A Randomized, Controlled Laboratory Classroom Study of Serdexmethylphenidate and d-Methylphenidate Capsules in Children with Attention-Deficit/Hyperactivity Disorder

Recent advances in pharmacological management of attention-deficit/hyperactivity disorder: moving beyond stimulants

INTRODUCTION

Attention-deficit/hyperactivity disorder (ADHD) is a common neurobehavioral disorder characterized by impairing inattention and/or hyperactivity and impulsivity in children and adults. Although medications have been available to treat ADHD symptoms for decades, many are stimulant formulations. Stimulants, such as amphetamine and methylphenidate, are available in more than two dozen formulations, but all have similar adverse effects and carry a risk of misuse and dependence.

AREAS COVERED

In the United States (US), several nonstimulants are available to treat ADHD. Two, including atomoxetine and viloxazine extended-release (ER), are approved by the Food and Drug Administration for the treatment of ADHD in children and adults. Two others, clonidine ER and guanfacine ER, are only approved for children and adolescents in the US. Several other compounds are under investigation. Drugs in Phase 3 trials include centanafadine, solriamfetol, and L-threonic acid magnesium salt. Efficacy and safety data for nonstimulants is presented.

EXPERT OPINION

Although many effective formulations for the treatment of ADHD are available, more than 33% of children and 50% of adults discontinue treatment during the first year. The lack of individual drug response and tolerability are reasons many stop treatment. The development of new nonstimulants may offer hope for patients who need medication alternatives.

From Consensus Statement to Pills to Pixels: New Innovations in Attention-Deficit/Hyperactivity Disorder Care

Objectives: This review aims to present recent innovations and advancements in attention-deficit/hyperactivity disorder (ADHD) care, encompassing international consensus statement, new medication formulations, digital therapeutics, and neurostimulation devices. Methods: A comprehensive literature search of relevant articles published in the past five years was conducted, emphasizing the evidence base, efficacy, safety, and practical implications of these advancements. Results: The World Federation of ADHD Consensus Statement offers an updated diagnostic and treatment framework rooted in global scientific evidence. There are several newer ADHD medication formulations, including a nonstimulant (Viloxazine extended release) and the first transdermal amphetamine patch approved to treat ADHD. These options offer some unique benefits to personalize treatment based on symptom profile, lifestyle, preferences, and response. Digital tools offer additional means to restructure environments for individuals with ADHD, reducing impairment and reliance on others. In addition, digital therapeutics enhance access, affordability, personalization, and feasibility of ADHD care, complementing or augmenting existing interventions. Trigeminal nerve stimulation emerges as a well-tolerated nonpharmacological, device-based treatment for pediatric ADHD, with initial trials indicating effect sizes comparable to nonstimulant medications. Conclusions: These innovations in ADHD care represent clinically significant new treatment options and opportunities for personalized care. Health care professionals should integrate these developments into clinical practice, mindful of individual patient and family needs and preferences. Future research should assess long-term outcomes, cost-effectiveness, and acceptability of these innovations.

Serdexmethylphenidate/dexmethylphenidate for children with attention-deficit/hyperactivity disorder: dose optimization from a laboratory classroom study

Objective

To evaluate treatment responder rate using the Attention-Deficit/Hyperactivity Disorder Rating Scale-5 (ADHD-RS-5) score based on optimized dose level of serdexmethylphenidate/dexmethylphenidate (SDX/d-MPH) and changes in ADHD severity in children (aged 6-12 years) with ADHD.

Methods

During a 21-day dose-optimization phase, 155 patients initiated treatment with 39.2/7.8 mg SDX/d-MPH in the first week and then were titrated to an optimum dose; 5 patients were downtitrated to 26.1/5.2 mg, 76 were uptitrated to 52.3/10.4 mg, and 69 remained at 39.2/7.8 mg during the following 2 weeks. Responder threshold values were 30% and 50% based on the percent change from baseline (day 0) to days 7, 14, and 21 in the ADHD-RS-5 score. The Conners 3rd Edition-Parent score was used to assess weekly changes in ADHD severity during the dose-optimization and treatment phases.

Results

Of the 5 subjects whose dose was optimized at 26.1/5.2 mg, ≥80% across all days had ≥50% responder rate. Of the 69 subjects whose dose was optimized at 39.2/7.8 mg, 81.2% had ≥50% responder rate by day 21. Of the 76 subjects whose dose was optimized to 52.3/10.4 mg, 72.4% had ≥50% responder rate by day 21. Changes in ADHD severity, based on mean Conners 3rd Edition-Parent scores, improved from baseline at each visit during dose optimization for each subscale. At the dose-optimization phase, Conners 3rd Edition-Parent scores improved from baseline for SDX/d-MPH in all subscales.

Conclusion

A high percentage of subjects were responders upon reaching their final optimized dose. SDX/d-MPH demonstrated significant reductions in ADHD severity in children based on the Conners 3rd Edition-Parent scores. Determining the optimal dosage of SDX/d-MPH and its effect on ADHD severity could enable the development of a more clinically relevant treatment regimen in children with ADHD.

A Comprehensive Review of Novel FDA-Approved Psychiatric Medications (2018-2022)

Mental health disorders are among the top leading causes of disease burden worldwide and many patients have high levels of treatment resistance. Even though medications offer improvement to some patients, antidepressants are only effective in about half of those treated, and schizophrenia is treatment-refractory in about one-third of patients. One way to combat this disparity is to improve medication development and discovery for psychiatric disorders through evidence-based research. Recently, most psychiatric medications approved by the United States Food and Drug Administration (FDA) are for increased tolerability or extended release. Because of the slow, incremental progress, there is a pressing need to explore novel medications with new indications or mechanisms of action to treat the expanding population with mental disorders, especially in those who are fully or partially recalcitrant to first-line medication options. This review aims to present the newest FDA medications with new indications, establish the clinical need for each, and discuss future directions in drug development. We searched and reviewed novel psychiatric medications approved by the FDA from 2018 to 2022. We then analyzed each medication in the United States Clinical Trials Registry and gathered updated results for efficacy and safety information. We also searched PubMed/MEDLINE (Medical Literature Analysis and Retrieval System Online), Scopus, Web of Science, Elsevier, and Google Scholar to understand how these new indications met current clinical needs. Finally, we inquired about related technological implications that will lead the field of psychopharmacology now and in the years to come. We found 12 novel psychiatric medications approved by the FDA from 2018 to 2022, representing a very small percentage of the total FDA approvals during that period. These psychiatric medications with novel mechanisms or improved efficacy and safety  are expected to provide further options for treating mental health disorders; promising results will lead to new patterns of research.

Stimulant prodrugs: A pharmacological and clinical assessment of their role in treating ADHD and binge-eating disorder

In this review, we critically evaluate the contribution of prodrugs to treating two related psychiatric disorders, attention-deficit hyperactivity disorder (ADHD) and binge-eating disorder (BED). ADHD is characterized by inattentiveness, distractibility, impulsiveness, and hyperactivity. BED is also an impulse-control disorder which leads to frequent, compulsive episodes of excessive eating (binges). Lisdexamfetamine (LDX; prodrug of d-amphetamine) is approved to treat both ADHD and BED. Serdexmethylphenidate (SDX; prodrug of d-threo-methylphenidate) is not clinically approved as monotherapy but, in a fixed-dose combination with immediate release d-threo-methylphenidate (Azstarys™), SDX is approved for managing ADHD in children/adolescents. The pharmacological actions of a stimulant mediate both its efficacy and side-effects. Therefore, daily management of ADHD or BED to maintain optimum efficacy and tolerability places highly restrictive requirements on the pharmacokinetic/pharmacodynamic (PK/PD) characteristics of stimulant medications, especially prodrugs. Prodrugs must have good bioavailability and rapid metabolism to provide therapeutic efficacy soon after morning dosing combined with providing stimulant coverage throughout the day/evening. A wide selection of dosages and linear PK for the prodrug and its active metabolite are essential requirements for treatment of these conditions. The proposed neurobiological causes of ADHD and BED are described. The chemical, pharmacological and PK/PD properties responsible for the therapeutic actions of the prodrugs, LDX and SDX, are compared and contrasted. Finally, we critically assess their contribution as ADHD and BED medications, including advantages over their respective active metabolites, d-amphetamine and d-threo-methylphenidate, and also their potential for misuse and abuse.

Pediatric attention deficit hyperactivity disorder (ADHD): 2022 updates on pharmacological management

INTRODUCTION

Pediatric attention-deficit disorder (ADHD) impacts a significant percentage of the population world-wide. Pharmacologic treatments have been shown to be safe and effective for managing symptoms. Various medication formulations exist, and new medication agents are continually approved each year.

AREAS COVERED

This article offers an overview of ADHD, an overview of both stimulant and non-stimulant medication options as well as an overview of stimulant misuse. It explores the medication mechanisms of action and side effect profiles, as well as offering an in-depth summary of the novel agents recently approved and soon-to-be approved for use in youth. PubMed and Medline were utilized. Search terms included children, adolescents, ADHD, and medication. FDA package inserts were reviewed for all medications.

EXPERT OPINION

New formulations of medications include an evening administered, extended, and delayed-release form of methylphenidate (DR/ER MPH), a methylphenidate pro-drug (serdexmethylphenidate) and an amphetamine patch. The availability of a new SNRI (selective norepinephrine reuptake inhibitor), viloxazine extended-release (VER), and the pending approval of a triple reuptake inhibitor (centanafadine) provides welcome additions to the prescriber's toolbox.

Serdexmethylphenidate/dexmethylphenidate effects on sleep in children with attention-deficit/hyperactivity disorder

Introduction

Sleep-related problems are common in children with attention-deficit/hyperactivity disorder (ADHD). Sleep disorders are also side effects of all stimulant ADHD medications. Serdexmethylphenidate/dexmethylphenidate (SDX/d-MPH) is a once-daily treatment approved for patients age 6 years and older with ADHD. In this analysis, sleep behavior was assessed during SDX/d-MPH treatment in children with ADHD.

Methods

In a 12-month, dose-optimized, open-label safety study in 6- to 12-year-old participants (NCT03460652), a secondary endpoint was assessment of sleep behavior based on the Children's Sleep Habits Questionnaire (CSHQ) consisting of 8 sleep domains (bedtime resistance, sleep onset delay, sleep duration, sleep anxiety, night wakings, parasomnias, sleep-disordered breathing, and daytime sleepiness). This post hoc analysis examined the individual sleep domains in the 12-month safety study.

Results

Of 282 participants enrolled, 238 were included in the sleep analysis. At baseline, mean (SD) CSHQ total sleep disturbance score was 53.4 (5.9). After 1 month of treatment, the mean (SD) CSHQ total score significantly decreased to 50.5 (5.4); least-squares mean change from baseline was -2.9 (95% CI: -3.5 to -2.4; p < 0.0001) and remained decreased up to 12 months. Mean sleep-score improvements from baseline to 12 months were statistically significant (p < 0.0001) for 5 of 8 sleep domains, including bedtime resistance, sleep anxiety, night wakings, parasomnias, and daytime sleepiness. Parasomnias and daytime sleepiness sleep domains showed the greatest mean improvement from baseline to 12 months. Sleep onset delay and sleep duration scores increased from baseline to 12 months. No statistically significant worsening occurred from baseline in sleep duration and sleep-disordered breathing domains; however, worsening of sleep onset delay was statistically significant.

Conclusion

In this analysis of children taking SDX/d-MPH for ADHD, sleep problems did not worsen based on the mean CSHQ total sleep disturbance score. Statistically significant improvements in most CSHQ sleep domains were observed after 1 month and lasted for up to 12 months of treatment.

Evaluating serdexmethylphenidate and dexmethylphenidate capsules as a once-daily treatment option for ADHD

INTRODUCTION

Attention deficit/hyperactivity disorder (ADHD) is a common behavioral disorder which is best treated through a combination of medication and behavioral therapy, with stimulant medications serving as a first-line treatment approach. Serdexmethylphenidate (SDX), a prodrug of dexmethylphenidate (d-MPH), a commonly utilized stimulant medication, has recently received approval and is marketed in the U.S.A.

AREAS COVERED

This review summarizes peer-reviewed literature on SDX published between 2021-2023 and a review of data available from ClinicalTrials.gov.

EXPERT OPINION

SDX represents a new option for treatment for ADHD. It is unique in its prodrug design and achieves a relatively extended duration of action in comparison to other stimulant formulations. Although the research is relatively limited thus far, early data suggests it to be a safe medication to consider with side effects being similar to other stimulant medications. Its prodrug design is useful in potentially serving as a deterrent to intentional parenteral abuse and its ability to be opened and sprinkled makes it an option for those individuals with ADHD who might be unable to swallow pills.

Methylphenidate for children and adolescents with attention deficit hyperactivity disorder (ADHD)

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is one of the most commonly diagnosed and treated psychiatric disorders in childhood. Typically, children and adolescents with ADHD find it difficult to pay attention and they are hyperactive and impulsive. Methylphenidate is the psychostimulant most often prescribed, but the evidence on benefits and harms is uncertain. This is an update of our comprehensive systematic review on benefits and harms published in 2015.

OBJECTIVES

To assess the beneficial and harmful effects of methylphenidate for children and adolescents with ADHD.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, three other databases and two trials registers up to March 2022. In addition, we checked reference lists and requested published and unpublished data from manufacturers of methylphenidate.

SELECTION CRITERIA

We included all randomised clinical trials (RCTs) comparing methylphenidate versus placebo or no intervention in children and adolescents aged 18 years and younger with a diagnosis of ADHD. The search was not limited by publication year or language, but trial inclusion required that 75% or more of participants had a normal intellectual quotient (IQ > 70). We assessed two primary outcomes, ADHD symptoms and serious adverse events, and three secondary outcomes, adverse events considered non-serious, general behaviour, and quality of life.

DATA COLLECTION AND ANALYSIS

Two review authors independently conducted data extraction and risk of bias assessment for each trial. Six review authors including two review authors from the original publication participated in the update in 2022. We used standard Cochrane methodological procedures. Data from parallel-group trials and first-period data from cross-over trials formed the basis of our primary analyses. We undertook separate analyses using end-of-last period data from cross-over trials. We used Trial Sequential Analyses (TSA) to control for type I (5%) and type II (20%) errors, and we assessed and downgraded evidence according to the GRADE approach.

MAIN RESULTS

We included 212 trials (16,302 participants randomised); 55 parallel-group trials (8104 participants randomised), and 156 cross-over trials (8033 participants randomised) as well as one trial with a parallel phase (114 participants randomised) and a cross-over phase (165 participants randomised). The mean age of participants was 9.8 years ranging from 3 to 18 years (two trials from 3 to 21 years). The male-female ratio was 3:1. Most trials were carried out in high-income countries, and 86/212 included trials (41%) were funded or partly funded by the pharmaceutical industry. Methylphenidate treatment duration ranged from 1 to 425 days, with a mean duration of 28.8 days. Trials compared methylphenidate with placebo (200 trials) and with no intervention (12 trials). Only 165/212 trials included usable data on one or more outcomes from 14,271 participants. Of the 212 trials, we assessed 191 at high risk of bias and 21 at low risk of bias. If, however, deblinding of methylphenidate due to typical adverse events is considered, then all 212 trials were at high risk of bias.

PRIMARY OUTCOMES

methylphenidate versus placebo or no intervention may improve teacher-rated ADHD symptoms (standardised mean difference (SMD) -0.74, 95% confidence interval (CI) -0.88 to -0.61; I² = 38%; 21 trials; 1728 participants; very low-certainty evidence). This corresponds to a mean difference (MD) of -10.58 (95% CI -12.58 to -8.72) on the ADHD Rating Scale (ADHD-RS; range 0 to 72 points). The minimal clinically relevant difference is considered to be a change of 6.6 points on the ADHD-RS. Methylphenidate may not affect serious adverse events (risk ratio (RR) 0.80, 95% CI 0.39 to 1.67; I² = 0%; 26 trials, 3673 participants; very low-certainty evidence). The TSA-adjusted intervention effect was RR 0.91 (CI 0.31 to 2.68).

SECONDARY OUTCOMES

methylphenidate may cause more adverse events considered non-serious versus placebo or no intervention (RR 1.23, 95% CI 1.11 to 1.37; I² = 72%; 35 trials 5342 participants; very low-certainty evidence). The TSA-adjusted intervention effect was RR 1.22 (CI 1.08 to 1.43). Methylphenidate may improve teacher-rated general behaviour versus placebo (SMD -0.62, 95% CI -0.91 to -0.33; I² = 68%; 7 trials 792 participants; very low-certainty evidence), but may not affect quality of life (SMD 0.40, 95% CI -0.03 to 0.83; I² = 81%; 4 trials, 608 participants; very low-certainty evidence).

AUTHORS' CONCLUSIONS

The majority of our conclusions from the 2015 version of this review still apply. Our updated meta-analyses suggest that methylphenidate versus placebo or no-intervention may improve teacher-rated ADHD symptoms and general behaviour in children and adolescents with ADHD. There may be no effects on serious adverse events and quality of life. Methylphenidate may be associated with an increased risk of adverse events considered non-serious, such as sleep problems and decreased appetite. However, the certainty of the evidence for all outcomes is very low and therefore the true magnitude of effects remain unclear. Due to the frequency of non-serious adverse events associated with methylphenidate, the blinding of participants and outcome assessors is particularly challenging. To accommodate this challenge, an active placebo should be sought and utilised. It may be difficult to find such a drug, but identifying a substance that could mimic the easily recognised adverse effects of methylphenidate would avert the unblinding that detrimentally affects current randomised trials. Future systematic reviews should investigate the subgroups of patients with ADHD that may benefit most and least from methylphenidate. This could be done with individual participant data to investigate predictors and modifiers like age, comorbidity, and ADHD subtypes.

Epilepsy and Attention Deficit Hyperactivity Disorder: Connection, Chance, and Challenges

Comorbidities are common in children with epilepsy, with nearly half of the patients having at least one comorbidity. Attention deficit hyperactivity disorder (ADHD) is a psychiatric disorder characterized by hyperactivity and inattentiveness level disproportional to the child’s developmental stage. The burden of ADHD in children with epilepsy is high and can adversely affect the patients’ clinical outcomes, psychosocial aspects, and quality of life. Several hypotheses were proposed to explain the high burden of ADHD in childhood epilepsy; the well-established bidirectional connection and shared genetic/non-genetic factors between epilepsy and comorbid ADHD largely rule out the possibility of a chance in this association. Stimulants are effective in children with comorbid ADHD, and the current body of evidence supports their safety within the approved dose. Nonetheless, safety data should be further studied in randomized, double-blinded, placebo-controlled trials. Comorbid ADHD is still under-recognized in clinical practice. Early identification and management of comorbid ADHD are crucial to optimize the prognosis and reduce the risk of adverse long-term neurodevelopmental outcomes. The identification of the shared genetic background of epilepsy and ADHD can open the gate for tailoring treatment options for these patients through precision medicine.

Safety and Tolerability of Serdexmethylphenidate/Dexmethylphenidate Capsules in Children with Attention-Deficit/Hyperactivity Disorder: A 12-Month, Open-Label Safety Study

Objective: Serdexmethylphenidate/dexmethylphenidate (SDX/d-MPH) is approved for the treatment of patients aged ≥6 years with attention-deficit/hyperactivity disorder (ADHD). A pivotal double-blind (DB) study of children aged 6-12 years with ADHD demonstrated efficacy for ADHD with good tolerability. In this study, we assessed the safety and tolerability of daily oral SDX/d-MPH for up to 1 year in children with ADHD. Methods: This was a dose-optimized, open-label safety study with SDX/d-MPH in children aged 6-12 years with ADHD that included subjects who successfully completed the DB study (rollover) and new subjects. The study consisted of a 30-day screening phase, a dose optimization phase for new subjects only, a 360-day treatment phase, and follow-up. Adverse events (AEs) were assessed from the first day of SDX/d-MPH administration to the end of the study. During the treatment phase, ADHD Rating Scale-5 (ADHD-RS-5) and Clinical Global Impressions-Severity (CGI-S) scale assessments were used to evaluate ADHD severity. Results: Of the 282 subjects enrolled (70 rollover; 212 new), 28 discontinued treatment in the dose optimization phase and 254 entered the treatment phase. By study completion, 127 had discontinued and 155 had completed the study. The treatment-phase safety population included all enrolled subjects who received ≥1 dose of study drug and had ≥1 postdose safety assessment. Of 238 subjects assessed in the treatment-phase safety population, 143 (60.1%) had ≥1 treatment-emergent adverse events (TEAEs), and 36 (15.1%), 95 (39.9%), and 12 (5.0%) had mild, moderate, or severe TEAEs, respectively. The most common TEAEs were decreased appetite (18.5%), upper respiratory tract infection (9.7%), nasopharyngitis (8.0%), decreased weight (7.6%), and irritability (6.7%). There were no clinically meaningful trends in electrocardiograms, cardiac events, or blood pressure events, and none led to discontinuation. Two subjects had eight serious AEs that were unrelated to treatment. There were overall reductions in ADHD symptoms and severity as assessed by ADHD-RS-5 and CGI-S during the treatment phase. Conclusions: In this 1-year study, SDX/d-MPH was found to be safe and well tolerated and comparable with other methylphenidate products, with no unexpected safety findings. SDX/d-MPH also showed sustained efficacy during the 1-year treatment period. ClinicalTrials.gov identifier: NCT03460652.

Early Morning ADHD Symptoms and Functional Impairment: Impact on Patients and Caregivers, and Pharmacological Approaches to Management

Attention-deficit/hyperactivity disorder (ADHD) is a common and impairing mental disorder. Individuals with ADHD typically experience symptoms from awakening throughout the entire day, contributing to impaired function at home, at school, and in the workplace. Treatment is available to address the symptoms of ADHD; however, the extent to which treatments afford improved function remains less clear. Impaired function in children and adolescents, particularly in the early morning where multiple tasks must be completed, from getting out of bed, and having breakfast to leaving for school on time, is common even among stimulant-treated children, and can increase stress upon caregivers and family members. Herein, we present a narrative review on early morning functioning impairment in children and adolescents with ADHD, its impact on caregivers, the rating scales available for clinicians to identify the degree of early morning functioning impairment, and the efficacy of currently available treatments in providing functional improvements to patients with ADHD during the early morning, identifying that only treatments that are available upon awakening have been shown to statistically separate from placebo for early morning functioning improvement.

The Latest FDA-Approved Pharmaceuticals Containing Fragments of Tailor-Made Amino Acids and Fluorine

Nowadays, the selective introduction of fluorine into bioactive compounds is a mature strategy in the design of drugs allowing to increase efficiency, biological half-life and bio-absorption. On the other hand, amino acids (AAs) represent one of the most ubiquitious classes of naturally occurring organic compounds, which are found in over 40% of newly marked small-molecule pharmaceutical drugs and medical formulations. The primary goal of this work is to underscore two major trends in the design of modern pharmaceuticals. The first is dealing with the unique structural characteristics provided by the structure of amino acids featuring an abundance of functionality and the presence of a stereogenic center, all of which bodes well for the successful development of targeted bioactivity. The second is related to fine-tuning the desired activity and pharmacokinetics by selective introduction of fluorine. Historically, both trends were developed separately as innovative and prolific approaches in modern drug design. However, in recent decades, these approaches are clearly converging leading to an ever-increasing number of newly approved pharmaceuticals containing both structural features of amino acids and fluorine.

A year in pharmacology: new drugs approved by the US Food and Drug Administration in 2021

The second year of the COVID-19 pandemic had no adverse effect on the number of new drug approvals by the US Food and Drug Administration (FDA). Quite the contrary, with a total of 50 new drugs, 2021 belongs to the most successful FDA years. We assign these new drugs to one of three levels of innovation: (1) first drug against a condition ("first-in-indication"), (2) first drug using a novel molecular mechanism ("first-in-class"), and (3) "next-in-class", i.e., a drug using an already exploited molecular mechanism. We identify 21 first-in-class, 28 next-in-class, and only one first-in-indication drugs. By treatment area, the largest group is once again cancer drugs, many of which target specific genetic alterations. Every second drug approved in 2021 targets an orphan disease, half of them being cancers. Small molecules continue to dominate new drug approvals, followed by antibodies and non-antibody biopharmaceuticals. In 2021, the FDA continued to approve drugs without strong evidence of clinical effects, best exemplified by the aducanumab controversy.

Updates in Pharmacologic Strategies in Adult Attention-Deficit/Hyperactivity Disorder

Attention-deficit/hyperactivity disorder (ADHD) significantly worsens quality of life and long-term functional outcomes in adults. Individual impairments in adults with ADHD can be further contextualized within considerable costs to society at large. Food and Drug Administration (FDA) approved stimulants and nonstimulant medications can significantly improve ADHD symptoms in adults. In the past 2 decades, the United States FDA has expanded approval of pharmacotherapeutic options for adult ADHD. However, limitations still persist in available psychotropics for certain patient populations such as those with comorbid substance use or cardiovascular illness. Clinicians therefore must appreciate several ongoing investigations into medications with unique mechanisms of action. This article reviews the current FDA approved and emerging medication options while providing guidelines for pharmacologic management of adult ADHD.

Dose Proportionality and Steady-State Pharmacokinetics of Serdexmethylphenidate/Dexmethylphenidate, a Novel Prodrug Combination to Treat Attention-Deficit/Hyperactivity Disorder

Objective: The study was designed to determine (1) the pharmacokinetic (PK) profile of dexmethylphenidate (d-MPH) after oral administration of three dosage strengths of a new treatment containing d-MPH and a novel prodrug, serdexmethylphenidate (SDX); (2) the dose proportionality of the different SDX/d-MPH dosages; and (3) the steady-state PK profile of d-MPH and SDX after multiple dosing of SDX/d-MPH. Methods: Twenty-three healthy volunteers (aged 18-55 years) under fasted conditions received in a crossover design SDX/d-MPH 26.1/5.2 mg (Treatment A), 39.2/7.8 mg (Treatment B), and 52.3/10.4 mg (Treatment C) for a total d-MPH hydrochloride equivalent dose of 20, 30, and 40 mg, respectively. After a 96-hour washout period, all participants received four consecutive daily doses of SDX/d-MPH 52.3/10.4 mg. Blood samples were collected for measurement of plasma d-MPH and SDX and for PK analysis. Results: Administration of all three doses of SDX/d-MPH resulted in a rapid rise and slow decline in the plasma concentration of d-MPH. For Treatments A, B, and C, mean (± standard deviation) maximum concentrations (C_max) were 7.1 ± 2.1, 9.8 ± 2.8, and 13.8 ± 3.8 ng/mL, and overall exposures (AUC_0-last) were 97.2 ± 28.8, 142.5 ± 41.2, and 199.8 ± 57.2 h*ng/mL, respectively. Dose-normalized C_max, AUC_0-last, and AUC_0-inf for d-MPH were similar when comparing the high and low doses versus the middle dose. Power model regression analysis revealed that C_max and AUC_0-inf proportionally increased with an increase in SDX/d-MPH dose. In the multiple-dose study, d-MPH reached steady state before the third dose, and SDX after the first dose. Conclusion: The PK profile of SDX/d-MPH is characterized by a rapid rise and a gradual decline in d-MPH concentration, with proportional C_max and AUC_0-inf across doses. The PK attributes of SDX/d-MPH may optimize symptom control from early morning to early evening, while the demonstrated dose proportionality may facilitate initial dose titration and ongoing dose adjustment.