ABSTRACT. Objective. OROS methylphenidate HCL (MPH) is a recently developed long-acting stimulant medication used to treat attention-deficit/hyperactivity disorder (ADHD). This study was conducted to examine dosage effects on ADHD symptoms and stimulant side effects and to explore potential moderating effects of ADHD subtype.Methods. Children with ADHD combined type (ADHD-CT) or predominantly inattentive type (ADHD-PI; n ‫؍‬ 47), ages 5 to 16 years, underwent a placebocontrolled, crossover trial using forced titration with weekly switches at 3 dosage levels. Parent and teacher ratings of ADHD symptoms were used to evaluate efficacy. In addition, vital signs and standardized measures of stimulant side effects were obtained weekly.Results. Parent ratings were more sensitive to treatment effects than teacher ratings. ADHD symptoms and Clinical Global Impressions Severity Index ratings at each dose condition differed significantly from placebo and baseline ratings, which did not differ from one another. For those with ADHD-CT, there was a clear linear dose-response relationship, with clinically significant reductions in ADHD Rating Scale-IV scores occurring in two thirds to three fourths of the subjects during either 36-or 54-mg dose conditions. Children with ADHD-PI, conversely, were more likely to respond optimally to lower doses and derived less benefit from higher doses, with 60% displaying significant improvement on the ADHD Rating Scale-IV at 36 mg or lower. Mild stimulant side effects were reported during placebo and at all dosage levels. With the exception of insomnia and decreased appetite, which were more common at higher doses, parent report of side effects was not related to dose. In addition, younger and smaller children were more likely to display sleep difficulties and decreased appetite at the higher dose levels Although pulse rate increased slightly with increasing dose, there were no dose effects on blood pressure.Conclusions. In children with ADHD-CT, the most common subtype of ADHD, increasing doses of stimulant medication were associated with increased improvement of inattention and hyperactivity symptoms. In children with ADHD-PI, symptom improvement occurred at lower doses and less benefit was derived from higher doses. In both ADHD subtypes, higher doses were associated with parent ratings of increased insomnia and decreased appetite. Pediatrics 2003;112:e404 -e413. URL: http://www.pediatrics.org/cgi/content/full/112/5/e404; attention-deficit/hyperactivity disorder, methylphenidate, pharmacologic treatment.ABBREVIATIONS. ADHD, attention-deficit/hyperactivity disorder; MPH, methylphenidate; DSM-IV, Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition; ADHD-PI, attentiondeficit/hyperactivity disorder predominantly inattentive type; ADD, attention-deficit disorder; ADHD-CT, attention-deficit/hyperactivity disorder combined type; ODD, oppositional defiant disorder; ADHD RS-IV, ADHD Rating Scale-IV: Home Edition; CGI, Clinical Global Impressions Severity Index; SERS, Side Effect R...

Stimulant medications, such as methylphenidate (MPH), are the most commonly used, effective treatment for ADHD. MPH acts primarily by inhibiting the dopamine transporter (DAT), a protein responsible for the reuptake of dopamine from the synapse into presynaptic terminals. We sought to evaluate the relationship between DAT1 3 0 -untranslated region (3 0 -UTR) variable number tandem repeats (VNTR) genotypes and dose response to MPH. Children with ADHD (n ¼ 47), ages 5-16 years (mean ¼ 9.02 years), underwent a 4-week, double-blinded, crossover trial with forced weekly dosage changes. Children were genotyped for the DAT1 VNTR and evaluated on placebo and three dosage levels of OROS s MPH. Parents and clinicians who were blind to genotype and medication status rated ADHD symptoms, impairment, and stimulant side effects each week. Children who were homozygous for the less common, 9-repeat DAT1 3 0 -UTR genotype displayed a distinct dose-response curve from that of the other genotype groups, with an absence of typical linear improvement when the dose was increased from 18 mg to 36 and 54 mg. Further research is needed to determine the mechanisms related to poor response in patients with the 9/9-repeat genotype, and to determine if this group responds differentially to alternative treatments.

clinicaltrials.gov Identifier: NCT00318981.

This pilot study of 23 mothers with attention-deficit/hyperactivity disorder (ADHD) and their offspring with ADHD examined the effects of maternal stimulant medication on observed interactions. Parent-child interactions were observed using a structured protocol before and after mothers underwent a 5-week, double-blind stimulant titration. Despite dramatic effects of medication on adult ADHD symptoms, this small pilot and open label laboratory-based study did not identify maternal stimulant effects on observed parenting or child behavior. Given the documented impairments in parenting displayed by adults with ADHD, behavioral parenting interventions may be needed in conjunction with medication for mothers with ADHD to optimize family outcomes.

Methylphenidate is a first-line therapy for attention deficit hyperactivity disorder, the most prevalent neuropsychiatric disorder of childhood. The compound is a piperidine and the D-threo-isomer is considered the biologically active form. The compound is available in multiple short- and long-acting preparations, having different delivery systems leading to varying kinetics without clear superiority in efficacy or tolerability at the group level. Common adverse effects are insomnia, appetite disturbance, stomach ache, headache and dizziness. Its mechanism of action is linked to the monoamines dopamine and norepinephrine. The compound appears to predominantly increase the synaptic concentration of dopamine, presumably via inhibition of the dopamine transporter DAT1. There also appears to be effects on presynaptic vesicular trafficking and distribution of dopamine. Both immediate- and sustained-release preparations of methylphenidate have proven efficacy in children and adults with attention deficit hyperactivity disorder. Analysis of the National Institutes of Health-sponsored multimodal treatment study of attention deficit hyperactivity disorder supports a combined medication and behavioral therapy approach.