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

INTRODUCTION: Amphetamine preparations are one of the two categories of stimulant medications approved for the treatment of attention deficit hyperactivity disorder (ADHD). Optimal treatment of ADHD aims to reduce core symptoms for as much of the waking hours as possible, leading to longer-acting delivery formats. In addition, the pediatric population commonly has difficulty swallowing pills and manufacturers have developed a variety of options to facilitate this concern. These include chewable tablets, capsules that may be sprinkled on soft food, liquids and transdermal patches. AREAS COVERED: This article reviews the once-daily extended-release preparations currently available for amphetamine compounds, their pharmacodynamics, and common adverse effects. EXPERT OPINION: There is an extensive evidence base supporting use of amphetamine preparations in the treatment of ADHD. Rapid onset of action and a favorable side effect profile make these widely used. The availability of once-daily extended-release chewable tablets, capsules that can be opened and sprinkled, and liquid formulations provides clinicians with multiple options to meet the specific needs of patients with difficulty swallowing whole pills.

Down syndrome patients with pulmonary hypertension have elevated plasma levels of asymmetric dimethylarginine.

Down syndrome (DS) patients have an increased risk of developing pulmonary hypertension (PH). Increased plasma levels of asymmetric dimethylarginine (ADMA) may contribute to vascular dysfunction in adults with idiopathic pulmonary hypertension. Our goal was to test the hypothesis that DS patients with PH have higher plasma levels of ADMA than DS patients without PH. DS patients with definitive PH (n = 6) and DS patients with no evidence of PH (n = 12) were studied. Plasma levels of arginine, ADMA, and nitrite/nitrate (NOx; stable metabolites of nitric oxide (NO)) were measured. Plasma arginine concentration was lower (p < 0.05) in PH patients (23 ± 11 µM) versus non-PH patients (46 ± 24 µM). Plasma ADMA concentration was higher (p < 0.005) in PH patients (18.0 ± 4.2 µM) versus non-PH patients (8.6 ± 5.9 µM). Plasma NOx was lower (p < 0.05) in PH patients (4.5 ± 1.7 µM) versus non-PH patients (8.5 ± 7.3 µM). These results are consistent with ADMA contributing to lower NO production in DS patients with PH and suggest that ADMA levels may be a potential biomarker for PH in DS patients.

Endothelial nitric oxide synthase polymorphisms associated with abnormal nitric oxide production are not over-represented in children with Down syndrome.

OBJECTIVE: Down syndrome patients are at increased risk for developing pulmonary hypertension (PHTN). Nitric oxide (NO) is an important factor for pulmonary vasoreactivity. Various endothelial nitric oxide synthase (eNOS) polymorphisms have been shown to affect NO. The goal of this study was to determine whether there was a difference in prevalence of eNOS polymorphisms between Down syndrome patients vs. non-Down syndrome patients. METHODS: Down syndrome patients were recruited as well as non-Down syndrome patients. Gene polymorphisms for eNOS-3 (GG, GT, TT), eNOS-4 (bb, ba, aa), and eNOS-P (TT, TC, CC) were determined. Three forms of the 3 genes were compared in cross-tabulation tables with Down syndrome patients vs. non-Down syndrome patients and Down syndrome patients with heart defects vs. those without defects. Association was tested with chi-square and significance was set at P < or = .05. RESULTS: Fifty-one Down syndrome patients and 411 controls were studied. Twenty-one Down syndrome patients had heart defects and 6 of these patients had documented PHTN. There was no difference in gender between Down syndrome patients (males 56.9%) and controls (males 50.4%), P = .38. Prevalence of eNOS polymorphisms between Down syndrome patients and controls was not different for the genes (eNOS-3, P = .94; eNOS-4, P = .40; eNOS-P, P = .18). There was no difference in gene polymorphisms between Down syndrome patients with heart defects vs. those without defects (eNOS-3, P = .19; eNOS-4, P = .29; eNOS-P, P = .99). CONCLUSION: Prevalence of various eNOS polymorphisms between Down syndrome patients and controls was not different. Other polymorphisms that are associated with PHTN should be studied to determine whether they may be the cause of the increased risk of PHTN in Down syndrome patients.

Acute and long-term safety and tolerability of risperidone in children with autism.

Treatment-emergent adverse events (AEs) were monitored during an 8-week, double-blind, placebo-controlled trial of risperidone (0.5-3.5 mg/day) in 101 children and adolescents with a lifetime diagnosis of autistic disorder. In addition, 37 placebo nonresponders received open-label risperidone for another 8 weeks. Of all the risperidone responders (n=65), 63 entered an open extension of another 16 weeks (6 months total risperidone exposure), and 32 of them were rerandomized to either continued risperidone therapy (n=16) or gradual replacement with placebo (n=16) over 8 weeks. We collected the following measures of safety and tolerability: (1) laboratory blood assessments (CBC with differential, electrolytes, and liver function tests) and urinalyses, (2) vital signs, (3) Side Effects Review of AEs thought to be associated with risperidone, (4) sleep records, (5) Simpson Angus Neurological Rating Scale (SARS), (6) Abnormal Involuntary Movement Scale (AIMS), and (7) height and weight. No clinically significant changes were found on the lab tests. During the 8-week acute trial, the most common AEs on the Side Effects Review, scored as moderate or higher, were as follows (placebo and risperidone, respectively): Somnolence (12% and 37%), enuresis (29% and 33%), excessive appetite (10% and 33%), rhinitis (8% and 16%), difficulty waking (8% and 12%), and constipation (12% and 10%). "Difficulty falling asleep" and anxiety actually favored the risperidone condition at statistically significant levels. The same AEs tended to recur through 6 months of treatment, although often at reduced levels. Using Centers for Disease Control (CDC) standardized scores, both weight and body mass index (BMI) increased with risperidone during the acute trial (0.5 and 0.6 SDs, respectively, for risperidone; 0.0 and 0.1 SDs, respectively, for placebo) and into open-label extension (0.19 and 0.16 SDs, respectively), although the amount of gain decelerated with time. Extrapyramidal symptoms, as assessed by the SARS, were no more common for drug than placebo, although drooling was reported more often in the risperidone group. There were no differences between groups on the AIMS. Two subjects had seizures (one taking placebo), but these were considered unrelated to active drug. Most AEs were mild to moderate and failed to interfere with therapeutic changes; there were no unanticipated AEs. The side effects of most concern were somnolence and weight gain.

Epidemiology and etiology of autistic spectrum disorders difficult to determine.

The epidemiology of the autistic spectrum disorders is changing. A clear increase in prevalence has been noted during the past 2 decades. What is less clear is the cause for this increase. Multiple factors appear to be responsible. The preponderance of evidence suggests most of the rise in incidence and prevalence is related to changes in diagnostic criteria and greater awareness on the part of both professionals and parents. Proposed theories of causation, which also seek to explain the increase in prevalence, have not been substantiated. Further research is needed to better determine the incidence and prevalence of these disorders and their etiologic factors.