate-induced Exacerbation of Chorea in a Child Resolved with Switching to Atomoxetine

Choreiform movements have been reported with stimulant medications, especially in adults. There is only limited evidence on the management of such reactions in children with attention deficit hyperactivity disorder. Hereby, we present the exacerbation of chorea with long-acting methylphenidate use in a 6-year-old child with acute rheumatic fever which resolved with switching to atomoxetine.

Temperament correlates in adult ADHD: A systematic review★★

BACKGROUND

Attention deficit and hyperactivity disorder (ADHD) is the most common neurodevelopmental disorder in children, but adult-ADHD is still an under-diagnosed and untreated condition. Treating adult-ADHD is complex and requires effective strategies for ADHD symptoms and comorbidities. Because of its high comorbidity rate with mood disorders and the growing interest in symptoms of emotional dysregulation in these patients, our aim was to collect studies that investigated temperament correlates in adult people with ADHD, to better understand the association between them and the eventual role of temperament as a prognostic-therapeutic marker.

METHODS

We performed a systematic review of the literature. We included only studies that measured temperament traits in ADHD adults using the Temperament Evaluation of Memphis, Paris and San Diego-Auto-questionnaire (TEMPS-A) or the Temperament and Character Inventory (TCI).

RESULTS

We retrieved 15 papers that used the TCI and 6 papers that used the TEMPS-A. In the TCI studies, ADHD was associated with high scores on Novelty Seeking and Harm Avoidance and low scores on Persistence. For the TEMPS-A studies, ADHD and Bipolar Disorders share some similarities in temperament scores, except for the hyperthymic temperament score.

LIMITATIONS

A comparison between the TCI and TEMPS-A results was not possible. The number of papers included was small. Among them, the type of sample, the number of recruited subjects and the ADHD assessment were very different.

CONCLUSIONS

The majority of ADHD individuals share temperament traits such as lability, irritability and excessiveness of emotional responses. Further research is needed to better understand whether temperament influences the pharmacological response of ADHD patients and whether temperament scores affect the long-term therapeutic outcome.

Attention-deficit/hyperactivity disorder in elite athletes: a narrative review

Attention-deficit/hyperactivity disorder (ADHD) is a common brain developmental disorder in the general population that may be even more prevalent in elite athletes in certain sports. General population studies of ADHD are extensive and have reported on prevalence, symptoms, therapeutic and adverse effects of treatment and new clinical and research findings. However, few studies have reported on prevalence, symptoms and treatments of ADHD in elite athletes. This narrative review summarises the literature on symptoms, comorbidities, effects of ADHD on performance and management options for elite athletes with ADHD. The prevalence of ADHD in student athletes and elite athletes may be 7%–8%. The symptoms and characteristics of ADHD play a role in athletes’ choice of a sport career and further achieving elite status. Proper management of ADHD in elite athletes is important for safety and performance, and options include pharmacologic and psychosocial treatments.

A Signature of Attention-Elicited Electrocortical Activity Distinguishes Response From Non-Response to the Non-Stimulant Atomoxetine in Children and Adolescents With ADHD

OBJECTIVE

Atomoxetine has several characteristics that make it an attractive alternative to stimulants for treating ADHD, but there are currently no tests identifying individuals for whom the medication should be a first-line option.

METHOD

Within the ADHD Controlled Trial Investigation Of a Non-stimulant (ACTION) study, we examined neuro-cortical activity in 52 youth with ADHD. Baseline event-related potentials (ERP) were compared between those who subsequently responded to 6 weeks of atomoxetine versus those who did not.

RESULTS

Responders were distinguished by significantly lower auditory oddball N2 amplitudes than both non-responders and typically developing controls, particularly in the right frontocentral region ( p = .002, Cohen's d = 1.1). Leave-one-out cross validation determined that N2 amplitude in this region was able to accurately predict non-responders with a specificity of 80.8%. There were no P3 differences between responders and non-responders.

CONCLUSION

The N2 amplitude is a biomarker that may have utility in predicting response to atomoxetine for youth with ADHD.

The Modulation of Neural Noise Underlies the Effectiveness of Methylphenidate Treatment in Attention-Deficit/Hyperactivity Disorder

BACKGROUND

Various lines of research suggest that the stability of neural processes is low in attention-deficit/hyperactivity disorder (ADHD). Considering overarching neural principles, this lack of stability relates to increased levels of neural noise. However, no study has directly examined neural noise in ADHD. Likewise, it is unknown whether the modulation of neural noise reflects a mechanistic link as to why methylphenidate (MPH) is effective in treating impulsivity in ADHD.

METHODS

We compared neural noise between 29 juvenile patients with ADHD and 32 healthy control subjects and examined the effects of MPH. We examined 1/f neural noise of electroencephalogram data collected while participants performed a response inhibition (Go/NoGo) task.

RESULTS

Specific during NoGo trials, children with ADHD showed more neural noise than healthy control subjects. This was especially the case with regard to the theta frequency band, which is very closely related to cognitive control. MPH treatment reduced neural noise in ADHD to the level of healthy control subjects. Correlational analyses showed a direct relationship between decreases in neural noise and increases in behavioral performance. Mechanistically, this can be explained by the MPH-induced increase in dopaminergic neurotransmission that enhances the signal-to-noise ratio in neural networks and thus reduces neural noise.

CONCLUSIONS

This study is the first to demonstrate increased (pink) neural noise in patients with ADHD and its reduction through MPH treatment. The study reveals an important mechanistic link as to why MPH is effective in treating impulsivity in ADHD.

Pharmacological treatment of attention-deficit hyperactivity disorder comorbid with an anxiety disorder: a systematic review

The purpose of this study was to conduct a systematic review of the pharmacological options available to treat patients diagnosed with attention-deficit hyperactivity disorder and anxiety disorder, for generating evidence on the safest, most-effective and tolerable pharmacotherapy. To this end, a systematic search was performed in three electronic databases (Medline, Scopus and Directory of Open Access Journals; December 2017). Randomized, double-blind, parallel-design clinical trials evaluating the efficacy, safety or tolerability of therapies for attention-deficit hyperactivity disorder and anxiety disorder in children and adolescents or adults were considered. A total of 1960 articles were retrieved from the databases, of which five studies were included in the qualitative synthesis. Two of these studies evaluated the drug atomoxetine, another study evaluated desipramine, and the remaining two studies evaluated methylphenidate, with fluvoxamine being associated with methylphenidate in one of the trials. Owing to the high heterogeneity among studies, it was not possible to combine data for meta-analyses. Although only few studies have been evaluated in this systematic review, the results point to a more significant benefit of atomoxetine. This is probably because this drug was studied in a wider age range and evaluated by more specific scales for both disorders. To further strengthen this evidence, randomized, controlled and multicenter clinical trials with larger sample sizes should be conducted.

Dasotraline in Children with Attention-Deficit/Hyperactivity Disorder: A Six-Week, Placebo-Controlled, Fixed-Dose Trial

OBJECTIVE

Dasotraline is a potent inhibitor of presynaptic dopamine and norepinephrine reuptake with a pharmacokinetic profile characterized by slow absorption and a long elimination half-life. The aim of this study was to evaluate the efficacy and safety of dasotraline in children with attention-deficit/hyperactivity disorder (ADHD).

METHODS

Children aged 6-12 years with a Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnosis of ADHD were randomized to 6 weeks of double-blind once-daily treatment with dasotraline (2 or 4 mg) or placebo. The primary efficacy endpoint was change from baseline in the ADHD Rating Scale Version IV-Home Version (ADHD RS-IV HV) total score at week 6.

RESULTS

A total of 342 patients were randomized to dasotraline or placebo (mean age 9.1 years, 66.7% male). Treatment with dasotraline was associated with significant improvement at study endpoint in the ADHD RS-IV HV total score for the 4 mg/day dose versus placebo (-17.5 vs. -11.4; p < 0.001; effect size [ES], 0.48), but not for the 2 mg/day dose (-11.8 vs. -11.4; ns; ES, 0.03). A regression analysis confirmed a significant linear dose-response relationship for dasotraline. Significant improvement for dasotraline 4 mg/day dose versus placebo was also observed across the majority of secondary efficacy endpoints, including the Clinical Global Impression (CGI)-Severity score, the Conners Parent Rating Scale-Revised scale (CPRS-R) ADHD index score, and subscale measures of hyperactivity and inattentiveness. Discontinuation rates due to adverse events (AEs) were higher in the dasotraline 4 mg/day group (12.2%) compared with the 2 mg/day group (6.3%) and placebo (1.7%). The most frequent AEs associated with dasotraline were insomnia, decreased appetite, decreased weight, and irritability. Psychosis-related symptoms were reported as AEs by 7/219 patients treated with dasotraline in this study. There were no serious AEs or clinically meaningful changes in blood pressure or heart rate on dasotraline.

CONCLUSION

In this placebo-controlled study, treatment with dasotraline 4 mg/day significantly improved ADHD symptoms and behaviors, including attention and hyperactivity, in children aged 6-12 years. The most frequently reported AEs observed on dasotraline included insomnia, decreased appetite, decreased weight, and irritability.

Cardiovascular Effects of Drugs Used to Treat Attention-Deficit/Hyperactivity Disorder: Part 1: Epidemiology, Pharmacology, and Impact on Hemodynamics and Ventricular Repolarization

Attention-deficit/hyperactivity disorder (ADHD) is a clinical syndrome characterized by persistent inattention, impulsivity, and hyperactivity. It is most commonly encountered in children and adolescents but may persist into adulthood. A variety of psychostimulant and nonpsychostimulant medications have proven to be successful in reducing inattention, impulsivity, and hyperactivity in those with ADHD. Psychostimulants used to treat ADHD include methylphenidate and related drugs and various amphetamine preparations. Non-psychostimulant medications used to treat ADHD include atomoxetine and two alpha-2 adrenergic agonists: guanfacine extended-release and clonidine extended-release. The psychostimulants and atomoxetine have been shown, on average, to increase heart rate by 3-10 beats/min, systolic blood pressure by 3-8 mm Hg, and diastolic blood pressure by 2-14 mm Hg. These drugs may also delay ventricular repolarization. The alpha-2 adrenergic agonists may reduce heart rate and blood pressure. For these reasons, there is concern about the safety of psychostimulant and nonpsychostimulant medications in patients with ADHD. In part 1 of this review, we discuss the epidemiology and natural history of ADHD, describe the pharmacology of drugs used to treat ADHD, and discuss in detail studies assessing the effects of ADHD drugs on blood pressure, heart or pulse rate, and electrocardiographic indices of ventricular repolarization.

Systemic administration of guanfacine improves food-motivated impulsive choice behavior primarily via direct stimulation of postsynaptic α2A-adrenergic receptors in rats

Impulsive choice behavior, which can be assessed using the delay discounting task, is a characteristic of various psychiatric disorders, including attention-deficit/hyperactivity disorder (ADHD). Guanfacine is a selective α_2A-adrenergic receptor agonist that is clinically effective in treating ADHD. However, there is no clear evidence that systemic guanfacine administration reduces impulsive choice behavior in the delay discounting task in rats. In the present study, we examined the effect of systemic guanfacine administration on food-motivated impulsive choice behavior in rats and the neuronal mechanism underlying this effect. Repeated administration of either guanfacine, methylphenidate, or atomoxetine significantly enhanced impulse control, increasing the number of times the rats chose a large but delayed reward in a dose-dependent manner. The effect of guanfacine was significantly blocked by pretreatment with an α_2A-adrenergic receptor antagonist. Furthermore, the effect of guanfacine remained unaffected in rats pretreated with a selective noradrenergic neurotoxin, consistent with a post-synaptic action. In contrast, the effect of atomoxetine on impulsive choice behavior was attenuated by pretreatment with the noradrenergic neurotoxin. These results provide the first evidence that systemically administered guanfacine reduces impulsive choice behavior in rats and that direct stimulation of postsynaptic, rather than presynaptic, α_2A-adrenergic receptors is involved in this effect.

Neurodevelopmental disorders

Neurodevelopmental disorders such as attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder, although most commonly considered in childhood, can be lifelong conditions. In this Personal View that is shaped by clinical experience and research, we adopt a conceptual approach. First, we discuss what disorders are neurodevelopmental and why such a grouping is useful. We conclude that both distinction and grouping are helpful and that it is important to take into account the strong overlap across neurodevelopmental disorders. Then we highlight some challenges in bridging research and clinical practice. We discuss the complexity of clinical phenotypes and the importance of the social context. We also argue the importance of viewing neurodevelopmental disorders as traits but highlight that this is not the only approach to use. Finally, we consider developmental change across the life-span. Overall, we argue strongly for a flexible approach in clinical practice that takes into consideration the high level of heterogeneity and overlap in neurodevelopmental disorders and for research to link more closely to what is observed in real-life practice.

Comparative efficacy and tolerability of pharmacological interventions for attention-deficit/hyperactivity disorder in children, adolescents and adults: protocol for a systematic review and network meta-analysis

INTRODUCTION

Attention-deficit/hyperactivity disorder (ADHD) is a major public health issue. Pharmacological treatments play an important role in the multimodal treatment of ADHD. Currently, there is a lack of up-to-date and comprehensive evidence on how available ADHD drugs compare and rank in terms of efficacy and tolerability, in children or adolescents as well as in adults. We will conduct a network meta-analysis (NMA), integrating direct and indirect comparisons from randomised controlled trials (RCTs), to rank pharmacological treatments for ADHD according to their efficacy and tolerability profiles.

METHODS AND ANALYSIS

We will search a broad range of electronic databases, including PubMed, MEDLINE, EMBASE, PsycINFO, ERIC and Web of Science, with no date or language restrictions. We will also search for unpublished studies using international clinical trial registries and contacting relevant drug companies. We will identify and include available parallel-group, cross-over and cluster randomised trials that compare methylphenidate, dexmethylphenidate, amphetamine derivatives (including lisdexamfetamine), atomoxetine, clonidine, guanfacine, bupropion or modafinil (as oral therapy) either with each other or to placebo, in children, adolescents or adults with ADHD. Primary outcomes will be efficacy (indicated by reduction in severity of ADHD core symptoms measured on a standardised scale) and tolerability (the proportion of patients who left a study early due to side effects). Secondary outcomes will be global functioning, acceptability (proportion of patients who left the study early by any cause) and changes in blood pressure and body weight. NMA will be conducted in STATA within a frequentist framework. The quality of RCTs will be evaluated using the Cochrane risk of bias tool, and the quality of the evidence will be assessed using the GRADE approach. Subgroup and sensitivity analyses will be conducted to assess the robustness of the findings.

ETHICS AND DISSEMINATION

No ethical issues are foreseen. Results from this study will be published in a peer-reviewed journal and possibly presented at relevant national and international conferences.

TRIAL REGISTRATION NUMBER

CRD42014008976.

A review of the efficacy of atomoxetine in the treatment of attention-deficit hyperactivity disorder in children and adult patients with common comorbidities

Attention-deficit hyperactivity disorder (ADHD) is a common neuropsychiatric disorder that is often diagnosed during childhood, but has also increasingly been recognized to occur in adults. Importantly, up to 52% of children (including adolescents) and 87% of adults with ADHD also have a comorbid psychiatric disorder. The presence of a comorbid disorder has the potential to impact diagnosis and could affect treatment outcomes. Atomoxetine is a nonstimulant treatment for ADHD. Despite numerous published studies regarding efficacy of atomoxetine in the treatment of ADHD in patients with comorbid disorders, there is limited information about the impact of individual common comorbid disorders on the efficacy of atomoxetine for ADHD, especially with regard to adults. Moreover, a cumulative review and assessment of these studies has not been conducted. For this reason, we performed a literature review to find, identify, and cumulatively review clinical studies that examined the efficacy of atomoxetine in the treatment of patients with ADHD and comorbid psychiatric disorders. We found a total of 50 clinical studies (37 in children; 13 in adults) that examined the efficacy of atomoxetine in patients with ADHD and a comorbid disorder. The comorbidities that were studied in children or in adults included anxiety, depression, and substance use disorder. Overall, the presence of comorbidity did not adversely impact the efficacy of atomoxetine in treatment of ADHD symptoms in both patient populations. In the studies identified and assessed in this review, atomoxetine did not appear to exacerbate any of the comorbid conditions and could, therefore, be an important therapy choice for the treatment of ADHD in the presence of comorbid disorders.

Clinical and neurobiological factors in the management of treatment refractory attention-deficit hyperactivity disorder

Attention-deficit/hyperactivity disorder (ADHD) is a highly prevalent mental disorder of childhood, which often continues into adolescence and adulthood. Stimulants such as methylphenidate (MPH) and non-stimulants such as atomoxetine are effective medications for the treatment of ADHD. However, about 30% of patients do not respond to these medications. Pharmacological treatment for ADHD, although highly effective, is associated with marked variabilities in clinical response, optimal dosage needed and tolerability. This article provides an overview of up-to-date knowledge regarding the clinical and neurobiological factors which contribute to and help predict treatment-refractory ADHD. Pharmacogenetic, pharmacogenomics and neuroimaging studies are still controversial with respect to determining the associations between response to medication and genetic factors, thereby resulting in hypotheses that differences in the genetic factors and neuroimaging findings contribute to treatment outcome. Much research on the potential role of genotype in pharmacological effects has focused on the catecholaminergic gene related to executive functions. Many neuroimaging studies have also reported a relationship between treatment response and common patterns of brain structure or activity according to various genetic polymorphisms. When children, adolescents and adults with ADHD do not respond to MPH, we should consider additional pharmacological options, including other classes of psychostimulants, the nonstimulant atomoxetine, bupropion, tricyclic antidepressant, clonidine, guanfacine and lisdexamphetamine. Prudent choice of an appropriate medication and active engagement of children, parents, and teachers in daily management may help to ensure long-term adherence. Therefore, additional research might help to optimize the treatment of children, adolescents and adults with ADHD and to find new options for the treatment of patients who do not respond to stimulants and the other medications. Because these findings should be interpreted cautiously, further studies are needed to elucidate these issues more clearly.

Guanfacine Extended Release: A New Pharmacological Treatment Option in Europe

Children/adolescents with attention-deficit/hyperactivity disorder (ADHD) may have a poor or inadequate response to psychostimulants or be unable to tolerate their side-effects; furthermore, stimulants may be inappropriate because of co-existing conditions. Only one non-stimulant ADHD pharmacotherapy, the noradrenaline transporter inhibitor atomoxetine, is currently approved for use in Europe. We review recent advances in understanding of the pathophysiology of ADHD with a focus on the roles of catecholamine receptors in context of the α2A-adrenergic receptor agonist guanfacine extended release (GXR), a new non-stimulant treatment option in Europe. Neuroimaging studies of children/adolescents with ADHD show impaired brain maturation, and structural and functional anomalies in brain regions and networks. Neurobiological studies in ADHD and medication response patterns support involvement of monoaminergic neurotransmitters (primarily dopamine and noradrenaline). Guanfacine is a selective α2A-adrenergic receptor agonist that has been shown to improve prefrontal cortical cognitive function, including working memory. The hypothesized mode of action of guanfacine centres on direct stimulation of post-synaptic α2A-adrenergic receptors to enhance noradrenaline neurotransmission. Preclinical data suggest that guanfacine also influences dendritic spine growth and maturation. Clinical trials have demonstrated the efficacy of GXR in ADHD, and it is approved as monotherapy or adjunctive therapy to stimulants in Canada and the USA (for children and adolescents). GXR was approved recently in Europe for the treatment of ADHD in children and adolescents for whom stimulants are not suitable, not tolerated or have been shown to be ineffective. GXR may provide particular benefit for children/adolescents who have specific co-morbidities such as chronic tic disorders or oppositional defiant disorder (or oppositional symptoms) that have failed to respond to first-line treatment options.

Clinical Impact of Not Achieving Recommended Dose on Duration of Atomoxetine Treatment in Adults with Attention-Deficit/Hyperactivity Disorder

Aim

To compare atomoxetine (ATX) length of therapy (LoT) among adults with ADHD who reached the recommended dose of 80 mg/day (ATX ≥ 80) versus those who did not (ATX < 80) analyzed separately in patients prescribed ATX as monotherapy (mono) and in combination with other ADHD medications (combo).

Methods

This was a retrospective observational cohort study of the Truven Health Marketscan Commercial Claims Database from January 1, 2006–September 30, 2013, with a 6‐month preindex period free of ATX (1st ATX claim as index event) and a 1‐year follow‐up. LoT during follow‐up was calculated using prescription claim fill dates and included all days with medication on hand regardless of treatment gaps.

Results

Only 45.0% of the 36,076 mono and 77.9% of the 1548 combo patients reached an ATX dose of ≥80 mg/day in 1‐year follow‐up. When patients filled at least one 80 mg prescription, their total days of therapy over the course of a year were significantly greater than if they did not (mono: 159.3 vs. 65.6 days; combo: 237.4 vs. 172.0; P < 0.0001). Across all timepoints examined (Day 14, 30, 60, 90, 210) for mono and combo, ATX ≥ 80 versus ATX < 80 patients had greater mean doses (P < 0.0001). Combo patients had longer ATX LoT than mono patients regardless if they reached 80 mg or not (P < 0.0001), but mono patients LoT was 93.8 days longer for ATX ≥ 80 versus ATX < 80 patients compared to 65.5 days for combo patients. Of patients reaching 80 mg/day, 71.7% of mono and 62.8% of combo patients did so by Day 30. For mono ATX ≥ 80 and ATX < 80 patients, LoT was significantly (P < 0.0001) less in previously treated patients compared to naive patients.

Conclusion

Ensuring adult ADHD patients are treated with ATX at a target dose of 80 mg/day is an important clinical consideration for maximizing patient days on therapy, which can be important for treatment optimization.

The Safety of Atomoxetine for the Treatment of Children and Adolescents with Attention-Deficit/Hyperactivity Disorder: A Comprehensive Review of Over a Decade of Research

Atomoxetine is a noradrenergic reuptake inhibitor prescribed for attention-deficit/hyperactivity disorder (ADHD) that first gained approval in the USA in 2002 and has been authorized in 97 countries worldwide. The aim of this paper is to comprehensively review publications that addressed one or more of seven major safety topics relevant to atomoxetine treatment of children and adolescents (aged ≥6 years) diagnosed with ADHD. While the review focuses on children and adolescents, publications in which data from patients aged >18 years and from 6 to 18 years were analyzed in the same dataset were included. Using a predefined search strategy, including agreement of two reviewers when selecting papers, reduced the potential for bias. Using this process, we identified 70 eligible papers (clinical trials, epidemiological studies, and case reports) across the seven topics. We also referred to the European Summary of Product Characteristics (SPC) and US label. We found 15 papers about suicidality, three about aggression/hostility, seven about psychosis/mania, six about seizures, seven about hepatic effects, 29 about cardiovascular effects, and 28 about growth and development. The main findings (i.e., those from the largest and most well-conducted studies/analyses) are as follows. A large register-based study of pediatric and adult patients (6818 received atomoxetine) calculated a hazard ratio of 0.96 for suicide-related events during treatment with atomoxetine, and a meta-analysis of 23 placebo-controlled studies (N = 3883), published in 2014, found no completed suicides and no statistically significant association between atomoxetine and suicidality. The frequency of aggression/hostility was not statistically significantly higher with atomoxetine, e.g., experienced by 1.6 % (N = 21/1308) of atomoxetine-treated patients versus 1.1 % (N = 9/806) of placebo-treated patients in one meta-analysis. Symptoms of psychosis and mania were mainly observed in patients with comorbid bipolar disorder/depression. Based on spontaneous reports, during a 2-year period when 2.233 million adult and pediatric patients were exposed to atomoxetine, the reporting rate for seizures was 8 per 100,000 patients. In the manufacturer's database, atomoxetine was a "probable cause" of three hepatic adverse events (AEs) (all reversible hepatitis), and 133 hepatic AEs had possible confounding factors and were "possibly related" to atomoxetine, during 4 years when atomoxetine exposure had reached about 4.3 million patients. Rare cases of severe liver injury are described in the US label and European SPC; a case requiring liver transplantation is described in the US label. In a comprehensive review of a clinical trials database (N = 8417 received atomoxetine), most pediatric patients experienced modest increases in heart rate and blood pressure, and 8-12 % experienced more pronounced changes (≥20 bpm, ≥15 to 20 mmHg). However, in three long-term analyses (≥2 years), blood pressure was within age norms, and few patients discontinued due to cardiovascular AEs. As described in the European SPC, QT interval prolongation is uncommon, e.g., in an open-label study, 1.4 % of 711 children and adolescents had prolonged QTc intervals (≥450 ms in males, ≥470 ms in females) that were not clinically significant at ≥3 years of treatment with atomoxetine. The European SPC warns about potential QT interval prolongation in patients with a personal or family history, or if atomoxetine is administered with other drugs that potentially affect the QT interval. Decreases in growth (weight and height gain) occurred and were greatest in patients of above average weight and height, but appeared to recover over 2-5 years of atomoxetine treatment. In conclusion, suicidality, aggression/hostility, psychosis, seizures, liver injuries, and prolonged QT interval are uncommon or rare in children and adolescents treated with atomoxetine, based on data from the predefined search and from the European SPC. Overall, the data that we assessed from our search do not suggest that associations exist between atomoxetine and suicidality or seizures. The data also suggest that an association may not exist between atomoxetine and aggression/hostility. While atomoxetine may affect the cardiovascular system, the data suggest these effects are not clinically significant in most patients. Reductions in growth appear to be reversible in the long term.

Post Hoc Analysis of Potential Predictors of Response to Atomoxetine for the Treatment of Adults with Attention-Deficit/Hyperactivity Disorder using an Integrated Database

BACKGROUND

Responses to atomoxetine vary for individual patients with attention-deficit/hyperactivity disorder (ADHD). However, we do not know whether any factors can be used to reliably predict how individuals with ADHD will respond to treatment.

OBJECTIVE

Our objective was to evaluate background variables that facilitate early identification of those adults with ADHD who are likely to respond to treatment with atomoxetine.

METHODS

We pooled data for atomoxetine-treated adults with ADHD from 12 clinical trials for a short-term (10-week) analysis, and from 11 clinical trials for a long-term (24-week) analysis. Patients not meeting a response definition [≥30 % reduction in Conners' Adult ADHD Rating Scales-Investigator Rated: Screening Version (CAARS-Inv:SV) total score and Clinical Global Impressions of ADHD Severity Scale (CGI-S) score ≤3 at endpoint], or who discontinued, were defined as non-responders. Another definition of response (≥30 % reduction in CAARS-Inv:SV total score at endpoint) was also used in these analyses; only the results with the former definition are shown in this abstract, as the same conclusions were gained with both definitions. A treatment-specified subgroup detection tool (a resampling-based ensemble tree method) was used to identify predictors of response.

RESULTS

Of 1945 adults in the long-term analysis, 548 (28.2 %) were responders to atomoxetine at week 24; 65.2 % of 1397 non-responders had discontinued. Of 4524 adults in the short-term analysis, 1490 (32.9 %) were responders at week 10; 33.2 % of 1006 non-responders had discontinued. No analyzed baseline parameters (age, sex, prior stimulant use, ADHD subtype, CAARS-Inv:SV, CGI-S) were statistically significant predictors of response. Reductions in CAARS-Inv:SV total, CAARS-Inv:SV subscores, and CGI-S at week 4 in the short-term analysis, and at weeks 4 or 10 in the long-term analysis, were statistically significant predictors of response, i.e., patients with versus without these reductions early in treatment were more likely to be clinical responders at later time points. Sensitivity ranged from 28.6 to 85.9 %, and specificity ranged from 23.8 to 86.7 %. Predictors with higher sensitivity had lower specificity, and vice versa.

CONCLUSIONS

Reductions in CAARS-Inv:SV and CGI-S scores at weeks 4 and 10 are statistically significant predictors of response to atomoxetine at later time points in adults with ADHD. However, the predictors identified by these analyses are not reliable enough for use in clinical practice. The only currently available method to judge whether individuals with ADHD will respond to atomoxetine is to start treatment and assess the response over an extended period, sometimes longer than 10 weeks.

Attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHD) is a childhood-onset neurodevelopmental disorder with a prevalence of 1·4-3·0%. It is more common in boys than girls. Comorbidity with childhood-onset neurodevelopmental disorders and psychiatric disorders is substantial. ADHD is highly heritable and multifactorial; multiple genes and non-inherited factors contribute to the disorder. Prenatal and perinatal factors have been implicated as risks, but definite causes remain unknown. Most guidelines recommend a stepwise approach to treatment, beginning with non-drug interventions and then moving to pharmacological treatment in those most severely affected. Randomised controlled trials show short-term benefits of stimulant medication and atomoxetine. Meta-analyses of blinded trials of non-drug treatments have not yet proven the efficacy of such interventions. Longitudinal studies of ADHD show heightened risk of multiple mental health and social difficulties as well as premature mortality in adult life.

Atomoxetine Increased Effect over Time in Adults with Attention-Deficit/Hyperactivity Disorder Treated for up to 6 Months: Pooled Analysis of Two Double-Blind, Placebo-Controlled, Randomized Trials

Introduction

Changes in the magnitude of efficacy throughout 26 weeks of atomoxetine treatment, along with impact of dosing, were evaluated in adults with ADHD from two randomized, double‐blind, placebo‐controlled studies.

Aims

Pooled placebo (n = 485) and atomoxetine (n = 518) patients, dosed 25, 40, 60, 80 (target dose), or 100 mg daily, were assessed. Change from baseline in Conners’ Adult ADHD Rating Scale–Investigator Rated Scale: Screening Version (CAARS) total ADHD symptoms score and Adult ADHD Investigator Symptom Rating Scale (AISRS) total score were analyzed using mixed‐model repeated measures, with least squares mean change, effect size, and response rate calculated at 1, 2, 4, 8, 12, 16, 22, and 26 weeks.

Results

Decreases on CAARS for atomoxetine‐ versus placebo‐treated patients were consistently statistically significantly greater at every time point beginning at one week (P ≤ 0.006, 0.28 effect size). By 4 weeks, comparison was −13.19 compared with −8.84 (P < 0.0001, 0.45 effect size). By 26 weeks, mean change was −15.42 versus −9.71 (0.52 effect size); increase in effect size over time was most pronounced in the 80 mg group (0.82 effect size). AISRS demonstrated similar results. Atomoxetine response rate (CAARS 50% decrease) continued to increase throughout 26 weeks.

Conclusions

Atomoxetine treatment in adults with ADHD was associated with small effect sizes after 4 weeks and moderate effect sizes by 6 months of treatment. The data support increased effect size and response rate over time during longer‐term treatment at target dose.

Effects of atomoxetine on heart rhythm in children and adolescents

BACKGROUND

The aim of this study was to examine the effects of atomoxetine on heart rhythm using 12-lead electrocardiography (ECG) and 24 h Holter monitoring.

METHODS

Children and adolescents who were diagnosed with attention deficit-hyperactivity disorder according to DSM-IV-TR were referred to a pediatric cardiology clinic for cardiologic examination before and after 4 or 5 weeks of atomoxetine treatment. Cardiac examination, complete blood count, biochemistry, thyroid function tests, 12-lead ECG and 24 h Holter monitoring were performed routinely in all patients. Each subject underwent 24 h Holter ECG monitoring before atomoxetine was started and after 4 or 5 weeks of effective dose atomoxetine treatment.

RESULTS

Forty-one patients were included in this prospective study. No statistically significant change was found in QT, QTc or QT interval dispersion or blood pressure before and after 4 or 5 weeks of atomoxetine treatment. There was a statistically significant increase in heart rate (both during the day and at night) and QRS duration, and a statistically significant decrease in P wave dispersion. Three patients had rhythm disturbances. All of these three patients were asymptomatic and none of these arrhythmias reached clinical significance.

CONCLUSION

Atomoxetine did not cause significant changes in ECG or Holter variables. In two patients, who had undiagnosed subclinical extrasystoles, extra beats were increased after 4th week of treatment, but still remained clinically insignificant. Before and after atomoxetine treatment, listening to the heart sounds for a longer time, may help clinicians to notice an extra beat. If an extra beat is identified then 24 Holter monitoring is recommended.

Atomoxetine in patients with ADHD: A clinical and pharmacological review of the onset, trajectory, duration of response and implications for patients

This article reviews data providing new insight into the trajectory of response and maintenance of response of atomoxetine in the treatment of child and adult attention-deficit hyperactivity disorder (ADHD). This nonsystematic review includes: onset of action and duration of effect, response rate, effect size, time to optimal response and norepinephrine transporter blockade biomarker data. Atomoxetine can have an onset of action within 1-2 weeks of starting treatment, but there is an incrementally increasing response for up to 24 weeks or longer. Responder rates and effect sizes are similar to methylphenidate. Upon treatment discontinuation, relapse rates are lower than expected. In adults, 50% maintain their response for at least 6 months after stopping atomoxetine, following 6 months of treatment. Single-dose atomoxetine can provide 24-hour efficacy, despite a 5-hour plasma half-life. Hypotheses can be generated relating to neuroadaptive changes, to explain these findings. Atomoxetine has a trajectory of response that is incremental over a long period of time, with a greater than expected maintenance of response. This has implications for physician atomoxetine dosing and efficacy assessment, patient education and outcomes, and for clinical trial design and assessment of comparative efficacy with stimulant medications.

Atomoxetine treatment in adults with attention-deficit/hyperactivity disorder

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) is a CNS disorder that has its onset in childhood, but often persists into adulthood. There is growing recognition that adult ADHD can result in multiple negative consequences for individuals. ADHD is also often associated with a number of comorbid psychiatric disorders. Atomoxetine (ATX), a nonstimulant, selective noradrenergic reuptake inhibitor, was approved in the United States in 2002 for the treatment of ADHD in children and adolescents, as well as adults. We review here the safety and efficacy of ATX in adults with ADHD, including data in special populations, functional outcomes, as well as provider and patient real-world perceptions.

METHODS

We searched the databases Embase, MEDLINE and PsycINFO using the terms 'ADHD' and 'adult' and 'ATX' capturing publications from January 1, 1998, to March 27, 2014. Only publications in English were considered.

RESULTS

ATX demonstrated significantly greater improvement than placebo (PBO) on the Conners Adult ADHD Rating Scale-Investigator rated:Screening Version (CAARS-Inv:SV) in all trials (N = 6; total score difference ranged from -3.5 to -5.5). For long-term trials using the CAARS-Inv:SV, ATX demonstrated significantly greater improvement than PBO in three of four trials (total score differences ranged from -0.1 to -6.0). In short-term studies, ATX showed significantly greater improvement than PBO on the Adult ADHD Quality-of-Life scale total score in three of three studies, but results were mixed on the Sheehan Disability Scale. Three studies of ATX have reported statistically significant improvement (compared with PBO) on the Behavior Rating Inventory of Executive Function-Adult Version Self Report scale. The most common adverse events (occurring in ≥ 10% of patients taking ATX) were nausea, dry mouth, decreased appetite, insomnia and fatigue.

CONCLUSIONS

ATX is an important treatment option for the right patient. ATX can provide long-term, consistent symptom relief and functional improvement for adults with ADHD.

Impact of negative media publicity on attention-deficit/hyperactivity disorder medication in Taiwan

PURPOSE

This study explores trends in attention-deficit/hyperactivity disorder (ADHD) medications in Taiwan from 2000 to 2011 and whether negative media coverage of Ritalin in January 2010 impacted ADHD prescriptions throughout the country.

METHOD

Patients throughout Taiwan who had been newly diagnosed with ADHD (n = 145,269) between January 2000 and December 2011 were selected from Taiwan's National Health Insurance database as subjects for this study. We analyzed monthly and yearly data on person-days of treatment with immediate-release methylphenidate (IR-MPH), osmotic controlled-release formulation of methylphenidate (OROS-MPH), and atomoxetine (ATX) using linear models of curve estimation and the time series expert modeler.

RESULTS

Of our sample, 57.8%, 28.9%, and 4.3% had been prescribed one or more doses of IR-MPH, OROS-MPH, or ATX, respectively. The annual person-days of IR-MPH use increased regularly from 2000 to 2009, dropped abruptly in 2010, and then increased again the next year. Furthermore, the person-days of OROS-MPH prescriptions did not reach their expected goal in 2010; however, the person-days of ATX prescriptions have increased constantly since entering the market in 2007. Compared with patients newly diagnosed with ADHD in 2009, those newly diagnosed in 2010 were less likely to be treated with medication.

CONCLUSION

These findings suggest that negative publicity affected the writing of stimulant prescriptions for ADHD patients throughout Taiwan. Media reporting has a vital role in influencing children with ADHD, their parents, and their willingness to accept pharmacotherapy as treatment.

Patterns of long-term and short-term responses in adult patients with attention-deficit/hyperactivity disorder in a completer cohort of 12 weeks or more with atomoxetine

BACKGROUND

Atomoxetine is a well-established pharmacotherapy for adult ADHD. Long-term studies show incremental reductions in symptoms over time. However, clinical experience suggests that patients differ in their response patterns.

METHODS

From 13 Eli Lilly-sponsored studies, we pooled and analyzed data for adults with ADHD who completed atomoxetine treatment at long-term (24 weeks; n=1443) and/or short-term (12 weeks; n=2830) time-points, and had CAARS-Inv:SV total and CGI-S data up to or after these time-points and at Week 0 (i.e. at baseline, when patients first received atomoxetine). The goal was to identify and describe distinct trajectories of response to atomoxetine using hierarchical clustering methods and linear mixed modelling.

RESULTS

Based on the homogeneity of changes in CAARS-Inv:SV total scores, 5 response clusters were identified for patients who completed long-term (24 weeks) treatment with atomoxetine, and 4 clusters were identified for patients who completed short-term (12 weeks) treatment. Four of the 5 long-term clusters (comprising 95% of completer patients) showed positive trajectories: 2 faster responding clusters (L1 and L2), and 2 more gradually responding clusters (L3 and L4). Responses (i.e.≥30% reduction in CAARS-Inv:SV total score, and CGI-S score≤3) were observed at 8 and 24 weeks in 80% and 95% of completers in Cluster L1, versus 5% and 48% in Cluster L4.

CONCLUSIONS

While many adults with ADHD responded relatively rapidly to atomoxetine, others responded more gradually without a clear plateau at 24 weeks. Longer-term treatment may be associated with greater numbers of responders.

Real-World Dosing Patterns of Atomoxetine in Adults with Attention-Deficit/Hyperactivity Disorder

AIMS

The aim was to investigate the dosing patterns of atomoxetine monotherapy in adult patients with attention-deficit/hyperactivity disorder (ADHD) in a retrospective analysis.

METHODS

Adult (≥ 18 years) patients with ADHD newly initiated on atomoxetine with ≥ 1 outpatient pharmacy claim for atomoxetine between January 2006 and December 2011 were selected from the Truven Health MarketScan(®) Commercial database. After a 30-day titration period, dosing patterns of atomoxetine monotherapy were analyzed in the 12 months following initiation. In addition, patient demographic and clinical characteristics were compared to identify characteristics associated with suboptimal versus recommended dosing.

RESULTS

Of the 12,412 adult patients with ADHD newly initiated on atomoxetine, 4548 (36.6%) were suboptimally dosed, whereas 3323 (26.7%) were treated at recommended dose. Overall, study patients were treated at a mean (standard deviation [SD]) dose of 68.5 (44.9) mg/day. The suboptimal dosing cohort included significantly more females (54% vs. 44%, P < 0.001) and had fewer patients with pre-index use of other ADHD medications (17% vs. 20%, P < 0.001) compared with the recommended dosing cohort.

CONCLUSIONS

Adult patients with ADHD receiving atomoxetine therapy in a real-world setting are often dosed suboptimally. Increasing the awareness on optimal dosing strategy among clinicians and patients is warranted to maximize the therapeutic benefits of atomoxetine among adult patients with ADHD.

An Open-Label, Randomized Trial of Methylphenidate and Atomoxetine Treatment in Children with Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

The efficacy of both methylphenidate and atomoxetine has been established in placebo-controlled trials. The present study aimed to directly compare the efficacy of methylphenidate and atomoxetine in improving symptoms among children with attention-deficit/hyperactivity disorder (ADHD).

METHODS

The study sample included 160 drug-naïve children and adolescents 7-16 years of age, with DSM-IV-defined ADHD, randomly assigned to osmotic-release oral system methylphenidate (OROS-methylphenidate) (n=80) and atomoxetine (n=80) in a 24 week, open-label, head-to-head clinical trial. The primary efficacy measure was the score of the ADHD Rating Scale-IV Parents Version: Investigator Administered and Scored (ADHD-RS-IV). The secondary efficacy measures included the Clinical Global Impressions-ADHD-Severity (CGI-ADHD-S) and Chinese Swanson, Nolan, and Pelham IV scale (SNAP-IV), based on the ratings of investigators, parents, teachers, and subjects.

RESULTS

At week 24, mean changes in ADHD-RS-IV Inattention scores were 13.58 points (Cohen's d, -3.08) for OROS-methylphenidate and 12.65 points (Cohen's d, -3.05) for atomoxetine; and mean changes in ADHD-RS-IV Hyperactivity-Impulsivity scores were 10.16 points (Cohen's d, -1.75) for OROS-methylphenidate and 10.68 points (Cohen's d, -1.87) for atomoxetine. In terms of parent-, teacher-, and self-ratings on behavioral symptoms, both of the two treatment groups significantly decreased on the SNAP-IV scores at the end-point, with effect sizes ranging from 0.9 to 0.96 on the Inattention subscale and from 0.61 to 0.8 on the Hyperactivity/Impulsivity subscale for OROS-methylphenidate; and from 0.51 to 0.88 on the Inattention subscale and from 0.29 to 0.57 on the Hyperactivity/Impulsivity subscale for atomoxetine. No statistically significant differences between treatment groups were observed on the outcome measures. Vomiting, somnolence, and dizziness were reported more often for atomoxetine than for OROS-methylphenidate, whereas insomnia was reported more often for OROS-methylphenidate than for atomoxetine.

CONCLUSIONS

After 24 weeks of treatment, OROS-methylphenidate and atomoxetine had comparable efficacy in reducing core ADHD symptoms in drug-naïve children and adolescents with ADHD.

Atomoxetine pharmacogenetics: associations with pharmacokinetics, treatment response and tolerability

Atomoxetine is indicated for the treatment of attention deficit hyperactivity disorder and is predominantly metabolized by the CYP2D6 enzyme. Differences in pharmacokinetic parameters as well as clinical treatment outcomes across CYP2D6 genotype groups have resulted in dosing recommendations within the product label, but clinical studies supporting the use of genotype guided dosing are currently lacking. Furthermore, pharmacokinetic and clinical studies have primarily focused on extensive as compared with poor metabolizers, with little information known about other metabolizer categories as well as genes involved in the pharmacodynamics of atomoxetine. This review describes the pharmacogenetic associations with atomoxetine pharmacokinetics, treatment response and tolerability with considerations for the clinical utility of this information.

Subchronic administration of atomoxetine causes an enduring reduction in context-induced relapse to cocaine seeking without affecting impulsive decision making

Previous work has established a robust relationship between impulsivity and addiction, and revealed that impulsive decision making predisposes the vulnerability to cocaine-seeking behavior in rats. An important next step is to assess whether elevated relapse vulnerability can be treated via the reduction of impulsive decision making. Therefore, this study explored whether subchronic atomoxetine treatment can reduce relapse vulnerability by reducing impulsive decision making. Rats were trained in the delayed reward task and were subjected to 3 weeks of cocaine self-administration. Following drug self-administration, animals were divided to different experimental groups and received the noradrenaline transporter inhibitor and attention-deficit/hyperactivity disorder drug atomoxetine or vehicle subchronically for 20 days. On days 1 and 10 after treatment cessation, a context-induced reinstatement test was performed. Throughout the entire experiment, changes in impulsive decision making were continuously monitored. Subchronic treatment with atomoxetine reduced context-induced reinstatement both 1 and 10 days after treatment cessation, only in animals receiving no extinction training. Interestingly, neither subchronic nor acute atomoxetine treatments affected impulsive decision making. Our data indicate that the enduring reduction in relapse sensitivity by atomoxetine occurred independent of a reduction in impulsive decision making. Nonetheless, repeated atomoxetine administration seems a promising pharmacotherapeutical strategy to prevent relapse to cocaine seeking in abstinent drug-dependent subjects.

Psychostimulants and atomoxetine alter the electrophysiological activity of prefrontal cortex neurons, interaction with catecholamine and glutamate NMDA receptors

RATIONALE

Attention-deficit hyperactivity disorder (ADHD) is the most frequently diagnosed neuropsychiatric disorder in childhood. Currently available ADHD drugs include the psychostimulants methylphenidate (MPH) and D-amphetamine (D-AMP), acting on norepinephrine and dopamine transporters/release, and atomoxetine (ATX), a selective norepinephrine uptake inhibitor. Recent evidence suggests an involvement of glutamate neurotransmission in the pathology and treatment of ADHD, via mechanisms to be clarified.

OBJECTIVE

We have investigated how ADHD drugs could modulate, through interaction with catecholamine receptors, basal and glutamate-induced excitability of pyramidal neurons in the prefrontal cortex (PFC), a region which plays a major role in control of attention and impulsivity.

METHODS

We have used the technique of extracellular single-unit recording in anaesthetised rats coupled with microiontophoresis.

RESULTS

Both MPH (1-3 mg/kg) and D-AMP (1-9 mg/kg) increased the firing activity of PFC neurons in a dopamine D1 receptor-dependent manner. ATX administration (1-6 mg/kg) also increased the firing of neurons, but this effect is not significantly reversed by D1 (SCH 23390) or alpha1 (prazosin) receptor antagonists but potentiated by alpha2 antagonist (yohimbine). All drugs induced a clear potentiation of the excitatory response of PFC neurons to the microiontophoretic application of the glutamate agonist N-methyl-D-aspartate (NMDA), but not to the glutamate agonist α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA). The potentiating effect of D-AMP on NMDA-induced activation of PFC neurons was partially reversed or prevented by dopamine D1 receptor blockade.

CONCLUSION

Our data shows that increase in excitability of PFC neurons in basal conditions and via NMDA receptor activation may be involved in the therapeutic response to ADHD drugs.

[Attention deficit hyperactivity disorder]

Attention deficit hyperactivity disorder (ADHD) is one of the most common childhood psychiatric disorders and can persist into the adulthood. ADHD has important social, academic and occupational consequences. ADHD diagnosis is based on the fulfillment of several clinical criteria, which can vary depending on the diagnostic system used. The clinical presentation can show great between-patient variability and it has been related to a dysfunction in the fronto-striatal and meso-limbic circuits. Recent investigations support a model in which multiple genetic and environmental factors interact to create a neurobiological susceptibility to develop the disorder. However, no clear causal association has yet been identified. Although multimodal treatment including both pharmacological and psychosocial interventions is usually recommended, no convincing evidence exists to support this recommendation. Pharmacological treatment has fundamentally shown to improve ADHD symptoms in the short term, while efficacy data for psychosocial interventions are scarce and inconsistent. Yet, drug treatment is increasingly popular and the last 2 decades have witnessed a sharp increase in the prescription of anti-ADHD medications coinciding with the marketing of new drugs to treat ADHD.

The efficacy of atomoxetine for the treatment of children and adolescents with attention-deficit/hyperactivity disorder: a comprehensive review of over a decade of clinical research

Atomoxetine was first licensed to treat attention-deficit/hyperactivity disorder (ADHD) in children and adolescents in the US in 2002. The aim of this paper is to comprehensively review subsequent publications addressing the efficacy of atomoxetine in 6- to 18-year-olds with ADHD. We identified 125 eligible papers using a predefined search strategy. Overall, these papers demonstrate that atomoxetine is an effective treatment for the core ADHD symptoms (effect sizes 0.6-1.3, vs. placebo, at 6-18 weeks), and improves functional outcomes and quality of life, in various pediatric populations with ADHD (i.e., males/females, patients with co-morbidities, children/adolescents, and with/without prior exposure to other ADHD medications). Initial responses to atomoxetine may be apparent within 1 week of treatment, but can take longer (median 23 days in a 6-week study; n=72). Responses often build gradually over time, and may not be robust until after 3 months. A pooled analysis of six randomized placebo-controlled trials (n=618) indicated that responses at 4 weeks may predict response at 6-9 weeks, although another pooled analysis of open-label data (n=338) suggests that the probability of a robust response to atomoxetine [≥40% decrease in ADHD-Rating Scale (ADHD-RS) scores] may continue to increase beyond 6-9 weeks. Atomoxetine may demonstrate similar efficacy to methylphenidate, particularly immediate-release methylphenidate, although randomized controlled trials are generally limited by short durations (3-12 weeks). In conclusion, notwithstanding these positive findings, before initiating treatment with atomoxetine, it is important that the clinician sets appropriate expectations for the patient and their family with regard to the likelihood of a gradual response, which often builds over time.

Attention benefits after a single dose of metadoxine extended release in adults with predominantly inattentive ADHD

OBJECTIVE

To assess the first-dose effectiveness and tolerability of metadoxine extended release (MDX) in adults with predominantly inattentive attention-deficit/hyperactivity disorder (ADHD-PI).

METHODS

In this double-blind, placebo-controlled, crossover study, adults with ADHD-PI were randomized 1:1:1 to receive a single dose of MDX 1400 mg, MDX 700 mg, and placebo (ClinicalTrials.gov identifier: NCT01685281). The primary efficacy end point was the mean change in the Test of Variables of Attention (TOVA) ADHD score from baseline to 3 to 5 hours after drug administration. Secondary assessments included TOVA subscores, TOVA response rates (defined as an increase of 0.8 points in the TOVA ADHD score), and the Cambridge Neuropsychological Automated Test Battery. Safety assessments included adverse events and vital signs.

RESULTS

The intention-to-treat population included 36 patients (52.8% men; mean age, 32 years). The efficacy of MDX 1400 mg was demonstrated by a statistically significant difference in the mean (± SD) change in the TOVA ADHD score at baseline to 3 to 5 hours after drug administration compared with placebo (2.0 [4.2]; P = 0.009). The TOVA response time variability subscore was significantly different between MDX 1400 mg and placebo (mean difference, 7.9 [19.2] points; P = 0.022). Significantly more adults responded to single-dose MDX 1400 mg versus placebo (97.1% vs 71.4%, P = 0.006). There were no statistically significant differences between MDX 700 mg and placebo on any measures. Exploratory analyses of the Cambridge Neuropsychological Automated Test Battery did not yield significant findings. Fatigue and headache were the 2 most frequently reported adverse events. There were no clinically significant abnormalities in laboratory values, vital signs measurements, Columbia-Suicide Severity Rating Scale scores, or electrocardiographic parameters.

CONCLUSIONS

Single-dose MDX 1400 mg significantly improved sustained and selective attention in adults with ADHD-PI as measured by the TOVA ADHD score 3 to 5 hours after drug administration. Single doses of MDX 700 and 1400 mg were well tolerated.

Efficacy and safety of extended-release guanfacine hydrochloride in children and adolescents with attention-deficit/hyperactivity disorder: a randomized, controlled, phase III trial

Guanfacine extended-release (GXR), a selective α2A-adrenergic agonist, is a non-stimulant treatment for attention-deficit/hyperactivity disorder (ADHD). This study assessed the efficacy (symptoms and function) and safety of dose-optimized GXR compared with placebo in children and adolescents with ADHD. An atomoxetine (ATX) arm was included to provide reference data against placebo. Patients (6-17 years) were randomized at baseline to dose-optimized GXR (0.05-0.12mg/kg/day - 6-12 years: 1-4mg/day; 13-17 years: 1-7mg/day), ATX (10-100mg/day) or placebo for 4 or 7 weeks. The primary efficacy measure was change from baseline in ADHD Rating Scale version IV (ADHD-RS-IV). Key secondary measures were Clinical Global Impression-Improvement (CGI-I) and the Weiss Functional Impairment Rating Scale-Parent Report (WFIRS-P; learning and school, and family domains). Safety assessments included treatment-emergent adverse events (TEAEs), electrocardiograms and vital signs. A total of 272 (80.5%) patients from Europe, the USA and Canada completed the study. Significant differences were observed in least squares mean change from baseline in ADHD-RS-IV total score (placebo-adjusted differences) (GXR: [-8.9, p<0.001]; ATX: [-3.8, p<0.05]), the difference from placebo in the percentage of patients showing improvement (1 ['very much improved'] or 2 ['much improved']) for CGI-I (GXR: [23.7, p<0.001]; ATX: [12.1, p<0.05]), WFIRS-P learning and school domain (GXR: [-0.22, p<0.01]; ATX: [-0.16, p<0.05]) and WFIRS-P family domain (GXR: [-0.21, p<0.01]; ATX: [-0.09, p=0.242]). Most common TEAEs for GXR were somnolence, headache and fatigue; 70.1% of GXR subjects reported mild-to-moderate TEAEs. GXR was effective and well tolerated in children and adolescents with ADHD.

Managing the risks of ADHD treatments

Pharmacotherapy of attention deficit-hyperactivity disorder (ADHD) is a well-established and effective treatment modality. However, ADHD medications are not without side effects. Understanding the prevalence of adverse events and effective management of risks associated with stimulants and other medications used to treat ADHD is central to broad applicability and effective treatment. This review discusses the literature on the prevalence of adverse events and management strategies employed. We searched online MEDLINE/PubMed and Cochrane databases for articles using several keywords relating to adverse events associated with ADHD medication management. We discuss the relevant data on the significance and prevalence of side effects and adverse events, highlight recent updates in the field, and suggest approaches to clinical management.

Pharmacological interventions for adolescents and adults with ADHD: stimulant and nonstimulant medications and misuse of prescription stimulants

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by symptoms of inattention, hyperactivity, and impulsivity that cause functional impairment. Recent research indicates that symptoms persist into adulthood in the majority of cases, with prevalence estimates of approximately 5% in the school age population and 2.5%–4% in the adult population. Although students with ADHD are at greater risk for academic underachievement and psychosocial problems, increasing numbers of students with ADHD are graduating from high school and pursuing higher education. Stimulant medications are considered the first line of pharmacotherapy for individuals with ADHD, including college students. Although preliminary evidence indicates that prescription stimulants are safe and effective for college students with ADHD when used as prescribed, very few controlled studies have been conducted concerning the efficacy of prescription stimulants with college students. In addition, misuse of prescription stimulants has become a serious problem on college campuses across the US and has been recently documented in other countries as well. The purpose of the present systematic review was to investigate the efficacy of prescription stimulants for adolescents and young adults with ADHD and the nonmedical use and misuse of prescription stimulants. Results revealed that both prostimulant and stimulant medications, including lisdexamfetamine dimesylate, methylphenidate, amphetamines, and mixed-amphetamine salts, are effective at reducing ADHD symptoms in adolescents and adults with ADHD. Findings also suggest that individuals with ADHD may have higher rates of stimulant misuse than individuals without the disorder, and characteristics such as sex, race, use of illicit drugs, and academic performance are associated with misuse of stimulant medications. Results also indicate that individuals both with and without ADHD are more likely to misuse short-acting agents than long-acting agents. These findings have implications for intervention, prevention, and future research.