Pharmacokinetic considerations in the treatment of attention-deficit hyperactivity disorder with methylphenidate

Learning and memory deficits produced by aspartame are heritable via the paternal lineage

Environmental exposures produce heritable traits that can linger in the population for one or two generations. Millions of individuals consume substances such as artificial sweeteners daily that are declared safe by regulatory agencies without evaluation of their potential heritable effects. We show that consumption of aspartame, an FDA-approved artificial sweetener, daily for up to 16-weeks at doses equivalent to only 7-15% of the FDA recommended maximum daily intake value (equivalent to 2-4 small, 8 oz diet soda drinks per day) produces significant spatial learning and memory deficits in mice. Moreover, the cognitive deficits are transmitted to male and female descendants along the paternal lineage suggesting that aspartame's adverse cognitive effects are heritable, and that they are more pervasive than current estimates, which consider effects in the directly exposed individuals only. Traditionally, deleterious environmental exposures of pregnant and nursing women are viewed as risk factors for the health of future generations. Environmental exposures of men are not considered to pose similar risks. Our findings suggest that environmental exposures of men can produce adverse impact on cognitive function in future generations and demonstrate the need for considering heritable effects via the paternal lineage as part of the regulatory evaluations of artificial sweeteners.

Methylphenidate for attention-deficit/hyperactivity disorder in adults: a narrative review

RATIONALE

Psychostimulants, including methylphenidate (MPH), are the mainstay of pharmacotherapy for attention-deficit/hyperactivity disorder (ADHD) in adults. Even though MPH is the most commonly used medication for ADHD these days, there are relatively few resources available that provide comprehensive insight into the pharmacological and clinical features of the compound.

OBJECTIVE

The aim of this paper is to provide an up-to-date outline of the pharmacology and clinical utility of MPH for ADHD in adult patients.

METHODS

While conducting the narrative review, we applied structured search strategies covering the two major online databases (MEDLINE and Cochrane Central Register of Controlled Trials). In addition, we performed handsearching of reference lists of relevant papers.

RESULTS

Methylphenidate exhibits multimodal mechanism of action, working primarily as a dopamine and noradrenaline reuptake inhibitor. It also protects the dopaminergic system against the ongoing 'wearing off' (by securing a substantial reserve pool of the neurotransmitter, stored in the presynaptic vesicles). In placebo-controlled trials, MPH was shown to be moderately effective both against the core ADHD symptoms (standardized mean difference [SMD], 0.49; 95% confidence interval [CI], 0.35-0.64), and the accompanying emotion regulation deficits (SMD, 0.34; 95% CI, 0.23-0.45). The most common adverse events related to long-term treatment with MPH are decreased appetite (~ 20%), dry mouth (15%), heart palpitations (13%), gastrointestinal infections (~ 10%), and agitation/feeling restless (~ 10%).

CONCLUSIONS

There is substantial body of evidence to suggest that MPH is an effective and safe treatment option for adults with ADHD.

Methylphenidate for attention problems in epilepsy patients: Safety and efficacy

Children with attention deficit hyperactivity disorder (ADHD) have an increased risk of seizures, and children with epilepsy have an increased prevalence of ADHD. Adults with epilepsy often have varying degrees of attentional dysfunction due to multiple factors, including anti-seizure medications, frequent seizures, interictal discharges, underlying lesions, and psychiatric comorbidities. Currently, there are no approved medications for the treatment of epilepsy-related attentional dysfunction. Methylphenidate (MPH) is a stimulant, FDA-approved for the treatment of ADHD, and often used for ADHD in the setting of pediatric epilepsy. Large database and registry studies indicate safety of MPH in children with ADHD and epilepsy, with no significant effect on seizure frequency. Small single-dose and open-label studies suggest efficacy of MPH in adults with epilepsy-related attention deficits. Methylphenidate represents a possible treatment for attentional dysfunction due to epilepsy, but large, randomized, placebo-controlled, double-blinded studies are needed.

Clinically Significant Drug-Drug Interactions with Agents for Attention-Deficit/Hyperactivity Disorder

This article provides an overview of the pharmacokinetic drug-drug interactions (DDIs) for agents prescribed for attention-deficit/hyperactivity disorder (ADHD). Polypharmacy in the treatment of patients with ADHD leads to high exposures to DDIs and possibly adverse safety outcomes. We performed a systematic search of DDI reports for ADHD agents in Embase and Medline. We also searched for agents in the pharmacological pipeline, which include (1) mazindol, molindone and viloxazine, which were previously prescribed for other indications; (2) centanafadine and AR-08, never before approved; and (3) two extracts (Polygala tenuifolia extract and the French maritime pine bark extracts). The identified literature included case reports, cross-sectional, cross-over and placebo-controlled studies of patient cohorts and healthy volunteers. The DDIs were classified as follows: ADHD agents acting as perpetrators, i.e., affecting the clearance of co-prescribed agents (victim drugs), or ADHD agents being the victim drugs, being affected by other agents. Ratios for changes in pharmacokinetic parameters before and after the DDI were used as a rough estimate of the extent of the DDI. Alcohol may increase plasma dextroamphetamine concentrations by presystemic effects. Until studies are done to orient clinicians regarding dosing changes, clinicians need to be aware of the potential for cytochrome P450 (CYP) 2D6 inhibitors to increase amphetamine levels, which is equivalent to increasing dosages. Atomoxetine is a wide therapeutic window drug. The CYP2D6 poor metabolizers who do not have CYP2D6 activity had better atomoxetine response, but also an increased risk of adverse effects. CYP2D6 inhibitors have been used to increase atomoxetine response in CYP2D6 extensive metabolizers. Guanfacine is mainly metabolized by CYP3A4, which can be induced and inhibited. The package insert recommends that in guanfacine-treated patients, after adding potent CYP3A4 inducers, the guanfacine dose should be doubled; after adding potent CYP3A4 inhibitors the guanfacine dose should be halved. Based on a phenobarbital case report and our experience with CYP3A4-metabolized antipsychotics, these correction factors may be too low. According to two case reports, carbamazepine is a clinically relevant inducer of methylphenidate (MPH). A case series study suggested that MPH may be associated with important elevations in imipramine concentrations. Due to the absence of or limitations in the data, no comments for clinicians can be provided on the pharmacokinetic DDIs for clonidine, centanafadine, mazindol, molindone, AR-08, P. tenuifolia extract and the French maritime pine bark extracts. According to currently available data, clinicians should not expect that ADHD drugs modify each other's serum concentrations. A summary table for clinicians provides our current recommendations on pharmacokinetic DDIs of ADHD agents based on our literature review and the package inserts; whenever it was possible, we provide information on serum concentrations and dose correction factors. There will be a need to periodically update these recommendations and these correction factors as new knowledge becomes available.

An update on the pharmacokinetic considerations in the treatment of ADHD with long-acting methylphenidate and amphetamine formulations

Introduction: Long-acting stimulant formulations are recommended as first-line pharmacotherapy for attention-deficit/hyperactivity disorder (ADHD). Over the past 20 years, extended-release (ER) methylphenidate (MPH) and amphetamine (AMP) formulations have evolved to include varying drug delivery technologies, enantiomers/salts, and dosage forms. All formulations are characterized by a unique pharmacokinetic profile that is closely mirrored by pharmacodynamic response allowing clinicians to individualize therapy based on their patient's clinical needs and dosing preferences.Areas covered: This review provides an update on the pharmacokinetic properties of approved and investigational ER MPH and AMP formulations and highlights pharmacokinetic features that clinicians should consider when selecting a long-acting stimulant.Expert opinion: Since there are no reliable biomarkers that can predict individualized response to long-acting stimulants, clinicians need to consider their distinctive pharmacokinetic properties, including the pharmacokinetic profile, rate and extent of absorption, variability, dose proportionality, bioequivalence, and potential for accumulation. Clinicians also need to understand that certain factors can contribute to increased variability in pharmacokinetics and potentially affect outcomes. Less invasive, high-throughput techniques and novel time-based scales are being developed to advance research on the pharmacokinetic-pharmacodynamic relationships of stimulants. Model-based pharmacokinetic-pharmacodynamic approaches can be applied to aid the development of novel formulations and individualize therapy with existing drugs.

Drug-drug interactions and clinical considerations with co-administration of antiretrovirals and psychotropic drugs

Psychotropic medications are frequently co-prescribed with antiretroviral therapy (ART), owing to a high prevalence of psychiatric illness within the population living with HIV, as well as a 7-fold increased risk of HIV infection among patients with psychiatric illness. While ART has been notoriously associated with a multitude of pharmacokinetic drug interactions involving the cytochrome P450 enzyme system, the magnitude and clinical impact of these interactions with psychotropics may range from negligible effects on plasma concentrations to life-threatening torsades de pointes or respiratory depression. This comprehensive review summarizes the currently available information regarding drug-drug interactions between antiretrovirals and pharmacologic agents utilized in the treatment of psychiatric disorders-antidepressants, stimulants, antipsychotics, anxiolytics, mood stabilizers, and treatments for opioid use disorder and alcohol use disorder-and provides recommendations for their management. Additionally, overlapping toxicities between antiretrovirals and the psychotropic classes are highlighted. Knowledge of the interaction and adverse effect potential of specific antiretrovirals and psychotropics will allow clinicians to make informed prescribing decisions to better promote the health and wellness of this high-risk population.

Methodological advantages and disadvantages of parallel and crossover randomised clinical trials on methylphenidate for attention deficit hyperactivity disorder: a systematic review and meta-analyses

OBJECTIVE

To assess the methodological advantages and disadvantages of parallel and crossover designs in randomised clinical trials on methylphenidate for children and adolescents with attention deficit hyperactivity disorder (ADHD).

DESIGN

Secondary analyses of a Cochrane systematic review.

SETTING AND PARTICIPANTS

We searched relevant databases up to March 2015 and included data from parallel and crossover randomised trials assessing children and adolescents up to 18 years with ADHD.

INTERVENTIONS

Methylphenidate compared with placebo or no-treatment interventions.

PRIMARY AND SECONDARY OUTCOMES

The primary outcomes were teacher-rated ADHD symptoms and serious adverse events. The secondary outcomes were non-serious adverse events.

RESULTS

We included 38 parallel trials (n=5111) and 147 crossover trials (n=7134). When comparing methylphenidate with placebo or no-treatment on ADHD symptoms, we found no differences between the end of parallel trials and the first-period from crossover trials (Χ²=1.06, df=1, p=0.30, I²=5.5%). We also found no differences when combining the end of first-period crossover trials with the end of parallel trials and comparing them to the end of last-period crossover trials (Χ²=3.25, df=1, p=0.07, I²=69.2%). We found no differences in serious and non-serious adverse events, and no risk of period and carryover effects. However, only two trials contributed data to the latter analyses.

CONCLUSIONS

Both parallel and crossover trials seem suitable for investigating methylphenidate in children and adolescents with ADHD, with comparable estimates on ADHD symptom severity and adverse events. However, parallel trials might still offer ethical and statistical advantages over crossover trials.

Juvenile exposure to methylphenidate and guanfacine in rats: effects on early delay discounting and later cocaine-taking behavior

RATIONALE

Both methylphenidate (MPH), a catecholamine reuptake blocker, and guanfacine, an alpha2A agonist, are used to treat attention-deficit hyperactivity disorder (ADHD). Childhood impulsivity, including delay discounting, is associated with increased substance use during adolescence. These effects can be mitigated by juvenile exposure to MPH, but less is known about the long-term effects of developmental exposure to guanfacine in males and females.

OBJECTIVE

This study aims to determine sex differences and dose-dependent effects of juvenile exposure to MPH or guanfacine on delay-discounting and later cocaine self-administration.

METHODS

The dose-dependent effects of vehicle, MPH (0.5, 1, and 2 mg/kg p.o.) or guanfacine (0.003, 0.03, and 0.3 mg/kg, i.p.) on discounting were determined in male and female Sprague-Dawley rats beginning at postnatal day (P)20. At P90, the amount, motivation, and sensitivity to cocaine following early drug exposure were determined with self-administration.

RESULTS

Guanfacine, but not MPH, significantly reduced weight by 22.9 ± 4.6% in females. MPH dose dependently decreased delay discounting in both juvenile males and females, while guanfacine was only effective in males. Discounting was associated with cocaine self-administration in vehicle males (R² = -0.4, P < 0.05) and self-administration was reduced by guanfacine treatment (0.3 mg/kg). Guanfacine significantly decreased cocaine sensitivity in both sexes.

CONCLUSIONS

These data suggest that MPH is effective in reducing delay discounting in both sexes. Due to both weight loss and ineffectiveness on discounting in females, guanfacine should be used only in males to reduce delay discounting and later cocaine use.

Cross-species models of attention-deficit/hyperactivity disorder and autism spectrum disorder: lessons from CNTNAP2, ADGRL3, and PARK2

Animal and cellular models are essential tools for all areas of biological research including neuroscience. Model systems can also be used to investigate the pathophysiology of psychiatric disorders such as attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). In this review, we provide a summary of animal and cellular models for three genes linked to ADHD and ASD in human patients - CNTNAP2, ADGRL3, and PARK2. We also highlight the strengths and weaknesses of each model system. By bringing together behavioral and neurobiological data, we demonstrate how a cross-species approach can provide integrated insights into gene function and the pathogenesis of ADHD and ASD. The knowledge gained from transgenic models will be essential to discover and validate new treatment targets for these disorders.

Integrative genomic analysis of methylphenidate response in attention-deficit/hyperactivity disorder

Methylphenidate (MPH) is the most frequently used pharmacological treatment in children with attention-deficit/hyperactivity disorder (ADHD). However, a considerable interindividual variability exists in clinical outcome. Thus, we performed a genome-wide association study of MPH efficacy in 173 ADHD paediatric patients. Although no variant reached genome-wide significance, the set of genes containing single-nucleotide polymorphisms (SNPs) nominally associated with MPH response (P < 0.05) was significantly enriched for candidates previously studied in ADHD or treatment outcome. We prioritised the nominally significant SNPs by functional annotation and expression quantitative trait loci (eQTL) analysis in human brain, and we identified 33 SNPs tagging cis-eQTL in 32 different loci (referred to as eSNPs and eGenes, respectively). Pathway enrichment analyses revealed an over-representation of genes involved in nervous system development and function among the eGenes. Categories related to neurological diseases, psychological disorders and behaviour were also significantly enriched. We subsequently meta-analysed the association with clinical outcome for the 33 eSNPs across the discovery sample and an independent cohort of 189 ADHD adult patients (target sample) and we detected 15 suggestive signals. Following this comprehensive strategy, our results provide a better understanding of the molecular mechanisms implicated in MPH treatment effects and suggest promising candidates that may encourage future studies.

Bupropion for attention deficit hyperactivity disorder (ADHD) in adults

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is a prevalent neurobiological condition, characterised by behavioral and cognitive symptoms such as inattention, impulsivity and/or excessive activity. The syndrome is commonly accompanied by psychiatric comorbidities and is associated with educational and occupational underachievement.Although psychostimulant medications are the mainstay of treatment for ADHD, not all adults respond optimally to, or can tolerate, these medicines. Thus, alternative non-stimulant treatment approaches for ADHD have been explored. One of these alternatives is bupropion, an aminoketone antidepressant and non-competitive antagonism of nicotinic acetylcholine receptors. Bupropion is registered for the treatment of depression and smoking cessation, but is also used off-label to treat ADHD.

OBJECTIVES

To assess the effects and safety of bupropion for the treatment of adults with ADHD.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and seven other databases in February 2017. We also searched three trials registers and three online theses portals. In addition, we checked references of included studies and contacted study authors to identify potentially relevant studies that were missed by our search.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) that evaluated the effects (including adverse effects) of bupropion compared to placebo in adults with ADHD.

DATA COLLECTION AND ANALYSIS

Two review authors (WV, GB) independently screened records and extracted data using a data extraction sheet that we tested in a pilot study. We extracted all relevant data on study characteristics and results. We assessed risks of bias using the Cochrane 'Risk of bias' tool, and assessed the overall quality of evidence using the GRADE approach. We used a fixed-effect model to pool the results across studies.

MAIN RESULTS

We included six studies with a total of 438 participants. Five studies were conducted in the USA, and one in Iran. All studies evaluated a long-acting version of bupropion, with the dosage ranging from 150 mg up to 450 mg daily. Study intervention length varied from six to 10 weeks. Four studies explicitly excluded participants with psychiatric comorbidity and one study included only participants with opioid dependency. Four studies were funded by industry, but the impact of this on study results is unknown. Two studies were publicly funded and in one of these studies, the lead author was a consultant for several pharmaceutical companies and also received investigator-driven funding from two companies, however none of these companies manufacture bupropion. We judged none of the studies to be free of bias because for most risk of bias domains the study reports failed to provide sufficient details. Using the GRADE approach, we rated the overall quality of evidence as low. We downgraded the quality of the evidence because of serious risk of bias and serious imprecision due to small sample sizes.We found low-quality evidence that bupropion decreased the severity of ADHD symptoms (standardised mean difference -0.50, 95% confidence interval (CI) -0.86 to -0.15, 3 studies, 129 participants), and increased the proportion of participants achieving clinical improvement (risk ratio (RR) 1.50, 95% CI 1.13 to 1.99, 4 studies, 315 participants), and reporting an improvement on the Clinical Global Impression - Improvement scale (RR 1.78, 95% CI 1.27 to 2.50, 5 studies, 337 participants). There was low-quality evidence that the proportion of participants who withdrew due to any adverse effect was similar in the bupropion and placebo groups (RR 1.20, 95% CI 0.35 to 4.10, 3 studies, 253 participants). The results were very similar when using a random-effects model and when we analysed only studies that excluded participants with a psychiatric comorbidity.

AUTHORS' CONCLUSIONS

The findings of this review, which compared bupropion to placebo for adult ADHD, indicate a possible benefit of bupropion. We found low-quality evidence that bupropion decreased the severity of ADHD symptoms and moderately increased the proportion of participants achieving a significant clinical improvement in ADHD symptoms. Furthermore, we found low-quality evidence that the tolerability of bupropion is similar to that of placebo. In the pharmacological treatment of adults with ADHD, extended- or sustained-release bupropion may be an alternative to stimulants. The low-quality evidence indicates uncertainty with respect to the pooled effect estimates. Further research is very likely to change these estimates. More research is needed to reach more definite conclusions as well as clarifying the optimal target population for this medicine. Treatment response remains to be reported in a DSM5-diagnosed population. There is also a lack of knowledge on long-term outcomes.

Methylphenidate effects in the young brain: friend or foe?

Attention deficit hyperactivity disorder (ADHD) is one of the most prevalent neuropsychiatry disorders in children and adolescents, and methylphenidate (MPH) is a first-line stimulant drug available worldwide for its treatment. Despite the proven therapeutic efficacy, concerns have been raised regarding the possible consequences of chronic MPH exposure during childhood and adolescence. Disturbances in the neurodevelopment at these crucial stages are major concerns given the unknown future life consequences. This review is focused on the long-term adverse effects of MPH to the brain biochemistry. Reports conducted with young and/or adolescent animals and studies with humans are reviewed in the context of long-term consequences after early life-exposure. MPH pharmacokinetics is also reviewed as there are differences among laboratory animals and humans that may be relevant to extrapolate the findings. Studies reveal that exposure to MPH in laboratory animals during young and/or adolescent ages can impact the brain, but the outcomes are dependent on MPH dose, treatment period, and animal's age. Importantly, the female sex is largely overlooked in both animal and human studies. Unfortunately, human reports that evaluate adults following adolescent or child exposure to MPH are very scarce. In general, human data indicates that MPH is generally safe, although it can promote several brain changes in early ages. Even so, there is a lack of long course patient evaluation to clearly establish whether MPH-induced changes are friendly or foe to the brain and more human studies are needed to assess the adult brain changes that arise from early MPH treatment.

Daily Symptom Profiles of Children With ADHD Treated With Modified-Release Methylphenidate

OBJECTIVE

The aim was to identify subgroups of patients with ADHD with different daily symptom profiles and to characterize their response to modified-release methylphenidate (MR MPH) treatment, using data from the observational trial OBSEER.

METHOD

OBSEER included patients aged 6 to 17 years receiving MR MPH under routine care. To detect subgroups, a latent class cluster analysis was applied. Sex, age, MR MPH dose, and emotional symptoms were considered predictors of response.

RESULTS

The analysis included 637 patients (81.3% male), with a mean age (standard deviation) of 10.1 (2.5) years. A two-class solution best fit the data, identifying a high-severity group (49.8%) with pronounced symptom reduction, and a low-severity group (50.2%) with minor changes throughout the day. Younger age, male sex, and higher MPH doses were predictive of the high-severity class.

CONCLUSION

Children with ADHD treated with MR MPH are heterogeneous, and subgroups with differential treatment response can be identified.

Methylphenidate, cognition, and epilepsy: A double-blind, placebo-controlled, single-dose study

OBJECTIVE

To evaluate the potential efficacy of immediate-release methylphenidate (MPH) for treating cognitive deficits in epilepsy.

METHODS

This was a double-blind, randomized, single-dose, 3-period crossover study in patients with epilepsy and chronic cognitive complaints comparing the effects of placebo and MPH 10 and 20 mg given 1 week apart. Cognitive outcome was evaluated on the basis of an omnibus z score calculated from performance on the Conners Continuous Performance Test 3 (ability to discriminate between target and nontarget stimuli [d'] and hit reaction time standard deviation), Symbol-Digit Modalities Test, and Medical College of Georgia Paragraph Memory Test. Adverse events and seizure frequency were monitored. An open-label follow-up is reported elsewhere.

RESULTS

Thirty-five adult patients with epilepsy participated, of whom 31 finished. Demographics included the following: mean age = 35.3 years (range 20-62 years), 13 men and 18 women, and baseline seizure frequency of 2.8 per month. Epilepsy types were focal (n = 24), generalized (n = 6), or unclassified (n = 1). Mean epilepsy duration was 12.5 years. A statistically significant performance benefit was present at both 10-mg (p = 0.030) and 20-mg (p = 0.034) MPH doses. No seizures were associated with either MPH dose. Adverse effects leading to withdrawal included cognitive "fogginess" (n = 1 on 20 mg), anxiety/agitation (n = 1 on 10 mg), and tachycardia (n = 1). One participant was lost to follow-up after one 20-mg dose without side effect.

CONCLUSIONS

This single-dose study suggests that MPH may be effective in ameliorating some cognitive deficits in patients with epilepsy. Additional studies are required.

CLINICALTRIALSGOV IDENTIFIER

NCT02178995.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that single doses of MPH improve cognitive performance on some measures of attention and processing speed in patients with epilepsy and cognitive complaints.

A Single-Dose, Single-Period Pharmacokinetic Assessment of an Extended-Release Orally Disintegrating Tablet of Methylphenidate in Children and Adolescents with Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

To determine the pharmacokinetic (PK) profile of a proprietary formulation of methylphenidate (MPH) in children and adolescents with attention-deficit/hyperactivity disorder (ADHD) in a phase 1 study. Methylphenidate extended-release orally disintegrating tablets (MPH XR-ODTs) combine two technologies in a single-tablet formulation-an extended-release profile that was designed for once-daily dosing in an ODT that does not require water or chewing for ingestion.

METHODS

This was a single-dose, open-label, single-period, single-treatment study, in which 32 children with ADHD who were receiving MPH in doses of 40 or 60 mg before beginning the study each received a 60-mg dose (2 × 30 mg) of MPH XR-ODT. The following plasma PK parameters of MPH were determined for participants grouped by age (6-7, 8-9, 10-12, and 13-17 years old): maximum concentration (Cmax), time to maximum concentration (Tmax), elimination half-life (T½), area under the curve from 0 hours to infinity (AUCinf), oral clearance (CL/F), and volume of distribution in the terminal phase (Vz/F). Safety and tolerability were also assessed.

RESULTS

A total of 32 participants received the study drug. For all participants, plasma concentration-time profiles of MPH exhibited a broad peak after administration of MPH XR-ODT through ∼8 hours, indicating extended release from the formulation, followed by an apparent first-order elimination phase. As age increased, MPH exposure decreased and mean estimates of CL/F increased; however, weight-normalized CL/F values were comparable across age groups. Similarly, mean estimates of Vz/F increased with age, but weight-normalization decreased differences across age groups, with the exception of the youngest age group, which had higher values. All adverse events (AEs) were mild.

CONCLUSION

This XR-ODT formulation of MPH demonstrated weight-normalized clearance rates that were consistent across all age groups, a PK profile consistent with once-daily dosing, and an AE profile consistent with this class of medication in children and adolescents with ADHD.

Mindfulness Meditation Improves Mood, Quality of Life, and Attention in Adults with Attention Deficit Hyperactivity Disorder

OBJECTIVE

Adults with attention deficit hyperactivity disorder (ADHD) display affective problems and impaired attention. Mood in ADHD can be improved by mindful awareness practices (MAP), but results are mixed regarding the enhancement of attentional performance. Here we evaluated MAP-induced changes in quality of life (QoL), mood, and attention in adult ADHD patients and controls using more measures of attention than prior studies.

METHODS

Twenty-one ADHD patients and 8 healthy controls underwent 8 weekly MAP sessions; 22 similar patients and 9 controls did not undergo the intervention. Mood and QoL were assessed using validated questionnaires, and attention was evaluated using the Attentional Network Test (ANT) and the Conners Continuous Performance Test (CPT II), before and after intervention.

RESULTS

MAP enhanced sustained attention (ANT) and detectability (CPT II) and improved mood and QoL of patients and controls.

CONCLUSION

MAP is a complementary intervention that improves affect and attention of adults with ADHD and controls.

A review of OROS methylphenidate (Concerta(®)) in the treatment of attention-deficit/hyperactivity disorder

Attention-deficit/hyperactivity disorder (ADHD) is a common neurobehavioural disorder with onset during childhood. It affects a child's development, both at home and at school, and impacts on social, emotional and cognitive functioning, in both the home and the school environment. Untreated ADHD is very often associated with poor academic achievement, low occupational status, increased risk of substance abuse and delinquency. Current practice guidelines recommend a multimodal approach in the treatment of ADHD, which includes educational, behavioural and mental health interventions, and pharmacological management. Stimulant medications, including methylphenidate (MPH) and amphetamine products, are recommended as first-line pharmacotherapy in the treatment of ADHD. The choice of stimulant is influenced by several factors; the most influential factor is the duration of action. Long-acting medication provides benefits long after school and work. It also increases the likelihood of once-daily dosing, thereby eliminating the need for mid-day dosing, making the treatment more private, avoiding stigma and improving adherence to medication. MPH is the most widely used psychotropic medication in child psychiatry. It was first developed for use in children as an oral, immediate-release formulation and more recently as various extended-release formulations. These latter formulations include the 12 h preparation Concerta(®) (osmotic-release oral system [OROS] MPH), which utilizes an osmotic pump system, designed to overcome the difficulties of multiple daily dosing. Since it received approval from the US Food and Drug Administration in August 2000, OROS MPH has been quickly and widely accepted as one of the preferred treatments for ADHD because of its once-daily dosing. This paper reviews the data in support of long-acting OROS MPH in children, adolescents and adults, both in ADHD and in association with its comorbidities.

An observational study of response heterogeneity in children with attention deficit hyperactivity disorder following treatment switch to modified-release methylphenidate

BACKGROUND

Methylphenidate (MPH) has been shown to be effective in the treatment of attention deficit hyperactivity disorder (ADHD) in children. The overall population of children and adolescents with ADHD may comprise distinct clusters of patients that differ in response to MPH. The aim of this analysis was to look for subgroups with different treatment trajectories and to identify their distinctive features.

METHODS

OBSEER was a prospective, observational study examining the effectiveness and safety of once-daily modified-release MPH over 3 months in patients (aged 6-17 years) with ADHD under routine care. Assessments were carried out at baseline (Visit 1), after 1-3 weeks (Visit 2) and 6-12 weeks (Visit 3) after first use of once-daily modified-release MPH. Change in ADHD symptoms, as rated by parents and teachers, was examined post hoc in patients of the intent-to-treat-population (N = 822), using growth-mixture modelling to detect response trajectory groups after switching medication. Age, MPH dose at Visit 1 before medication switch, prescribed once-daily modified-release MPH dose at Visits 1 and 2, conduct problems and emotional symptoms were considered predictors of response subgroups.

RESULTS

Assessing formal statistical criteria and usefulness of the models, a 4-class solution best fitted the data: after switching medication two response groups with severe symptoms at study start and subsequent substantial treatment effects, and two showing no or comparatively little treatment effect, one of which had severe and the other less severe symptoms at study start. Patient age, conduct problems and MPH dose at Visit 1 were predictors of inclusion in subgroups.

CONCLUSIONS

Older children and children with few conduct problems were more likely to be members of a patient cluster with fewer symptoms at study start. Children with a low MPH dose before medication switch had a higher chance of being in the patient cluster with a strong treatment response after switching medication. The current analyses should assist in identifying children likely to achieve a favourable treatment course with MPH and, additionally, those who are in need of alternative treatment options.

Factors influencing parental decision making about stimulant treatment for attention-deficit/hyperactivity disorder

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) is a pediatric psychological condition commonly treated with stimulant medications. Negative media reports and stigmatizing societal attitudes surrounding the use of these medications make it difficult for parents of affected children to accept stimulant treatment, despite it being first line therapy.

OBJECTIVE

The purpose of this study was to identify factors that influence parental decision making regarding stimulant treatment for ADHD.

METHODS

A systematic review of the literature was conducted to identify studies: 1) that employed qualitative methodology, 2) that highlighted treatment decision(s) about stimulant medication, 3) in which the decision(s) were made by the parent of a child with an official ADHD diagnosis, and 4) that examined the factors affecting the decision(s) made. Individual factors influencing parental treatment decision making, and the major themes encompassing these factors, were identified and followed by a thematic analysis.

RESULTS

Eleven studies reporting on the experiences of 335 parents of children with ADHD were included. Four major themes encompassing influences on parents' decisions were derived from the thematic analysis performed: confronting the diagnosis, external influences, apprehension regarding therapy, and experience with the healthcare system.

CONCLUSIONS

The findings of this systematic review reveal that there are multiple factors that influence parents' decisions about stimulant therapy. This information can assist clinicians in enhancing information delivery to parents of children with ADHD, and help reduce parental ambivalence surrounding stimulant medication use. Future work needs to address parental concerns about stimulants, and increase their involvement in shared decision making with clinicians to empower them to make the most appropriate treatment decision for their child.

Methylphenidate in mania project (MEMAP): study protocol of an international randomised double-blind placebo-controlled study on the initial treatment of acute mania with methylphenidate

BACKGROUND

Treatment of patients with acute mania remains a considerable medical challenge since onset of action of antimanic medication is delayed for several days. Psychostimulants could have an earlier onset of action. This assumption is based on the 'vigilance regulation model of mania' which postulates that vigilance is unstable in manic patients. Accordingly, vigilance-stabilising psychostimulants could be more useful than conventional treatment in acute mania. We present here the study protocol of a trial intended to study the efficacy and safety of methylphenidate in the initial treatment of acute mania.

METHODS/DESIGN

A multi-centre, randomised, double-blind, placebo-controlled clinical trial will be conducted in 88 bipolar inpatients with acute mania. Male and female patients older than 18 years will be randomised to treatment with either methylphenidate (20 to 40 mg/day) or placebo for 2.5 days, given once or twice daily. The main outcome measure is the reduction in the Young Mania Rating Scale (YMRS) after 2.5 days of treatment. Other outcome measures include the Positive and Negative Syndrome Scale-Excited Component (PANSS-EC) the Clinical Global Impression-Bipolar Scale (CGI-BP), the Screen for Cognitive Impairment in Psychiatry (SCIP), actigraphy and the EEG-'Vigilance Algorithm Leipzig' (VIGALL).

DISCUSSION

A positive study outcome of the proposed study could substantially impact our understanding of the etiopathogenesis of mania and open new treatment perspectives.

Response to methylphenidate by adult and pediatric patients with attention-deficit/hyperactivity disorder: the Spanish multicenter DIHANA study

BACKGROUND

The purpose of this multicenter Spanish study was to evaluate the response to immediate-release methylphenidate by children and adults diagnosed with attention-deficit/hyperactivity disorder (ADHD), as well as to obtain information on current therapy patterns and safety characteristics.

METHODS

This multicenter, observational, retrospective, noninterventional study included 730 patients aged 4-65 years with a diagnosis of ADHD. Information was obtained based on a review of medical records for the years 2002-2006 in sequential order.

RESULTS

The ADHD predominantly inattentive subtype affected 29.7% of patients, ADHD predominantly hyperactive-impulsive was found in 5.2%, and the combined subtype in 65.1%. Overall, a significant lower Clinical Global Impression (CGI) score and mean number of DSM-IV TR (Diagnostic and Statistical Manual of Mental Disorders Fourth Edition, Text Revision) symptoms by subtype were found after one year of treatment with immediate-release methylphenidate; CGI decreased from 4.51 to 1.69, symptoms of inattention from 7.90 to 4.34, symptoms of hyperactivity from 6.73 to 3.39, and combined subtype symptoms from 14.62 to 7.7. Satisfaction with immediate-release methylphenidate after one year was evaluated as "very satisfied" or "satisfied" by 86.90% of the sample; 25.75% of all patients reported at least one adverse effect. At the end of the study, 41.47% of all the patients treated with immediate-release methylphenidate were still receiving it, with a mean time of 3.80 years on therapy.

CONCLUSION

Good efficacy and safety results were found for immediate-release methylphenidate in patients with ADHD.

Translational application of neuromodulation of decision-making

Recent cognitive neuroscience studies indicate that noninvasive brain stimulation can modulate a wide spectrum of behaviors in healthy individuals. Such modulation of behaviors provides novel insights into the fundamentals and neurobiology of cognitive functions in the healthy brain, but also suggests promising prospects for translational applications into clinical populations. One type of behavior that can be modulated with noninvasive brain stimulation is decision-making. For instance, brain stimulation can induce more cautious or riskier behaviors. The capacity of influencing processes involved in decision-making is of particular interest because such processes are at the core of human social and emotional functioning (or dysfunctioning). We review cognitive neuroscience studies that have successfully modulated processes involved in decision-making with transcranial direct current stimulation (tDCS) or transcranial magnetic stimulation (TMS), including risk taking, reward seeking, impulsivity, and fairness consideration. We also discuss potential clinical relevance of these findings for patients who have still unmet therapeutic need and whose alterations in decision-making represent hallmarks of their clinical symptomatology, such as individuals with addictive disorders.

Amfetamine and methylphenidate medications for attention-deficit/hyperactivity disorder: complementary treatment options

Attention-deficit/hyperactivity disorder (ADHD) is one of the most common neurodevelopmental disorders among school-aged children. It is highly symptomatic and associated with significant impairment. This review examines the role of stimulant medications in the treatment of children and adolescents with ADHD. Published clinical studies that compared methylphenidate- and amfetamine-based stimulants in children and adolescents with ADHD support the therapeutic utility of stimulant treatments, and suggest robust efficacy and acceptable safety outcomes in groups treated with either stimulant. Evidence-based guidelines agree that each patient with ADHD is unique and individual treatment strategies that incorporate both drug and non-drug treatment options should be sought. In seeking to optimize individual response and outcomes to stimulant therapy, important considerations include the selection of stimulant class, the choice of long- or short-acting stimulant formulations, addressing effectively any emergent adverse effects and strategies aimed at enhancing adherence to dosing regimen and persistence on therapy.

Solution- and solid-state conformations of C(α)-alkyl analogues of methylphenidate (Ritalin) salts: avoidance of gauche(+)gauche(-) interactions

Alkyl analogues of methylphenidate (Ritalin) salts are slow onset, long duration dopamine reuptake inhibitors with a potential use as a cocaine abuse pharmacotherapy. X-ray crystallographic studies and nuclear magnetic resonance (NMR) investigations strongly suggest that avoidance of sterically unfavorable gauche(-)gauche(+) orientations effectively influences both the C(α)-alkyl side chain conformation and the formation of a predominant rotamer about the CH-CH bond ligating piperidine and C(Ar)R moieties. The favored CH-CH rotamer in D(2)O and in CD(2)Cl(2) of the pharmacologically interesting i-Bu and CH(2)-cyc-Pnt (RS,RS)-salts has the same antiperiplanar arrangement that was found in the crystal structures, although there clearly is a fast equilibrium involving smaller amounts of synclinal partners. While the rotamer in the (RS,SR)-i-Bu HCl crystal structure exhibits a synclinal orientation for the vicinal pair of adjacent methine protons, the weighted time-averaged arrangement for these protons becomes almost completely antiperiplanar when the crystals are dissolved in D(2)O. Increased steric congestion around the CH-CH bond in the analogous N-methyl tertiary ammonium salts seems to augment the quantity of the preferred rotamer within the mixture. The stereochemistry of the species observed via NMR seems to arise from specific combinations of N-methyl orientation and avoidance of sterically unfavorable gauche(-)gauche(+) arrangements.

Pharmacogenetic predictors of methylphenidate dose-response in attention-deficit/hyperactivity disorder

OBJECTIVE

Because of significant individual variability in attention-deficit/hyperactivity disorder (ADHD) medication response, there is increasing interest in identifying genetic predictors of treatment effects. This study examined the role of four catecholamine-related candidate genes in moderating methylphenidate (MPH) dose-response.

METHOD

Eighty-nine stimulant-naive children with ADHD 7 to 11 years old participated in a randomized, double-blind, crossover trial of long-acting MPH. Parents and teachers assessed each child's response on placebo and three MPH dosage levels using the Vanderbilt ADHD rating scales. Children were genotyped for polymorphisms in the 3' untranslated region of dopamine transporter (DAT), exon 3 on dopamine receptor D(4) (DRD4), codon 158 on catechol-O-methyltransferase, and the adrenergic α(2A)-receptor promoter. Linear mixed models evaluated gene, dose (milligrams per kilogram per day), and gene-by-dose effects on inattentive and hyperactive-impulsive domain outcomes.

RESULTS

The most statistically significant gene-by-dose interactions were observed on hyperactive-impulsive symptoms for DRD4 and DAT polymorphisms, with participants lacking the DAT 10-repeat allele showing greater improvements in symptoms with increasing dose compared with 10-repeat carriers (p = .008) and those lacking the DRD4 4-repeat allele showing less improvement across MPH doses compared with 4-repeat carriers (p = 0.02).

CONCLUSIONS

This study suggests that DAT and DRD4 polymorphisms may be associated with individual variability in MPH dose-response, although further research in larger samples is required to confirm these findings and their clinical utility.

CLINICAL TRIAL REGISTRATION INFORMATION

Response Variability in Children with Attention-Deficit/Hyperactivity Disorder (ADHD); http://www.clinicaltrials.gov; NCT01238822.

Long-term outcomes with medications for attention-deficit hyperactivity disorder: current status of knowledge

Attention-deficit hyperactivity disorder (ADHD), a common neurobehavioural disorder characterized by inattention, hyperactivity and impulsivity, is a chronic disorder and often persists into adulthood. CNS stimulants have been the most well known treatment for ADHD for several decades due to their high effectiveness, good safety profiles and relatively minor adverse effects. Non-stimulant agents, including atomoxetine, extended-release guanfacine and extended-release clonidine (US FDA approved), and several non-FDA-approved agents, such as bupropion and tricyclic antidepressants (TCAs), were recently proven to be effective alternatives to the stimulants in several open-label and placebo-controlled trials. However, most medication trials for ADHD have been short term and thus have not provided information on the long-term outcomes of ADHD treatment. Since the medical treatment of many children with ADHD, especially those with more severe symptoms or co-morbid disorders, has to be continued for several years, recent studies have shifted their focus from the acute effectiveness of stimulants or non-stimulant drugs to the long-term outcomes of medications for ADHD. Evidence has shown that stimulants, along with the non-stimulants atomoxetine and extended-release guanfacine, are continuously effective for 24-month treatment periods with few and tolerable adverse effects.

Safety of stimulant treatment in attention deficit hyperactivity disorder: part II

IMPORTANCE OF THE FIELD

Attention deficit hyperactivity disorder (ADHD) is the most common childhood psychiatric disorder and in at least 50% of cases persists into adulthood. Treatment of ADHD with stimulants is one of the oldest and most effective pharmacological treatments in psychiatry. Yet, there continues to be controversy over the safety of stimulant medications in the treatment of ADHD.

AREAS COVERED IN THIS REVIEW

This paper is a continuation of an earlier paper that reviewed the safety profile of newer stimulant agents, especially in relation to special populations. This part II reviews, through essentially an organ-system approach, the various clinical concerns that have been raised over the safety of stimulant medications. This includes neuropsychiatric, cardiovascular effects on growth and development, and a number of other less common concerns.

WHAT THE READER WILL GAIN

A thorough review of safety concerns in stimulants that emphasizes clinical information, case reports, open series or controlled trials relating to stimulant use in the treatment of ADHD.

TAKE HOME MESSAGE

While many safety concerns have been raised in the use of stimulants, the vast majority of treatment complications are either quickly reversible or easily manageable with appropriate clinical care. The negative consequences of untreated ADHD clearly outweigh the risks of the stimulant medicines when used in an appropriate and careful manner.

Pharmacokinetic variability of long-acting stimulants in the treatment of children and adults with attention-deficit hyperactivity disorder

Methylphenidate- and amfetamine-based stimulants are first-line pharmacotherapies for attention-deficit hyperactivity disorder, a common neurobehavioural disorder in children and adults. A number of long-acting stimulant formulations have been developed with the aim of providing once-daily dosing, employing various means to extend duration of action, including a transdermal delivery system, an osmotic-release oral system, capsules with a mixture of immediate- and delayed-release beads, and prodrug technology. Coefficients of variance of pharmacokinetic measures can estimate the levels of pharmacokinetic variability based on the measurable variance between different individuals receiving the same dose of stimulant (interindividual variability) and within the same individual over multiple administrations (intraindividual variability). Differences in formulation clearly impact pharmacokinetic profiles. Many medications exhibit wide interindividual variability in clinical response. Stimulants with low levels of inter- and intraindividual variability may be better suited to provide consistent levels of medication to patients. The pharmacokinetic profile of stimulants using pH-dependent bead technology can vary depending on food consumption or concomitant administration of medications that alter gastric pH. While delivery of methylphenidate with the transdermal delivery system would be unaffected by gastrointestinal factors, intersubject variability is nonetheless substantial. Unlike the beaded formulations and, to some extent (when considering total exposure) the osmotic-release formulation, systemic exposure to amfetamine with the prodrug stimulant lisdexamfetamine dimesylate appears largely unaffected by such factors, likely owing to its dependence on systemic enzymatic cleavage of the precursor molecule, which occurs primarily in the blood involving red blood cells. The high capacity but as yet unidentified enzymatic system for conversion of lisdexamfetamine dimesylate may contribute to its consistent pharmacokinetic profile. The reasons underlying observed differential responses to stimulants are likely to be multifactorial, including pharmacodynamic factors. While the use of stimulants with low inter- and intrapatient pharmacokinetic variability does not obviate the need to titrate stimulant doses, stimulants with low intraindividual variation in pharmacokinetic parameters may reduce the likelihood of patients falling into subtherapeutic drug concentrations or reaching drug concentrations at which the risk of adverse events increases. As such, clinicians are urged both to adjust stimulant doses based on therapeutic response and the risk for adverse events and to monitor patients for potential causes of pharmacokinetic variability.

A double-blind, randomized, placebo/active controlled crossover evaluation of the efficacy and safety of Ritalin ® LA in children with attention-deficit/hyperactivity disorder in a laboratory classroom setting

OBJECTIVES

The primary objective of this study was to demonstrate efficacy of Ritalin(®) LA 20 mg by showing superiority to placebo and noninferiority to Medikinet(®) Retard in a laboratory classroom setting. Secondary objectives included safety/tolerability and further efficacy parameters.

METHODS

A total of 147 children with attention-deficit/hyperactivity disorder (ADHD) diagnosed by the Kiddie Schedule for Affective Disorders and Schizophrenia (K-SADS) and aged 6-14 (81% males) and known to be methylphenidate (MPH) responders were enrolled in this multicenter, double-blind, randomized, placebo/active-controlled, three-period (7 days each) crossover study. The Swanson, Kotlin, Agler, M-Flynn, and Pelham (SKAMP) scale was used for efficacy ratings. The mean of SKAMP Combined ratings performed at 10:30 a.m., at 12:00 a.m., and at 1:30 p.m. was defined as the primary parameter.

RESULTS

In all, 146 patients completed all treatment periods. Intensity and frequency of adverse events were comparable between the two formulations. Ritalin(®) LA demonstrated superiority compared to placebo (p<0.0001). The observed difference in the SKAMP scores between Ritalin(®) LA and Medikinet(®) Retard between the hours 1.5 until 4.5 did not exceed the noninferiority margin (p=0.0003); therefore, the difference is regarded as not clinically relevant. Similar results were obtained for the secondary efficacy variables.

CONCLUSION

Ritalin(®) LA is an efficacious, well-tolerated treatment option for children aged 6-14 with ADHD.

Attention deficit hyperactivity disorder in adults

OBJECTIVE

To examine available literature regarding attention deficit hyperactivity disorder (ADHD) in adults.

METHODS

An electronic literature search of peer-reviewed English language articles using MEDLINE (without time limits) was undertaken.

RESULTS

Symptoms of ADHD in adults exert a substantial negative impact on daily life, including work, social life and relationships. Co-morbidities are common, further impairing quality of life. Diagnosis of adult ADHD can be difficult, as current criteria require evidence of symptom onset before the age of 7 years and impact on activities typically undertaken by children. Drug therapy is the first-line treatment for adult ADHD, particularly stimulant medication. However, methylphenidate (MPH) immediate-release tablets require three or more times daily dosing, which can impact on compliance, while demonstrating a loss of symptomatic benefit later in the day. Extended-release preparations of MPH, mixed amphetamine salts and dexamphetamine can provide symptom control for 6-12 h and the non-stimulant atomoxetine has demonstrated benefit in reducing ADHD symptoms. These therapies are generally well tolerated, but may be associated with adverse effects on the cardiovascular system, which need to be further assessed in controlled clinical trials. Psychological therapy may be beneficial in adults who continue to experience clinically significant symptoms while receiving pharmacotherapy.

CONCLUSION

Further research in all areas of adult ADHD is urgently needed.

Intermittent methylphenidate during adolescent development produces locomotor hyperactivity and an enhanced response to cocaine compared to continuous treatment in rats

The consequences of chronic methylphenidate (MPH) administration in adolescents for the treatment of attention-deficit/hyperactivity disorder (ADHD) remain to be fully understood. Studies in rats indicate that the pharmacokinetics of psychostimulant administration can powerfully influence the behavioral and neural consequences of chronic treatment. The purpose of the present study was to assess the effects of intermittent (0.8 or 1.6mg/kg, s.c., twice daily) versus continuous (1.6 or 3.2mg/kg/day via osmotic minipump) MP administration across four weeks of adolescent development in rats. Results indicate that intermittent treatment produced hyperactivity in a novel open field and increased sensitivity to both the reinforcing and locomotor-activating effects of cocaine. In contrast, continuous MPH resulted in a hypoactive response to the novel open field and a reduced sensitivity to both operant and non-contingent cocaine. To the extent that the continuous release condition models the sustained-release formulations utilized in human ADHD treatment, we interpret these data to indicate that sustained-release formulations are less likely to advance a risk of subsequent substance abuse.

Treating attention-deficit/hyperactivity disorder beyond symptom control alone in children and adolescents: a review of the potential benefits of long-acting stimulants

Attention-deficit/hyperactivity disorder (ADHD), one of the most common neuropsychiatric conditions of childhood, often has a chronic course and persists into adulthood in many individuals. ADHD may have a clinically important impact on health-related quality of life in children, a significant impact on parents' emotional health and interfere with family activities/cohesion. To date, the main targets of ADHD treatment have focused on reducing the severity of symptoms during the school day and improving academic performance. However, the treatment of ADHD should reach beyond symptom control to address the issues of social competencies and improvement of health-related quality of life from the perspectives of individuals with ADHD and their families, to support them in reaching their full developmental potential. Methylphenidate (MPH) is recognised as the first-line choice of pharmacotherapy for ADHD in children and adolescents. This paper focuses on the importance and benefits to child development of ADHD symptom control beyond the school day only, i.e. extending into late afternoon and evening and uses the example of an extended-release MPH formulation (OROS((R)) MPH) to demonstrate the potential benefits of active full day coverage (12 h) with a single daily dose. Concerns of long-term stimulant treatment are also discussed.

Safety of stimulant treatment in attention deficit hyperactivity disorder: Part I

BACKGROUND

The safety profile of newer stimulant products is of interest. Because most studies focus on school-age children, there is also an increased interest in the treatment of other populations. Concern continues for the risk of substance abuse in the use of stimulants.

OBJECTIVE

The purpose of this paper is to review published data on the safety and tolerability of the newer forms of stimulants, treatment in special populations, and the risks of substance abuse and dependence in the treatment of attention deficit hyperactivity disorder.

METHODS

Literature obtained through Medline and Pubmed from 1995 were reviewed as well as key articles referenced in the literature.

CONCLUSIONS

The use of the newer stimulant agents shows a safety profile of frequent, but usually mild side effects. They are generally safe in special populations. The risk of developing long-term substance abuse with attention deficit hyperactivity disorder, without co-morbidities, is small and may decrease with proper treatment. More research is needed.

Measuring methylphenidate response in attention-deficit/hyperactvity disorder: how are laboratory classroom-based measures related to parent ratings?

BACKGROUND

Methylphenidate (MPH) is an efficacious and normally well-tolerated treatment for attention-deficit/hyperactivity disorder (ADHD). Although treatment effects are usually assessed using parent-rating scales, these can be supplemented by more objective methods. Here we examine the associations between ratings and one such method, assessments made across the day in the laboratory classroom.

METHOD

Comparison of Methylphenidates in the Analog Classroom Setting (COMACS) was made in a large (n = 184) placebo-controlled trial comparing Equasym XL/Metadate CD, Concerta, and placebo (PLA) using a Laboratory School protocol. Therapeutic effects were measured using direct observation, scores on a simple math productivity task and parent ratings.

RESULTS

Treatment effects were observed on all measures. Laboratory measures were correlated with each other, most strongly between Swanson, Kotkin, Agler, M-Flynn and Pelham Scale (SKAMP) inattention and Permanent Product Measure of Performance (PERMP). Parental ratings were correlated with classroom measures during the main morning period (1.5-4.5 hours after dosing) and to a lesser extent in the afternoon (6.0-7.5 hours after dosing), but not, by and large, immediately after dosing or in the evening. The morning correlations seemed stronger for female than for male participants.

DISCUSSION

The results suggest that parental ratings and direct observations tap different aspects of MPH response and that both may be required for comprehensive assessment.

Attention-deficit-hyperactivity disorder: an update

Attention-deficit-hyperactivity disorder (ADHD) is a common neuropsychiatric disorder that impairs social, academic, and occupational functioning in children, adolescents, and adults. In patients with ADHD, neurobiologic research has shown a lack of connectivity in key brain regions, inhibitory control deficits, delayed brain maturation, and noradrenergic and dopaminergic dysfunction in multiple brain regions. The prevalence of this disorder in the United States is 6-9% in youth (i.e., children and adolescents) and 3-5% in adults. Prevalence rates for youth are similar worldwide. Children with ADHD are at greater risk than children without ADHD for substance abuse and delinquency whether or not they receive drug therapy; however, early treatment with psychoeducation as well as drug therapy and/or behavioral intervention may decrease negative outcomes of ADHD, including the rate of conduct disorder and adult antisocial personality disorder. Drug therapy is effective for all age groups, even preschoolers, and for late-onset ADHD in adults. Stimulants, such as methylphenidate and amphetamine, are the most effective therapy and have a good safety profile; although recent concerns of sudden unexplained death, psychiatric adverse effects, and growth effects have prompted the introduction of other therapies. Atomoxetine, a nonstimulant, has no abuse potential, causes less insomnia than stimulants, and poses minimal risk of growth effects. Other drug options include clonidine and guanfacine, but both can cause bradycardia and sedation. Polyunsaturated fatty acids (fish oil), acetyl-L-carnitine, and iron supplements (for youth with low ferritin levels) show promise in improving ADHD symptoms. As long-term studies show that at least 50% of youth are nonadherent with their drug therapy as prescribed over a 1-year period, long-acting formulations (administered once/day) may improve adherence. Comorbid conditions are common in patients with ADHD, but this patient population can be treated effectively with individualized treatment regimens of stimulants, atomoxetine, or bupropion, along with close monitoring.

Pharmacokinetics of methylphenidate transdermal system (MTS): results from a laboratory classroom study

OBJECTIVE

To evaluate the pharmacokinetic properties of the methylphenidate transdermal system (MTS) in pediatric patients diagnosed with ADHD (attention-deficit/hyperactivity disorder) in a laboratory school setting.

METHOD

A phase II, randomized, double-blind, placebo-controlled, laboratory classroom study was conducted with prior dose optimization. Children (aged 6-12 years) with ADHD were titrated over 5 weeks to an optimal clinical MTS dose (10, 15, 20, or 30 mg/9 h). Participants were randomized to 1 week of either MTS or corresponding placebo, followed by crossover to the alternate treatment. Laboratory school evaluations, including pharmacokinetic blood sampling, occurred at the end of each treatment.

RESULTS

MTS delivered d- and l-MPH (methylphenidate) into the systemic circulation throughout the 9-hour wear time, and plasma concentrations declined rapidly after patch removal. Over the time-course of clinical effectiveness (2-12 h), mean plasma concentrations of d-MPH at the most frequently titrated doses (15 and 20 mg/9 h) ranged from 4.97 to 28.3 ng/mL. Systemic exposure increased approximately dose proportionately. Plasma concentrations of the l-MPH were approximately one-half to two-thirds those for d-MPH.

CONCLUSIONS

Plasma concentrations of the much less active l-MPH were consistently lower than those of d-MPH. The clinical relevance of the MTS pharmacokinetic profile is discussed.

Rebound effects with long-acting amphetamine or methylphenidate stimulant medication preparations among adolescent male drivers with attention-deficit/hyperactivity disorder

This study investigated whether OROS methylphenidate (OROS MPH, Concerta) or extended-release mixed amphetamine salts (se-AMPH ER, Adderall XR) were associated with worsening of driving performance, or drug rebound, relative to placebo 16-17 hours post-ingestion. Nineteen male adolescent drivers aged 17-19 with attention-deficit/hyperactivity disorder (ADHD) were compared on a virtual reality driving simulator and an on-road drive after taking 72 mg of OROS MPH, 30 mg of se-AMPH ER, or placebo. Medication was taken at 08:00 in a randomized, double-blind, placebo-controlled, crossover study. Participants drove a simulator at 17:00, 20:00, 23:00, and 01:00, and drove their own cars over a 16-mile road course at 24:00. The main outcome measures were composite scores of driving performance. Neither OROS MPH nor se-AMPH ER was associated with significant worsening of simulator performance relative to placebo 17 hours post-ingestion in group comparisons. However, inattentive on-road driving errors were significantly more common on se-AMPH ER relative to placebo at midnight (p = 0.04), suggesting possible rebound. During both late simulator and on-road testing, driving performance variance was approximately 300% greater during the se-AMPH ER compared to the OROS MPH condition.

Slow-onset, long-duration, alkyl analogues of methylphenidate with enhanced selectivity for the dopamine transporter

Methylphenidate analogues, in which the carbomethoxy has been replaced by an alkyl group and with different phenyl substituents, have been synthesized and tested in monoamine transporter assays. As predicted from a pharmacophore model, most of the RR/SS diastereomers showed high potency as dopamine reuptake inhibitors. Analogues with a 4-chlorophenyl group and an unbranched initial alkyl atom had consistently enhanced selectivity for the dopamine transporter. The most potent compounds were those with a three- or four-carbon chain. The "inactive" RS/SR diastereomers showed substantial activity when the phenyl substituent was 3,4-dichloro. On a locomotor assay, one compound was found to have a slow onset and a long duration of action. The activity of these compounds provides additional evidence for a conformational/superposition model of methylphenidate with cocaine-like structures. A ketone analogue, obtained by hydrogenating a previously described vinylogous amide, had activity similar to that of methylphenidate.

Questões atuais no tratamento farmacológico do TDAH em adultos com metilfenidato

O tratamento farmacológico do transtorno do déficit de atenção com hiperatividade (TDAH) em adultos inclui o uso de psicoestimulantes, antidepressivos e atomoxetina, sendo o primeiro considerado a indicação de primeira escolha. A eficácia do metilfenidato foi demonstrada em adultos quando se empregavam doses maiores, proporcionalmente similares àquelas usadas em estudos em crianças. O perfil de eventos adversos do metilfenidato, incluindo aqueles relativos ao sistema cardiovascular, parece bastante seguro.

ADHD: new pharmacological treatments on the horizon

Attention-deficit/hyperactivity disorder (ADHD) is the most common neurobehavioral disorder affecting school-age children. In many cases, symptoms persist into adolescence and adulthood, causing significant lifelong impairments in academic, career, and social functioning. The stimulants methylphenidate and amphetamines have been used for decades as first-line therapy for the treatment of ADHD. Short-acting stimulant formulations control symptoms only for a few hours, creating the need for multiple daily doses of the medication. For school-age children, this necessitates administering medication during school hours, creating the potential for embarrassment and noncompliance. To offset these problems, longer acting stimulant formulations have been developed. Long-acting medications often control symptoms for up to 8 hours with only one daily dose of the medication, eliminating the need for in-school administration. Some long-acting stimulants are designed to control symptoms for up to 10 to 12 hours. Although stimulants are effective in most cases, some children are unable to tolerate these medications. Nonstimulant options are available for the treatment of ADHD and include atomoxetine, alpha-adrenergic agents, and antidepressants. Of these, atomoxetine is the only medication approved to treat ADHD. In spite of the number of medications available for the management of ADHD, treatment options with greater flexibility and reduced side effects are still desirable. A transdermal methylphenidate patch has recently been approved, and advances to existing stimulants currently under development include an amphetamine prodrug and a longer acting formulation of amphetamine. In addition, a number of nonstimulant entities, including guanfacine and modafinil, are under development for the treatment of ADHD.

Clinical spectrum of the osmotic-controlled release oral delivery system (OROS), an advanced oral delivery form

BACKGROUND

The osmotic-controlled release oral delivery system, OROS, is an advanced drug delivery technology that uses osmotic pressure as the driving force to deliver pharmacotherapy, usually once-daily, in several therapeutic areas.

OBJECTIVE

The purpose of this review is to discuss the evolution of OROS technology and examine the many therapeutic areas where OROS products are being used.

METHODS

A search of Medline and EMBASE were performed using the keywords 'OROS' and 'osmotic delivery' for the period January 1990 to June 2005. Data were also obtained from the manufacturers' websites and associated publications.

RESULTS

OROS technology has evolved over the last 30 years, resulting in four systems: the elementary osmotic pump; the two-layer osmotic push-pull tablet; the advanced longitudinally compressed tablet multilayer formulation; and, the L-OROS system. OROS technology is employed for drug delivery in many therapeutic areas including: cardiovascular medicine, endocrinology, urology, and central nervous system (CNS) therapeutics. Two calcium channel blockers utilizing OROS technology for the treatment of hypertension are nifedipine and verapamil. Glipizide extended-release is used for the treatment of type 2 diabetes. Doxazosin is used for the treatment of benign prostatic hyperplasia, and oxybutynin for overactive bladder. Most recent developments are with drugs that affect the CNS, including the use of methylphenidate for treatment of attention deficit hyperactivity disorder, paliperidone extended-release and OROS hydromorphone, which are under clinical development for schizophrenia and chronic pain, respectively.

CONCLUSIONS

Drug delivery using the various OROS products can result in an improved safety profile, stable drug concentrations, uniform drug effects, and reduced dosing frequency. OROS technology has also enabled the use of an effective starting dose, without the need for dose titration, which allows the achievement of symptom control much earlier than that observed with immediate-release preparations. Such attributes can enhance patient compliance and convenience, thereby ensuring efficacy and improving patient outcomes.

New methylphenidate formulations for the treatment of attention-deficit/hyperactivity disorder

dl-Methylphenidate (MPH) remains the most widely used pharmacological agent in the treatment of attention-deficit/hyperactivity disorder (ADHD). The predominantly dopaminergic mechanism of the psychostimulant actions has become more clearly defined. Neuroimaging and genetic studies are revealing the underlying neuropathology in ADHD. Novel extended-release (ER) MPH formulations now offer drug delivery options to overcome both the short-term actions of immediate-release (IR) MPH and the acute tolerance associated with the first-generation ER-MPH products. These novel MPH products apply proprietary technologies such as OROS (Alza), Diffucaps (Eurand) and SODAS (Elan) to offer both the convenience of once-a-day administration and absorption profiles resembling, to varying degrees, the standard multiple dose schedules of IR-MPH. The pharmacodynamics of the separate MPH enantiomers is in the process of further neuropharmacological characterisation. It is well established that dl-MPH undergoes marked stereoselective metabolism. Although l-MPH exhibits only minimal oral absorption, it may preferentially penetrate the brain, and interacts with ethanol to form the metabolite ethylphenidate. The newly approved resolved enantiomer product d-MPH is now available in an IR formulation, and when administered at one-half the dose to that of the racemate, is purported to produce a longer duration of clinical effect, despite essentially identical pharmacokinetics. A long-acting formulation of d-MPH, which employs the SODAS technology, is in the advanced stages of clinical development.

Methylphenidate blood levels and therapeutic response in children with attention-deficit hyperactivity disorder: I. Effects of different dosing regimens

BACKGROUND AND PURPOSE

Methylphenidate (MPH) is a drug of choice for treating attention-deficit/hyperactivity disorder (ADHD), although its use has been complicated by its short duration of action. The development of ideal long-acting preparations requires detailed understanding of the pharmacokinetic and pharmacodynamic consequences of complex dosing regimens. The purpose of this study was to ascertain if administration paradigms that produce stable or rising MPH levels alter the rate with which MPH is absorbed, and to determine how effectively long-acting administration paradigms compare with thrice daily administration of immediate-release MPH.

METHOD

Forty-eight boys diagnosed with ADHD (mean age 10.6 +/- 1.1 year) participated in this double-blind, parallel group study to evaluate the pharmacokinetics and efficacy and of 1 mg/kg/day MPH administered in five different paradigms and placebo. Objective measures of activity and attention (McLean Motion Attention Test; M-MAT) and plasma measures of d- and l-MPH were obtained hourly during the course of a 12-hour laboratory session.

RESULTS

The rate of absorption and elimination of d-MPH was dependent on the pattern of administration, particularly on the initial bolus concentration. This suggests that d-MPH may act on the gastrointestinal system to slow absorption of additional d-MPH. There were significant differences among regimens on time course and degree of therapeutic response. Pulsatile administration produced greater improvement than escalating levels.

Determinants of adherence to methylphenidate and the impact of poor adherence on maternal and family measures

OBJECTIVE

The aim of this study was to examine the association between adherence to immediate-release methylphenidate (IR MPH) and maternal psychological distress, parenting style, parent- child relationship, and perceived family support.

METHODS

The sample consisted of 307 children with attention-deficit hyperactivity disorder (ADHD) (271 boys and 36 girls), 6-17 years of age, who had been treated with IR MPH for the past 6 months. The measures included the Chinese Health Questionnaire, Parental Bonding Instrument, Family APGAR, and Home Behaviors of the Social Adjustment Inventory for Children and Adolescents.

RESULTS

Reasons for poor adherence (n = 79; 25.7%) included forgetting medication (72.7%), the medication having no effect (20.0%), and refusing medication (12.7%). Increased age and three-times-daily administration were the major predictors for poor adherence to IR MPH. Poor adherence was associated with increased degree of maternal psychological distress, indifferent parenting, maternal overprotection/control, poor family support, decreased interaction with parents, and increased problems at home.

CONCLUSIONS

Findings indicate that multiple daily dosing of MPH increases the likelihood of poor adherence, particularly in adolescents, and that poor adherence is associated with impaired maternal/family process. Once-daily administration of MPH is necessary to improve adherence and to decrease the possible exacerbation of tense parent-child relationships caused by poor drug adherence.