A community assessment, open-label study of the safety, tolerability, and effectiveness of mixed amphetamine salts extended release in school-age children with ADHD

A review of amphetamine extended release once-daily options for the management of attention-deficit hyperactivity disorder

INTRODUCTION

Amphetamine preparations are one of the two categories of stimulant medications approved for the treatment of attention deficit hyperactivity disorder (ADHD). Optimal treatment of ADHD aims to reduce core symptoms for as much of the waking hours as possible, leading to longer-acting delivery formats. In addition, the pediatric population commonly has difficulty swallowing pills and manufacturers have developed a variety of options to facilitate this concern. These include chewable tablets, capsules that may be sprinkled on soft food, liquids and transdermal patches.

AREAS COVERED

This article reviews the once-daily extended-release preparations currently available for amphetamine compounds, their pharmacodynamics, and common adverse effects.

EXPERT OPINION

There is an extensive evidence base supporting use of amphetamine preparations in the treatment of ADHD. Rapid onset of action and a favorable side effect profile make these widely used. The availability of once-daily extended-release chewable tablets, capsules that can be opened and sprinkled, and liquid formulations provides clinicians with multiple options to meet the specific needs of patients with difficulty swallowing whole pills.

A long-term open-label safety and effectiveness trial of lisdexamfetamine dimesylate in adolescents with attention-deficit/hyperactivity disorder

OBJECTIVE

Information on psychostimulant treatment in long-term studies for attention-deficit/hyperactivity disorder (ADHD) in adolescents is limited. This study aimed to assess the safety and effectiveness of lisdexamfetamine dimesylate (LDX) over 52 weeks in adolescents with ADHD.

METHODS

This open-label multicenter study enrolled eligible participants after their participation in a randomized, double-blind, placebo-controlled 4 week trial in adolescents with ADHD. Following a 4 week dose-optimization phase, participants were maintained on treatment for up to ∼48 weeks on an optimal dose. Safety assessments included treatment-emergent adverse events (TEAEs), vital signs, laboratory findings, and electrocardiograms. Effectiveness measures included the ADHD Rating Scale IV (ADHD-RS-IV; primary) and Clinical Global Impressions-Improvement (CGI-I). The Youth Quality of Life-Research Version (YQOL-R) was also included in this study; raw scores are transformed to a 0-100 point scale.

RESULTS

Of 269 enrolled (from the antecedent study), 265 (98.5%) were in the safety population and effectiveness population. Common TEAEs (≥5%) with LDX included upper respiratory tract infection (21.9%), decreased appetite (21.1%), headache (20.8%), decreased weight (16.2%), irritability (12.5%), insomnia (12.1%), nasopharyngitis (7.2%), influenza (6.8%), dizziness (5.3%), and dry mouth (5.3%). At end point, for all LDX doses in the overall safety population, mean (SD) increase from baseline in systolic blood pressure was 2.3 (10.53) mm Hg, diastolic blood pressure was 2.5 (8.37) mm Hg, and pulse rate was 6.3 (12.74) bpm. No clinically meaningful electrocardiogram or vital sign changes were observed. At end point with LDX treatment, the ADHD-RS-IV mean (SD) total score change from antecedent study baseline was -26.2 (9.75) (p<0.001); 87.2% of participants were improved (CGI-I=1 or 2). Baseline (antecedent study) mean (SD) YQOL-R perceptual total score was 79.8 (11.28) and increased by 3.9 (9.73) at end point (p<0.001).

CONCLUSIONS

LDX demonstrated a long-term safety profile similar to that of other long-acting psychostimulants and was effective, as indicated by improvements in ADHD symptoms and participant-perceived YQOL, in adolescents with ADHD.

CLINICAL TRIAL REGISTRATION

NCT00764868, http://www.clinicaltrials.gov/ct2/show/NCT00764868?term=SPD489-306&rank=1.

The pharmacology and clinical outcomes of amphetamines to treat ADHD: does composition matter?

Attention-deficit hyperactivity disorder (ADHD) treatment options include pharmacological and nonpharmacological approaches. In North America, psychostimulants (amphetamine and methylphenidate) are considered first-line pharmacological treatments for patients (children, adolescents and adults) with ADHD. However, in the UK, National Institute for Health and Clinical Excellence (NICE) guidelines have placed short-acting d-amphetamine as a third-line treatment option due to a lack of contemporary, published clinical trials on its efficacy and the concerns from clinical and patient experts regarding the potential for increased abuse and/or misuse compared with methylphenidate. These guidelines do not account for some of the more recent amphetamine products that have been developed to alleviate some of these concerns, but that are not currently approved in the UK or other European countries. The purpose of this review is to describe the pharmacology and clinical efficacy of various amphetamine compositions, as well as to explore the apparent differences in these compositions and their associated risks and benefits. A PubMed literature search was conducted to investigate amphetamine pharmacology, clinical efficacy and safety and ADHD outcomes in the published literature from 1980 through March 2011. Search terms included the keywords 'ADHD' or 'ADD' or 'hyperkinetic disorder' and any of the following keywords combined with 'or': 'amphetamine', 'dexamphetamine', 'mixed amphetamine salts', 'lisdexamfetamine' and 'methamphetamine'. The search included English-language primary research articles and review articles but excluded editorial articles and commentaries. The literature search resulted in 330 articles. Pertinent articles relating to amphetamine pharmacology, compositions, clinical efficacy and safety, effectiveness and tolerability, ADHD outcomes and abuse liability were included in this review. The different delivery profiles of amphetamine compositions result in pharmacological and pharmacokinetic differences that contribute to varying effects in the clinical treatment of ADHD, ADHD outcomes and abuse liability. The efficacy and safety of amphetamine compositions for the treatment of ADHD have been demonstrated in clinical trials and meta-analyses, and the long-acting amphetamine compositions have been widely studied and found efficacious without increased adverse effects. Long-acting amphetamine compositions offer the obvious advantage of enhanced duration of action over short-acting amphetamine compositions, and lisdexamfetamine has been shown to have reduced abuse liability compared with short-acting amphetamine.

Efficacy and safety of lisdexamfetamine dimesylate in adolescents with attention-deficit/hyperactivity disorder

OBJECTIVE

To examine lisdexamfetamine dimesylate (LDX) efficacy and safety versus placebo in adolescents with attention-deficit/hyperactivity disorder (ADHD).

METHOD

Adolescents (13 through 17) with at least moderately symptomatic ADHD (ADHD Rating Scale IV: Clinician Version [ADHD-RS-IV] score ≥28) were randomized to placebo or LDX (30, 50, or 70 mg/d) in a 4-week, forced-dose titration, double-blind study. Primary and secondary efficacy measures were the ADHD-RS-IV, Clinical Global Impressions-Improvement (CGI-I), and Youth QOL-Research Version (YQOL-R). Safety assessments included treatment-emergent adverse events (TEAEs), vital signs, laboratory findings, physical examinations, and ECG.

RESULTS

Overall, 314 participants were randomized; 309 were in efficacy analyses and 49 withdrew (11 due to TEAEs). Least squares mean (SE) change from baseline at endpoint in ADHD-RS-IV total scores were -18.3 (1.25), -21.1 (1.28), -20.7 (1.25) for 30, 50, and 70 mg/d LDX, respectively; -12.8 (1.25) for placebo (p ≤ .0056 versus placebo for each). Differences in ADHD-RS-IV total scores favored all LDX doses versus placebo at all weeks (p ≤ .0076). On the CGI-I, 69.1% of participants were rated very much/much improved at endpoint with LDX all doses versus placebo (39.5%) (p < .0001). YQOL-R changes at endpoint scores for LDX groups versus placebo were not significant. Commonly reported LDX (all doses combined) TEAEs (≥5%) were decreased appetite, headache, insomnia, decreased weight, and irritability. Small mean increases in pulse and blood pressure and no clinically meaningful trends in ECG changes were noted with LDX.

CONCLUSIONS

LDX at all doses was effective versus placebo in treating adolescent ADHD and demonstrated a safety profile consistent with previous LDX studies. CLINICAL TRIALS REGISTRY INFORMATION: Efficacy and Safety of Lisdexamfetamine Dimesylate (LDX) in Adolescents With Attention-Deficit/Hyperactivity Disorder (ADHD); http://www.clinicaltrials.gov; NCT00735371.

Prevalence and patterns of methylphenidate use in French children and adolescents

OBJECTIVE

The aim of the study was to describe the prevalence and utilization patterns of methylphenidate (MPH) in children and adolescents in France.

METHODS

This was a population-based retrospective study in which the cohort consisted of patients for whom data were extracted from the dispensation drug claims database of the national health insurance (NHI) fund for self-employed workers. Annual prevalence of MPH use was evaluated on patients aged 6-18 years who were reimbursed for at least one MPH prescription a year. Between January 2004 and June 2005, features of MPH medication and user profile were described for the "new starters" having a screening period of 1 year without receiving a MPH prescription and a follow-up >or=12 months. Time to interruption of MPH regular use was analysed by Kaplan-Meier survival analysis. Mean duration of exposure to MPH treatment was computed with the 95% confidence interval (CI).

RESULTS

Annual prevalence of MPH per 1000 persons was 1.1 in 2003, 1.5 in 2004 and 1.8 in 2005 (relative increase of 63.5%). New starters (n = 447) received their first MPH prescription through the hospital (65.1%) or through private practitioners (34.9%). The user profiles were: short (16.6%), occasional (33.8%) and regular (49.6%). Among the new starters, the median time to interruption of MPH regular use was 10.2 months (95% CI: 7.9-12.4). The mean duration of exposure to MPH treatment was: occasional (4.9 months, 95% CI: 4.3-5.5) and regular (25.7 months, 95% CI: 24.6-26.8).

CONCLUSION

Although there is a low prevalence of MPH use in France, this survey revealed a wide profile of users and heterogeneous use patterns.

Cardiovascular effects of mixed amphetamine salts extended release in the treatment of school-aged children with attention-deficit/hyperactivity disorder

BACKGROUND

The cardiovascular safety of mixed amphetamine salts extended release (MAS XR) was evaluated in 2968 children 6-12 years of age with attention-deficit/hyperactivity disorder (ADHD).

METHODS

In this prospective, open-label, noncomparative, community-based study, subjects whose symptoms of ADHD were well controlled with stimulant medication maintained their established treatment regimens for 2 weeks before enrollment into the current study. Subjects' regimens were then converted to an approximately equivalent once-daily dose of MAS XR 10, 20, or 30 mg/d according to a medication-conversion algorithm, which could be adjusted to 40 mg/d for optimal efficacy and tolerability. Systolic blood pressure (SBP), diastolic BP (DBP), and pulse were measured at each study visit. Twelve-lead electrocardiography was performed at screening and at the end of the extension phase or early termination.

RESULTS

No clinically significant changes in BP or pulse were observed. Although one subject experienced a QT-prolongation interval > 25%, no clinically significant prolongation in the mean QT interval was seen. Approximately 2.5% of subjects demonstrated two consecutive SBP or DBP values > 95th percentile for age, sex, and height, and 3.6% of subjects' pulse increased by > or = 25 to > or = 110 beats per minute. No serious cardiovascular adverse events or deaths occurred.

CONCLUSIONS

In addition to demonstrated efficacy and safety, the cardiovascular profile of MAS XR showed generally small divergences from age-specific population norms that pose very limited risk in this patient population.