Prescription Stimulant Use During Pregnancy and Risk of Neurodevelopmental Disorders in Children

Importance

Use of medications for attention-deficit/hyperactivity disorder (ADHD) during pregnancy is increasing in the US. Whether exposure to these medications in utero impacts the risk of neurodevelopmental disorders in children is uncertain.

Objective

To evaluate the association of childhood neurodevelopmental disorders with in utero exposure to stimulant medications for ADHD.

Design, Setting, and Participants

This cohort study included health care utilization data from publicly insured (Medicaid data from 2000 to 2018) and commercially insured (MarketScan Commercial Claims Database data from 2003 to 2020) pregnant individuals aged 12 to 55 years in the US with enrollment from 3 months prior to pregnancy through 1 month after delivery, linked to children. Children were monitored from birth until outcome diagnosis, disenrollment, death, or end of the study (December 2018 for Medicaid and December 2020 for MarketScan).

Exposures

Dispensing of amphetamine/dextroamphetamine or methylphenidate in the second half of pregnancy.

Main Outcomes and Measures

Autism spectrum disorder, ADHD, and a composite of any neurodevelopmental disorder were defined using validated algorithms. Hazard ratios were estimated comparing amphetamine/dextroamphetamine and methylphenidate to no exposure.

Results

The publicly insured cohort included 2 496 771 stimulant-unexposed, 4693 amphetamine/dextroamphetamine-exposed, and 786 methylphenidate-exposed pregnancies with a mean (SD) age of 25.2 (6.0) years. The commercially insured cohort included 1 773 501 stimulant-unexposed, 2372 amphetamine/dextroamphetamine-exposed, and 337 methylphenidate-exposed pregnancies with a mean (SD) age of 31.6 (4.6) years. In unadjusted analyses, amphetamine/dextroamphetamine and methylphenidate exposure were associated with a 2- to 3-fold increased risk of the neurodevelopmental outcomes considered. After adjustment for measured confounders, amphetamine/dextroamphetamine exposure was not associated with any outcome (autism spectrum disorder: hazard ratio [HR], 0.80; 95% CI, 0.56-1.14]; ADHD: HR, 1.07; 95% CI, 0.89-1.28; any neurodevelopmental disorder: HR, 0.91; 95% CI, 0.81-1.28). Methylphenidate exposure was associated with an increased risk of ADHD (HR, 1.43; 95% CI, 1.12-1.82]) but not other outcomes after adjustment (autism spectrum disorder: HR, 1.06; 95% CI, 0.62-1.81; any neurodevelopmental disorder: HR, 1.15; 95% CI, 0.97-1.36). The association between methylphenidate and ADHD did not persist in sensitivity analyses with stricter control for confounding by maternal ADHD.

Conclusions and Relevance

The findings in this study suggest that amphetamine/dextroamphetamine and methylphenidate exposure in utero are not likely to meaningfully increase the risk of childhood neurodevelopmental disorders.

Assessment of lisdexamfetamine on executive function in rats: A translational cognitive research

Executive function, including working memory, attention and inhibitory control, is crucial for decision making, thinking and planning. Lisdexamfetamine, the prodrug of d-amphetamine, has been approved for treating attention-deficit hyperactivity disorder and binge eating disorder, but whether it improves executive function under non-disease condition, as well as the underlying pharmacokinetic and neurochemical properties, remains unclear. Here, using trial unique non-matching to location task and five-choice serial reaction time task of rats, we found lisdexamfetamine (p.o) enhanced spatial working memory and sustained attention under various cognitive load conditions, while d-amphetamine (i.p) only improved these cognitive performances under certain high cognitive load condition. Additionally, lisdexamfetamine evoked less impulsivity than d-amphetamine, indicating lower adverse effect on inhibitory control. In vivo pharmacokinetics showed lisdexamfetamine produced a relative stable and lasting release of amphetamine base both in plasma and in brain tissue, whereas d-amphetamine injection elicited rapid increase and dramatical decrease in amphetamine base levels. Microdialysis revealed lisdexamfetamine caused lasting release of dopamine within the medial prefrontal cortex (mPFC), whereas d-amphetamine produced rapid increase followed by decline to dopamine level. Moreover, lisdexamfetamine elicited more obvious efflux of noradrenaline than that of d-amphetamine. The distinct neurochemical profiles may be partly attributed to the different action of two drugs to membranous catecholamine transporters level within mPFC, detecting by Western Blotting. Taken together, due to its certain pharmacokinetic and catecholamine releasing profiles, lisdexamfetamine produced better pharmacological action to improving executive function. Our finding provided valuable evidence on the ideal pharmacokinetic and neurochemical characteristics of amphetamine-type psychostimulants in cognition enhancement.

d-Amphetamine Transdermal System in Treatment of Children and Adolescents with Attention-Deficit/Hyperactivity Disorder: Secondary Endpoint Results and Post Hoc Effect Size Analyses from a Pivotal Trial

Objectives: Amphetamines are a preferred treatment for attention-deficit/hyperactivity disorder (ADHD), with the dextroamphetamine transdermal system (d-ATS) providing an alternative to oral formulations. A pivotal trial of d-ATS in children and adolescents with ADHD met primary and key secondary endpoints. This analysis reports additional endpoints and safety findings from the pivotal trial and evaluates effect size and number needed to treat (NNT) for d-ATS. Methods: In this study, a 5-week, open-label dose-optimization period (DOP) preceded a 2-week, randomized, crossover double-blind treatment period (DBP). Eligible patients received d-ATS 5 mg during the DOP, with weekly evaluations for increase to 10, 15, and 20 mg (equivalent to labeled doses of 4.5, 9, 13.5, and 18 mg/9 hours, respectively) until reaching and maintaining the optimal dose, which was utilized for the DBP. Secondary endpoints included assessment of Attention-Deficit/Hyperactivity Disorder Rating Scale IV (ADHD-RS-IV), Conners' Parent Rating Scale Revised Short Form (CPRS-R:S), and Clinical Global Impression (CGI) scores. NNT was calculated for ADHD-RS-IV and CGI-Improvement (CGI-I). Safety assessments included treatment-emergent adverse events (TEAEs) and dermal safety. Results: In total, 110 patients entered the DOP, with 106 patients randomized (DBP). During the DBP, the least-squares mean (95% confidence interval) difference for d-ATS versus placebo in ADHD-RS-IV total score was -13.1 (-16.2 to -10.0; p < 0.001), with effect size of 1.1 and NNT of 3 for ADHD-RS-IV remission, ≥30% improvement, and ≥50% improvement. Significant differences between placebo and d-ATS were also observed for CPRS-R:S and CGI-I scales (p < 0.001), with NNT of 2 for CGI-I response. Most TEAEs were mild or moderate, with three leading to study discontinuation in the DOP and none in the DBP. No patients discontinued due to dermal reactions. Conclusions: d-ATS was effective in treating ADHD in children and adolescents, meeting all secondary endpoints, with a large effect size and NNT of 2-3 to achieve a clinically meaningful response. d-ATS was safe and well tolerated, with minimal dermal reactions. Clinical Trial Registration: NCT01711021.

Real-World Efficacy and Safety of Extended-Release Methylphenidate (PRC-063) in the Treatment of ADHD in Pediatric and Adult Subjects: Results of a Phase IV Multicenter Comparison With Lisdexamfetamine Dimesylate

OBJECTIVE

To evaluate the real-world efficacy, safety, and functional outcomes of PRC-063 (multilayer-release methylphenidate) versus lisdexamfetamine (LDX) in ADHD subjects in a phase IV, open-label study.

METHOD

The primary endpoint was the change in the ADHD-DSM-5 Rating Scale (ADHD-5-RS) total score from baseline to Month 4. Secondary endpoints included a non-inferiority comparison between PRC-063 and LDX and measures of functioning and evening behavior.

RESULTS

One hundred forty-three pediatric and 112 adult subjects were enrolled. Mean ADHD-5-RS scores (standard deviation) were reduced in pediatric (-16.6 [10.4]) and adult (-14.8 [10.6]) subjects treated with PRC-063 (p < .001). PRC-063 was non-inferior to LDX in the pediatric population but not in the adult population. Significant improvements were demonstrated in quality of life and functionality. Both medications were well-tolerated; more adverse events led to study discontinuation in pediatric subjects treated with LDX versus PRC-063.

CONCLUSION

PRC-063 and LDX significantly improved ADHD symptomatology and functioning and were well-tolerated.

Investigating sex differences and the effect of drug exposure order in the sensory reward-enhancing effects of nicotine and d-amphetamine alone and in combination

Nicotine enhances the rewarding effects of other environmental stimuli; this reward-enhancement encourages and maintains nicotine consumption. Nicotine use precedes other psychostimulant use, but receiving a stimulant prescription also predicts future smoking. Previously, no study has investigated effects of drug exposure order in reward-enhancement, nor with nicotine and d-amphetamine. Thus, we aimed to investigate how drug exposure order impacted the reward-enhancing effects of nicotine and d-amphetamine, alone and in combination. We used 20 male and 20 female Sprague-Dawley rats. Enhancement was investigated within-subjects by examining responding maintained by a visual stimulus reinforcer following a pre-session injection of either d-amphetamine (Sal, 0.1, 0.3, or 0.6 mg/kg) or nicotine (Sal, 0.03, 0.06, 0.1, 0.3 mg/kg). Twenty rats (10 M, 10 F) completed enhancement testing with nicotine before d-amphetamine. The other 20 rats (10 M, 10 F) completed testing with d-amphetamine before nicotine. Following these phases, rats were then given two pre-session injections: one of d-amphetamine (Sal, 0.1, 0.3, or 0.6 mg/kg) and another of nicotine (Sal, 0.03, 0.06, 0.1, or 0.3 mg/kg). Experiencing amphetamine before nicotine increased reward-enhancing effects of nicotine. Females exhibited greater effects of d-amphetamine on reward-enhancement, with no effect of exposure order. During the interaction phase, receiving nicotine before amphetamine enhanced the interaction between nicotine and d-amphetamine for females whereas amphetamine before nicotine heightened this interaction for males. From this, prior and current amphetamine use, in addition to sex, should be considered when treating nicotine dependency and when examining factors driving poly-substance use involving nicotine and d-amphetamine. Keywords: Adderall, ADHD, Dexedrine, operant, smoking, polysubstance use.

Bilateral Acute Angle Closure in a Pediatric Patient Taking Lisdexamfetamine Dimesylate (Vyvanse)

Attention-deficit/hyperactivity disorder is commonly treated with amphetamines as first line therapy. Rare case reports have shown amphetamines are associated with open angle glaucoma. We report a rare case of a 14-year-old male who presented with bilateral acute angle closure presumed to be related to his use of lisdexamfetamine dimesylate (Vyvanse). The patient's medication was discontinued which resulted in complete resolution of angle closure.

Pharmacologic treatment of attention deficit hyperactivity disorder in adults: A systematic review and network meta-analysis

Background

Attention deficit hyperactivity disorder (ADHD) affects approximately 3% of adults globally. Many pharmacologic treatments options exist, yet the comparative benefits and harms of individual treatments are largely unknown. We performed a systematic review and network meta-analysis to assess the relative effects of individual pharmacologic treatments for adults with ADHD.

Methods

We searched English-language published and grey literature sources for randomized clinical trials (RCTs) involving pharmacologic treatment of ADHD in adults (December 2018). The primary outcome was clinical response; secondary outcomes were quality of life, executive function, driving behaviour, withdrawals due to adverse events, treatment discontinuation, serious adverse events, hospitalization, cardiovascular adverse events, and emergency department visits. Data were pooled via pair-wise meta-analyses and Bayesian network meta-analyses. Risk of bias was assessed by use of Cochrane’s Risk of Bias tool, and the certainty of the evidence was assessed by use of the GRADE framework.

Results

Eighty-one unique trials that reported at least one outcome of interest were included, most of which were at high or unclear risk of at least one important source of bias. Notably, only 5 RCTs were deemed at overall low risk of bias. Included pharmacotherapies were methylphenidate, atomoxetine, dexamfetamine, lisdexamfetamine, guanfacine, bupropion, mixed amphetamine salts, and modafinil. As a class, ADHD pharmacotherapy improved patient- and clinician-reported clinical response compared with placebo (range: 4 to 15 RCTs per outcome); however, these findings were not conserved when the analyses were restricted to studies at low risk of bias, and the certainty of the finding is very low. There were few differences among individual medications, although atomoxetine was associated with improved patient-reported clinical response and quality of life compared with placebo. There was no significant difference in the risk of serious adverse events or treatment discontinuation between ADHD pharmacotherapies and placebo; however, the proportion of participants who withdrew due to adverse events was significantly higher among participants who received any ADHD pharmacotherapy. Few RCTs reported on the occurrence of adverse events over a long treatment duration.

Conclusions

Overall, despite a class effect of improving clinical response relative to placebo, there were few differences among the individual ADHD pharmacotherapies, and most studies were at risk of at least one important source of bias. Furthermore, the certainty of the evidence was very low to low for all outcomes, and there was limited reporting of long-term adverse events. As such, the choice between ADHD pharmacotherapies may depend on individual patient considerations, and future studies should assess the long-term effects of individual pharmacotherapies on patient-important outcomes, including quality of life, in robust blinded RCTs.

Registration

PROSPERO no. CRD 42015026049

[Risk of psychosis with treatment for ADHD]

The study by Moran et al. on the risk of psychosis among adolescents in the US who are treated with a stimulant for ADHD is important. This is because ADHD is a common disorder (3-5%), because psychosis often emerges in adolescence, because ADHD and psychosis share increased comorbidity and because ADHD is treated with stimulant medication that may increase the risk of psychosis. This means there is a multifactorial relationship between ADHD and psychosis.The outcome of the study is that stimulants increase the risk of psychosis to a limited extent, i.e. 0.10% for methylphenidate and 0.21% for dexamphetamine. It is recommended to opt for methylphenidate in adolescents with ADHD. This is confirmed by a Swedish registry study that controlled for a history of psychosis and showed that methylphenidate did not increase the incidence of psychosis after one year, regardless of a history of psychosis.

Repeated dexamphetamine treatment alters the dopaminergic system and increases the phMRI response to methylphenidate

Dexamphetamine (AMPH) is a psychostimulant drug that is used both recreationally and as medication for attention deficit hyperactivity disorder. Preclinical studies have demonstrated that repeated exposure to AMPH can induce damage to nerve terminals of dopamine (DA) neurons. We here assessed the underlying neurobiological changes in the DA system following repeated AMPH exposure and pre-treated rats with AMPH or saline (4 times 5 mg/kg s.c., 2 hours apart), followed by a 1-week washout period. We then used pharmacological MRI (phMRI) with a methylphenidate (MPH) challenge, as a sensitive and non-invasive in-vivo measure of DAergic function. We subsequently validated the DA-ergic changes post-mortem, using a.o. high-performance liquid chromatography (HPLC) and autoradiography. In the AMPH pre-treated group, we observed a significantly larger BOLD response to the MPH challenge, particularly in DA-ergic brain areas and their downstream projections. Subsequent autoradiography studies showed that AMPH pre-treatment significantly reduced DA transporter (DAT) density in the caudate-putamen (CPu) and nucleus accumbens, whereas HPLC analysis revealed increases in the DA metabolite homovanillic acid in the CPu. Our results suggest that AMPH pre-treatment alters DAergic responsivity, a change that can be detected with phMRI in rats. These phMRI changes likely reflect increased DA release together with reduced DAT binding. The ability to assess subtle synaptic changes using phMRI is promising for both preclinical studies of drug discovery, and for clinical studies where phMRI can be a useful tool to non-invasively investigate DA abnormalities, e.g. in neuropsychiatric disorders.

Sustained-release dexamfetamine in the treatment of chronic cocaine-dependent patients on heroin-assisted treatment: a randomised, double-blind, placebo-controlled trial

BACKGROUND

Heroin-assisted treatment is effective for methadone treatment-refractory heroin-dependent patients, but continued comorbid cocaine dependence remains problematic. Sustained-release dexamfetamine is a promising agonist pharmacotherapy for cocaine dependence and we aimed to assess its acceptance, efficacy, and safety.

METHODS

In this multicentre, randomised, double-blind, placebo-controlled trial, patients who were treatment-refractory, as indicated by at least two earlier failed treatments aimed at reducing or abstaining from cocaine use, and who regularly (≥8 days/month) used crack-cocaine were enrolled from four heroin-assisted treatment centres in the Netherlands. Eligible patients were randomly assigned (1:1) to receive either 12 weeks of daily, supervised prescription of 60 mg/day oral sustained-release dexamfetamine or placebo in addition to co-prescribed methadone and diacetylmorphine. Randomisation was done by the collaborating pharmacist, using a computer-generated random number sequence with stratification by treatment centre in blocks of four per stratum. Randomisation was masked to patients, staff, and researchers throughout the study. The primary outcome was the number of self-reported days of cocaine use during study treatment, assessed every 4 weeks. Primary and safety analyses were done in the intention-to-treat population. The study was registered with the European Union Drug Regulating Authorities Clinical Trials (EUdraCT 2013-004024-11) and with The Netherlands Trial Register (NTR2576).

FINDINGS

Between Aug 8, 2014, and Feb 27, 2015, 111 patients were assessed for eligibility, of whom 73 were enrolled and randomised; 38 patients were assigned to the sustained-release dexamfetamine group and 35 to the placebo group. Sustained-release dexamfetamine treatment resulted in significantly fewer days of cocaine use than placebo treatment (mean 44·9 days [SD 29·4] vs 60·6 days [24·3], respectively [95% CI of difference 3·1-28·4]; p=0·031; Cohen's standardised effect size d=0·58). One or more adverse events were reported by 28 (74%) patients in the dexamfetamine group and by 16 (46%) patients in the placebo group. Most adverse events were transient and well-tolerated.

INTERPRETATION

Sustained-release dexamfetamine is a well accepted, effective, and safe agonist pharmacotherapy for comorbid treatment-refractory cocaine dependence in heroin-dependent patients in heroin-assisted treatment. Future research should aim to replicate these findings in chronic cocaine-dependent and other stimulant-dependent patients in more routine treatment settings, including strategies to optimise treatment adherence like medication management interventions and contingency management.

FUNDING

Netherlands Organisation for Health Research and Development.

Generation Z: Adolescent Xenobiotic Abuse in the 21st Century

NMDA receptor antagonists include the prescription medication ketamine, the illicit xenobiotics PCP, MXE, and other novel PCP analogs, and the OTC medication DXM. The NMDA receptor antagonist most commonly abused by adolescents in the United States is DXM. These xenobiotics cause dissociative effects by non-competitively inhibiting the action of glutamate at the NMDA receptor. Additionally, these agents modulate the actions of monoamine neurotransmitters, agonize opioid receptors, and inhibit nitric oxide synthase. Patients typically present with sympathomimetic and neuropsychiatric clinical manifestations after abuse of NMDA receptor antagonists. Treatment is generally symptomatic and supportive. Interventions include benzodiazepines, propofol, fluids, antiemetics, aggressive cooling, and respiratory support.

Minimizing adverse events while maintaining clinical improvement in a pediatric attention-deficit/hyperactivity disorder crossover trial with dextroamphetamine and methylphenidate

OBJECTIVE

The purpose of this study was to investigate whether the availability of both dextroamphetamine and methylphenidate provides an opportunity to minimize adverse events in a pediatric attention-deficit/hyperactivity disorder (ADHD) stimulant trial.

METHODS

Thirty-six medication-naïve children 9-14 years of age, diagnosed with ADHD, were enrolled for 6 weeks in a crossover trial, with 2 weeks of methylphenidate, dextroamphetamine, and a placebo in a randomly assigned, counterbalanced sequence. Barkley's Side-Effect Rating Scale (SERS), rated by parents, was used to assess adverse events. SERS were available for 34 children, and data were analyzed both at the group and the single-subject level.

RESULTS

The side-effect profiles of dextroamphetamine and methylphenidate appeared similar at the group level. Overall, insomnia and decreased appetite were the only adverse events associated with the stimulants as compared with placebo. No significant increase from placebo to stimulant conditions was detected on SERS items reflecting emotional symptoms. Furthermore, dextroamphetamine and methylphenidate did not differ from each other on any SERS item, except that dextroamphetamine was associated with higher severity of "insomnia" and a higher prevalence of "unusually happy." Single-subject analyses showed that one or more adverse events were reported in 14 children (41%), and were evenly distributed between those with dextroamphetamine as the drug that showed the greatest reduction in their ADHD symptoms ("best drug") and those with methylphenidate as their best drug. Among children in whom both stimulants were associated with a decrease in ADHD symptoms, a clinically valid difference between the two stimulants in total adverse events score was found in 7 (39%) of the 18 cases. In these children, the availability of both stimulants provided an opportunity to minimize adverse events, while maintaining a reduction in ADHD symptoms.

CONCLUSIONS

The availability of both dextroamphetamine and methylphenidate may contribute to minimize adverse events in a subsample of children in pediatric ADHD stimulant trials.

CLINICAL TRIALS REGISTRY

The study was first registered in clinical trials September 28, 2010. Clinical Trials.gov Identifier: NCT01220440.

Efficacy of lisdexamfetamine dimesylate throughout the day in children and adolescents with attention-deficit/hyperactivity disorder: results from a randomized, controlled trial

Lisdexamfetamine dimesylate (LDX) is a long-acting, prodrug stimulant therapy for patients with attention-deficit/hyperactivity disorder (ADHD). This randomized placebo-controlled trial of an optimized daily dose of LDX (30, 50 or 70 mg) was conducted in children and adolescents (aged 6-17 years) with ADHD. To evaluate the efficacy of LDX throughout the day, symptoms and behaviors of ADHD were evaluated using an abbreviated version of the Conners' Parent Rating Scale-Revised (CPRS-R) at 1000, 1400 and 1800 hours following early morning dosing (0700 hours). Osmotic-release oral system methylphenidate (OROS-MPH) was included as a reference treatment, but the study was not designed to support a statistical comparison between LDX and OROS-MPH. The full analysis set comprised 317 patients (LDX, n = 104; placebo, n = 106; OROS-MPH, n = 107). At baseline, CPRS-R total scores were similar across treatment groups. At endpoint, differences (active treatment - placebo) in least squares (LS) mean change from baseline CPRS-R total scores were statistically significant (P < 0.001) throughout the day for LDX (effect sizes: 1000 hours, 1.42; 1400 hours, 1.41; 1800 hours, 1.30) and OROS-MPH (effect sizes: 1000 hours, 1.04; 1400 hours, 0.98; 1800 hours, 0.92). Differences in LS mean change from baseline to endpoint were statistically significant (P < 0.001) for both active treatments in all four subscales of the CPRS-R (ADHD index, oppositional, hyperactivity and cognitive). In conclusion, improvements relative to placebo in ADHD-related symptoms and behaviors in children and adolescents receiving a single morning dose of LDX or OROS-MPH were maintained throughout the day and were ongoing at the last measurement in the evening (1800 hours).

A systematic review of the safety of lisdexamfetamine dimesylate

BACKGROUND

Here we review the safety and tolerability profile of lisdexamfetamine dimesylate (LDX), the first long-acting prodrug stimulant for the treatment of attention-deficit/hyperactivity disorder (ADHD).

METHODS

A PubMed search was conducted for English-language articles published up to 16 September 2013 using the following search terms: (lisdexamfetamine OR lisdexamphetamine OR SPD489 OR Vyvanse OR Venvanse OR NRP104 NOT review [publication type]).

RESULTS

In short-term, parallel-group, placebo-controlled, phase III trials, treatment-emergent adverse events (TEAEs) in children, adolescents, and adults receiving LDX were typical for those reported for stimulants in general. Decreased appetite was reported by 25-39 % of patients and insomnia by 11-19 %. The most frequently reported TEAEs in long-term studies were similar to those reported in the short-term trials. Most TEAEs were mild or moderate in severity. Literature relating to four specific safety concerns associated with stimulant medications was evaluated in detail in patients receiving LDX. Gains in weight, height, and body mass index were smaller in children and adolescents receiving LDX than in placebo controls or untreated norms. Insomnia was a frequently reported TEAE in patients with ADHD of all ages receiving LDX, although the available data indicated no overall worsening of sleep quality in adults. Post-marketing survey data suggest that the rate of non-medical use of LDX was lower than that for short-acting stimulants and lower than or equivalent to long-acting stimulant formulations. Small mean increases were seen in blood pressure and pulse rate in patients receiving LDX.

CONCLUSIONS

The safety and tolerability profile of LDX in individuals with ADHD is similar to that of other stimulants.

Health-related quality of life and functional outcomes from a randomized-withdrawal study of long-term lisdexamfetamine dimesylate treatment in children and adolescents with attention-deficit/hyperactivity disorder

BACKGROUND

The stimulant prodrug lisdexamfetamine dimesylate (LDX) is an effective and generally well tolerated treatment for the symptoms of attention-deficit/hyperactivity disorder (ADHD). Positive impacts of LDX on health-related quality of life and functional impairment have previously been demonstrated in a 7-week, randomized, double-blind, placebo-controlled, phase III study in children and adolescents in Europe. Maintenance of these broad benefits, as well as symptomatic control, is a key goal of long-term management of ADHD.

OBJECTIVE

Secondary objectives of this multinational study in children and adolescents with ADHD were to assess the long-term maintenance of effectiveness of LDX in improving health-related quality of life and reducing functional impairment, as gauged using the Child Health and Illness Profile-Child Edition: Parent Report Form (CHIP-CE: PRF) and the Weiss Functional Impairment Rating Scale-Parent Report (WFIRS-P), respectively.

METHODS

Patients aged 6-17 years with diagnosed ADHD and a baseline ADHD Rating Scale IV total score of at least 28 were enrolled from the previous European study and from US sites. Patients who completed an open-label LDX treatment period of at least 26 weeks were randomized (1:1) to continue on their optimized dose of LDX or to switch to placebo for a 6-week, double-blind, withdrawal period. Parents completed CHIP-CE: PRF and WFIRS-P questionnaires at weeks 0, 8 and 26 of the open-label period and at weeks 0 and 6 of the randomized-withdrawal period, or at early termination. The endpoint of each period was defined as the last visit with valid data. Effect sizes were the difference (LDX minus placebo) in least-squares (LS)-mean change from baseline to endpoint divided by root-mean-square error. P values were nominal and not adjusted for multiple comparisons.

RESULTS

The open-label and randomized full analysis sets comprised 262 and 153 (LDX n = 76; placebo n = 77) patients, respectively. Mean pretreatment CHIP-CE: PRF T-scores were more than one standard deviation below the normative mean in four of the five domains, and there was significant improvement across all domains from baseline to endpoint of the open-label period. In the randomized-withdrawal period, LS-mean CHIP-CE: PRF T-scores deteriorated in all domains in the placebo group, but not in the LDX group. Compared with placebo, the effect of LDX was significant in the Risk Avoidance (effect size 0.829; p < 0.001), Achievement (0.696; p < 0.001) and Satisfaction (0.636; p < 0.001) domains. Mean pretreatment WFIRS-P scores were lowest in the Family domain and the Learning and School domain. WFIRS-P total score and scores in all domains improved significantly from baseline to endpoint of the open-label period. In the randomized-withdrawal period, LS-mean scores deteriorated in the placebo group but not in the LDX group. Compared with placebo, the effect of LDX was significant in the Family, Learning and School, and Risky Activities domains and in total (effect size 0.908; p < 0.001).

CONCLUSIONS

Using parent-rated instruments, long-term maintenance of the beneficial effect of LDX in multiple domains of health-related quality of life and functional impairment was demonstrated by comparison of treatment continuation and withdrawal under randomized, double-blind, placebo-controlled conditions.

Psychostimulants for managing unipolar and bipolar treatment-resistant melancholic depression: a medium-term evaluation of cost benefits

BACKGROUND

We earlier reported an open study of 50 unipolar and bipolar treatment resistant depressed patients indicating that psychostimulants may have differential superiority for the melancholic depressive sub-type. We designed an extension study to examine cost benefits of psychostimulants more closely for those only with melancholic depression.

METHOD

The sample comprised patients clinically diagnosed with melancholic depression who had failed to respond to and/or experienced significant side-effects with at least two antidepressants. Data were collected for 61 unipolar and 51 bipolar II patients receiving a psyschostimulant for a mean interval of 69 weeks. Benefits and side-effects were assessed.

RESULTS

Effectiveness ratings were similar across unipolar and bipolar sub-sets. Psychostimulants were judged as 'very' effective for 20% of patients and 'somewhat' effective for 50%. Forty percent judged the psychostimulant as being 'as effective' or as 'superior' to previously prescribed antidepressants, and worthy of being maintained. Significant side-effects were experienced by 40% of patients, requiring medication to be ceased in 12%. Twenty percent of the bipolar patients experienced a worsening of highs.

LIMITATIONS

The study was uncontrolled and retrospective, no formal rater-completed or patient-completed interval measures of severity were completed, while diagnostic judgments about melancholic depression and bipolar disorder were clinically judged.

CONCLUSIONS

This open study suggests that psychostimulants may be efficacious antidepressant options for managing unipolar and bipolar melancholia, often seemingly having very rapid onset and generally requiring only low doses, and arguing the need for controlled studies in melancholic patients.

Health-related quality of life and functional outcomes from a randomized, controlled study of lisdexamfetamine dimesylate in children and adolescents with attention deficit hyperactivity disorder

BACKGROUND

Optimal management of attention deficit hyperactivity disorder (ADHD) aims not only to ameliorate patients' symptoms, but also to improve health-related quality of life (HRQL) and functioning. A pivotal, 7-week, randomized, double-blind, placebo-controlled, phase III study in children and adolescents in ten European countries demonstrated that the stimulant prodrug lisdexamfetamine dimesylate (LDX) is an effective and generally well-tolerated treatment for symptoms of ADHD.

OBJECTIVE

The aim of this study was to assess HRQL and functional impairment outcomes in this clinical trial, using the Child Health and Illness Profile-Child Edition: Parent Report Form (CHIP-CE:PRF) and the Weiss Functional Impairment Rating Scale-Parent Report (WFIRS-P), respectively.

METHODS

Patients (aged 6-17 years) with diagnosed ADHD and a baseline ADHD Rating Scale IV total score ≥28 were randomized (1:1:1) to 7 weeks of double-blind treatment with once-daily LDX, placebo or the reference treatment, osmotic-release oral system methylphenidate (OROS-MPH). Participants' parents (or legally authorized representatives) completed the CHIP-CE:PRF and WFIRS-P questionnaires at baseline, at weeks 4 and 7, and/or at early termination. Endpoint was defined as the last on-treatment visit with valid data (≤30 % missing items). The CHIP-CE:PRF Achievement domain was pre-specified as the primary HRQL outcome.

RESULTS

The full analysis set comprised 317 patients (LDX, n = 104; placebo, n = 106; OROS-MPH, n = 107), the majority of whom completed the study (LDX, n = 77; placebo, n = 42; OROS-MPH, n = 72). Baseline CHIP-CE:PRF T-scores in four of the five domains were ≥1 standard deviation below norms (US community samples). Compared with placebo, LDX was associated with statistically significantly improved T-scores from baseline to endpoint in these four domains, with effect sizes of 1.280 (p < 0.001) in Achievement, 1.079 (p < 0.001) in Risk Avoidance, 0.421 (p < 0.01) in Resilience and 0.365 (p < 0.05) in Satisfaction. In LDX-treated patients, placebo-adjusted improvements from baseline to endpoint in WFIRS-P scores were statistically significant (p < 0.001) for total score and four of the six domains, with effect sizes of 0.924 (total score), 1.249 (Learning and School), 0.730 (Family), 0.643 (Social Activities) and 0.640 (Risky Activities). OROS-MPH treatment showed similar patterns of improvement from baseline to endpoint in both CHIP-CE:PRF and WFIRS-P scores.

CONCLUSIONS

Baseline HRQL and functional impairment scores reflect the burden of untreated ADHD. The benefits of short-term stimulant treatment in children and adolescents with ADHD extend beyond symptomatic relief and impact positively on HRQL and daily functioning.

Long-term treatment outcomes with lisdexamfetamine dimesylate for adults with attention-deficit/hyperactivity disorder stratified by baseline severity

OBJECTIVE

To examine the impact of baseline severity on lisdexamfetamine dimesylate (LDX) efficacy in a long-term study of adults with attention-deficit/hyperactivity disorder (ADHD).

RESEARCH DESIGN AND METHODS

Adults from a 4-week, placebo-controlled, forced dose-escalation study with LDX (30-70 mg/day) or placebo were enrolled in a long-term, open-label dose-optimization study for an additional 12 months. In post hoc analyses, participants were stratified by baseline severity (from the prior short-term study) with Clinical Global Impressions-Severity (CGI-S) scores of 4 (moderately), 5 (markedly), or ≥6 (severely/extremely ill). ADHD-Rating Scale IV (ADHD-RS-IV) with adult prompts (primary) and CGI-Improvement (CGI-I) were used to assess effectiveness. Clinical response was defined as a ≥30% decrease in ADHD-RS-IV from baseline and a CGI-I of 1 or 2; symptomatic remission was defined as ADHD-RS-IV ≤18. Treatment-emergent adverse events (TEAEs) were monitored.

RESULTS

Participants had baseline CGI-S scores of 4 (n = 114), 5 (n = 188), or ≥6 (n = 43). At endpoint, mean (SD) change from baseline in ADHD-RS-IV was greater (p < 0.0001) for participants with CGI-S = 5 (-26.4 [11.77]) and ≥6 (-32.3 [9.81]) than for participants with CGI-S = 4 (-19.5 [9.97]). At endpoint, 81.6%, 84.6%, and 88.4% of participants were very much/much improved (CGI-I of 1 or 2) in CGI-S categories of 4, 5, and ≥6, respectively. Clinical response criteria were met by 78.9%, 83.5%, and 88.4% and symptomatic remission criteria by 64.0%, 65.4%, and 72.1% of participants with CGI-S = 4, 5, and ≥6, respectively. The most frequently reported TEAEs with participant incidence ≥10% for any LDX dose were upper respiratory tract infection (21.8%), insomnia (19.5%), headache (17.2%), dry mouth (16.6%), decreased appetite (14.3%), and irritability (11.2%).

CONCLUSIONS

Some aspects of these analyses (e.g., open-label design without placebo control, inclusion and exclusion criteria of the demographic profile of participants, and the post hoc nature of the statistical analysis) limit interpretation. However, long-term LDX treatment demonstrated increased degree of symptom improvement with greater baseline symptom severity. Rates of clinical response and symptomatic remission tended to be greater for those with greater baseline severity. LDX demonstrated a safety profile consistent with long-acting stimulant use.

Clinical utility of ADHD symptom thresholds to assess normalization of executive function with lisdexamfetamine dimesylate treatment in adults

OBJECTIVES

This analysis assessed the relationship of various cutoff scores of the ADHD Rating Scale IV (ADHD-RS-IV) to levels of improvement in ADHD-related executive function (EF), measured by the Brown ADD Scale for Adults (BADDS), which may provide a measure of clinically meaningful EF improvement after ADHD treatment.

METHODS

Post hoc analysis of a 4-week, open-label, dose-optimization phase in a double-blind, placebo-controlled study of lisdexamfetamine dimesylate (LDX) in adults with ADHD. The BADDS for Adults, a validated, normed, self-report measure of EF in ADHD, provides a qualitative measure to rate treatment progress. The ADHD-RS-IV assesses current symptom status based on DSM-IV criteria. Postbaseline ADHD-RS-IV scores were categorized according to four cutoff criteria of symptom remission: (1) ADHD-RS-IV total score ≤ 18; (2) ADHD-RS-IV total score ≤ 10; (3) no ADHD-RS-IV item scored >1; and (4) ADHD-RS-IV total score ≤ 18 and ≤ 2 items per subscale with a score of 2. Sensitivity and specificity of criteria for identifying participants with optimal BADDS scores were assessed using receiver operating characteristics (ROC). Safety evaluation included treatment-emergent adverse events (TEAEs).

RESULTS

At endpoint, 85/127 participants had optimal BADDS scores. Linear ANOVA indicated limited overlap between BADDS and ADHD-RS-IV scores (r (2) = 0.20; P < 0.0001). Specificity was similar for criteria 1-4 (0.46, 0.39, 0.39, and 0.42), as were ROC (0.699, 0.776, 0.732, and 0.668). Sensitivity was high for criteria 2 and 3 (0.96, 0.92), lower for criteria 1 and 4 (0.72, 0.75). TEAEs were consistent with those of stimulants.

CONCLUSION

Criteria 2 and 3 had satisfactorily high sensitivity, but no criteria had adequate specificity. AUC comparison indicated that criteria 2 and 3 ADHD-RS-IV thresholds may be more accurate assessments of EF normalization as measured by the BADDS. The open-label design, small sample size, and selection criteria limit the applicability of these results to a larger treatment population.

Acute quetiapine dose-dependently exacerbates anhedonia induced by withdrawal from escalating doses of d-amphetamine

Recent clinical studies show that the atypical antipsychotic medication, quetiapine, may be beneficial in the treatment of substance abuse by alleviating the withdrawal-negative affect stage of addiction. Since the effect of quetiapine on central reward function is largely unknown we studied its effects on brain stimulation reward in animals under withdrawal from escalating doses of d-amphetamine. Male Sprague-Dawley rats were trained to produce an operant response to receive a short train of electrical stimulation to the lateral hypothalamus. Measures of reward threshold were determined with the curve-shift method in different groups of rats before, and during four days after treatment with escalating doses (1 to 10mg/kg, i.p.) of d-amphetamine or its vehicle. At 24h of withdrawal, the effects of two doses of quetiapine (2 and 10mg/kg i.p.) were tested. Animals treated with d-amphetamine showed a 25% reward deficit at 24h of withdrawal, an effect that decreased progressively over the next three days. Quetiapine attenuated reward in the vehicle-control animals, and amplified the anhedonia at the moderate, but not the low, dose in the animals under withdrawal. These results show that acute treatment with clinically relevant doses of quetiapine for the treatment of schizophrenia may exacerbate anhedonia induced by amphetamine withdrawal. Further research should investigate whether repeated treatment with quetiapine has the ability to reverse amphetamine withdrawal-induced anhedonia.

[Substitution of dexamethasone for dexamphetamine due to their written and spoken similarity]

We present a 15-year-old girl and an 11-year-old boy who were prescribed dexamphetamine for treatment of Attention Deficit Hyperactivity Disorder (ADHD), and who subsequently presented with symptoms indicative of Cushing's syndrome. It turned out that both children had taken high doses of dexamethasone instead of dexamphetamine due to an error made by the pharmacist. The diagnosis of exogenous Cushing's syndrome is easily made. However, it is a serious condition with possibly severe and persistent complications. The substitution of dexamethasone for dexamphetamine has been described before. Both doctors and pharmacists should be aware of this possible error.

Treatment for amphetamine withdrawal

BACKGROUND

Few studies examined treatments for amphetamine withdrawal, although it is a common problem among amphetamine users. Its symptoms, in particular intense craving, may be a critical factor leading to relapse to amphetamine use. In clinical practice, medications for cocaine withdrawal are commonly used to manage amphetamine withdrawal although the pharmacodynamic and pharmacokinetic properties of these two illicit substances are different.

OBJECTIVES

To assess the effectiveness of pharmacological alone or in combination with psychosocial treatment for amphetamine withdrawals on discontinuation rates, global state, withdrawal symptoms, craving, and other outcomes.

SEARCH STRATEGY

MEDLINE (1966 - 2008), CINAHL (1982 - 2008), PsycINFO (1806 - 2008), CENTRAL (Cochrane Library 2008 issue 2), references of obtained articles.

SELECTION CRITERIA

All randomised controlled and clinical trials evaluating pharmacological and or psychosocial treatments (alone or combined) for people with amphetamine withdrawal symptoms.

DATA COLLECTION AND ANALYSIS

Two authors evaluated and extracted data independently. The data were extracted from intention-to-treat analyses. The Relative Risk (RR) with the 95% confidence interval (95% CI) was used to assess dichotomous outcomes. The Weighted Mean Difference (WMD) with 95% CI was used to assess continuous outcomes.

MAIN RESULTS

Four randomised controlled trials (involving 125 participants) met the inclusion criteria for the review. Two studies found that amineptine significantly reduced discontinuation rates and improved overall clinical presentation, but did not reduce withdrawal symptoms or craving compared to placebo. The benefits of mirtazapine over placebo for reducing amphetamine withdrawal symptoms were not as clear. One study suggested that mirtazapine may reduce hyperarousal and anxiety symptoms associated with amphetamine withdrawal. A more recent study failed to find any benefit of mirtazapine over placebo on retention or on amphetamine withdrawal symptoms.

AUTHORS' CONCLUSIONS

No medication is effective for treatment of amphetamine withdrawal. Amineptine showed reduction in discontinuation rates and improvement in clinical presentation compared to placebo, but had no effect on reducing withdrawal symptoms or craving. In spite of these limited benefits, amineptine is not available for use due to concerns over abuse liability when using the drug. The benefits of mirtazapine as a withdrawal agent are less clear based on findings from two randomised controlled trials: one report showed improvements in amphetamine withdrawal symptoms over placebo; a second report showed no differences in withdrawal symptoms compared to placebo. Further potential treatment studies should examine medications that increase central nervous system activity involving dopamine, norepinephrine and/or serotonin neurotransmitters, including mirtazapine.

A randomized, double-blind, placebo-controlled trial assessing the impact of dexamphetamine on fatigue in patients with advanced cancer

Fatigue is very common in patients with cancer. Current guidelines suggest that psychostimulants are "reasonable to consider for severe fatigue." This randomized, double-blind, placebo-controlled trial investigated the hypothesis that dexamphetamine in fatigued patients with advanced cancer would produce a clinically significant improvement with minimal side effects. Fifty patients with advanced cancer, who were receiving palliative care, were randomized to dexamphetamine 10mg twice daily or placebo for eight days. Effectiveness was assessed using the Brief Fatigue Inventory and the McGill Quality-of-Life Questionnaire. The side effects were recorded. The results were analyzed on an intention-to-treat basis. The baseline demographics, fatigue levels, and quality-of-life scores were similar between the two arms. Patients were elderly, had impaired performance status (Eastern Cooperative Oncology Group score=3), and were taking a range of neurologically active medications. Thirty-nine patients completed the trial. There was a transient improvement in the fatigue levels on day 2, but no significant difference in fatigue (P=0.267) or quality of life (P=0.579) by the end of the study. Statistical modeling did not reveal any significant predictors of response to dexamphetamine. These results suggest that dexamphetamine 20mg daily, although well tolerated, does not significantly improve fatigue or quality of life in patients with advanced cancer, as measured by the selected instruments.

Pharmacologic treatment of ADHD: road conditions in driving patients to successful outcomes

The names assigned to attention-deficit/hyperactive disorder (ADHD) have changed over the years. ADHD cannot be cured, and the patient with ADHD journeys through life with a burden. Although ADHD is most commonly studied in school-aged children, it is a syndrome that spans the life cycle, through adolescence and into adulthood. Improvements in patient adherence to pharmacologic treatment, attributable to the launch of new formulations, the availability of new non-schedule II drugs, and the development of novel drugs in late-stage clinical trials, are transforming the treatment of ADHD. For example, atomoxetine is a nonstimulant treatment, and lisdexamfetamine was developed with the goal of providing an extended duration of effect with a reduced potential for abuse, overdose toxicity, and drug tampering. Known adverse effects of stimulant treatment of ADHD include appetite suppression and sleep disturbance. Other adverse effects, such as growth suppression and substance use disorder, are controversial. The US Food and Drug Administration (FDA) recently issued a public health advisory for drugs approved for the treatment of ADHD to provide more information for patients about potential risks of ADHD medications. Additional research is needed on approaches for treating ADHD in adolescents transitioning into adulthood, as are studies on the relationships between ADHD and comorbidities such as substance use disorder.

Multiple daily-dose pharmacokinetics of lisdexamfetamine dimesylate in healthy adult volunteers

OBJECTIVE

To evaluate the pharmacokinetics of lisdexamfetamine dimesylate (LDX; Vyvanse) in fasting healthy adult volunteers.

BACKGROUND

LDX is the first pro-drug stimulant and is indicated for the treatment of attention-deficit/hyperactivity disorder. LDX was developed with the goal of providing an extended effect that is consistent throughout the day, with a reduced potential for abuse, overdose toxicity, and drug tampering.

METHODS

This was an open-label, multipledose phase 1 study. LDX 70 mg/d was administered in the morning to 12 subjects for 7 days. Twenty blood samples were drawn during the study. Descriptive statistics were used for pharmacokinetic parameters.

RESULTS

Based on C(min), steady-state d-amphetamine concentration (20.6 ng/mL) was reached by day 5, whereas LDX was undetectable, and 95% of the d-amphetamine was eliminated within 48 hours following the final dose on day 7. At steady state, d-amphetamine achieved a mean +/- standard deviation C(max) of 90.1 +/- 29.6 ng/mL, with a median T(max) of 3.0 hours. The AUC(0-inf) for d-amphetamine was 1453 +/- 645.7 ng.h/mL. Complete elimination of the pro-drug occurred approximately 6 hours following the final dose on day 7. Adverse events were mild to moderate and similar to other oral amphetamines.

CONCLUSIONS

This study describes the steady-state pharmacokinetics of LDX, a new pro-drug stimulant. Possible study limitations include an open-label design and a small sample size.

Behavioral effects of subchronic inorganic manganese exposure in rats

BACKGROUND

Manganese, an essential micronutrient, is a potential neurotoxicant in prolonged overexposure. Parkinson-like syndrome, motor deficit, disturbed psychomotor development are typical signs of neuropathological alterations due to Mn in humans.

METHODS

Young adult rats, in three groups of 16 each, received 15 and 59 mg/kg b.w. MnCl(2), (control: distilled water) via gavage for 10 weeks, and were kept for further 12 weeks. Correlation of MnCl(2) exposure to body and organ weights, neurobehavioral effects (spatial memory, exploratory activity, psychomotor performance, pre-pulse inhibition), and histopathological changes (gliosis) was sought.

RESULTS

By the end of treatment, Mn accumulated in blood, cortex, hippocampus, and parenchymal tissues. Body and organ weights were reduced in high dose rats. All treated rats showed hypoactivity, decreased memory performance, and diminished sensorimotor reaction. In the dentate gyrus of these, GFAP immunoreactivity increased. During the post-treatment period, body weight of the high dose group remained decreased, locomotor activity returned to control, but the lasting effect of MnCl(2) could be revealed by amphetamine.

CONCLUSION

Using complex methodology, new data were obtained regarding the relationship between the long-term effects of MnCl(2) at neuronal and behavioral level.

Interference with Smoking-Cessation Effects of Varenicline After Administration of Immediate-Release Amphetamine-Dextroamphetamine

An 18-year-old man with attention-deficit-hyperactivity disorder (ADHD) was prescribed varenicline for smoking cessation. He quit smoking after 1 week of therapy and remained smoke free for the next 17 days. During that time, he had also been taking amphetamine-dextroamphetamine (Adderall) on work days for his ADHD. Because his supply of amphetamine-dextroamphetamine was diminishing, he took only half (30 mg every morning) of his prescribed dosage from days 4-12 of varenicline therapy. He further reduced his dosage to 15 mg every morning on days 13 and 14 of varenicline therapy, and his supply of amphetamine-dextroamphetamine was depleted on day 15. On day 23 of varenicline therapy, he received and filled a new prescription for amphetamine-dextroamphetamine and resumed his prescribed dosage (30 mg twice/day). He began smoking again within 48 hours. Rechallenge with varenicline while the patient continued to receive amphetamine-dextroamphetamine yielded similar results. Data suggest that addition of amphetamine to varenicline may negate the partial agonism of varenicline, resulting in elimination of the smoking-cessation aid's benefits. Other potential mechanisms for the drug interaction may also exist. Thus, varenicline may not aid smoking cessation in patients undergoing treatment with amphetamine and amphetamine-like drugs.

Quantification of Phosphorylated cAMP-Response Element-Binding Protein Expression throughout the Brain of Amphetamine-Sensitized Rats: Activation of Hypothalamic Orexin A-Containing Neurons

In the present study, using rats, we have examined acute, contextual, and sensitized patterns of activated or phosphorylated cAMP response element-binding protein (pCREB) expression in parallel, assaying across multiple nuclei that have been implicated in addiction. The paradigm used included a comparison of pretreatment dose of amphetamine upon patterns of cellular activation, following rechallenge. Because efferent orexinergic projections synapse on many targets through the mammalian brain, including mesotelencephalic regions and limbic systems involved in drug reward and reinforcement, we examined for coexpression of pCREB or c-Fos double labeling within orexin A-immunopositive neurons following sensitization. Acute challenge with amphetamine (1.5 mg/kg i.p.) resulted in an increase in the number of pCREB-immunoreactive (-IR) cells within the substantia nigra but a decrease of pCREB-IR cells in the central and medial subnuclei of the amygdala. Contextual re-exposure to the drug treatment environment altered pCREB expression, particularly in the basal ganglia and hypothalamus, although these effects were dictated by pretreatment dose of amphetamine. Sensitization to amphetamine resulted in robust increases in pCREB-IR cell numbers in the basal ganglia and lateral septum of rats that had been pretreated with high-dose (10 mg/kg i.p.) but not low-dose (2 mg/kg i.p.) amphetamine, despite a similar behavioral response. Orexin A-containing cells in the hypothalamus of sensitized rats did not coexpress pCREB; however, these cells double-labeled for c-Fos and orexin A. These data suggest that orexinergic neurons are activated during the expression of behavioral sensitization, although in a heterogenous manner with regard to afferent topologies and functional roles in the nervous system.

Lisdexamfetamine

Lisdexamfetamine is an amphetamine prodrug, comprising an l-lysine amino acid covalently bonded to dextroamphetamine (d-amphetamine). Lisdexamfetamine is approved in the US for the treatment of attention-deficit hyperactivity disorder in children aged 6-12 years. Lisdexamfetamine is a therapeutically inactive molecule. After oral ingestion, lisdexamfetamine is hydrolyzed to l-lysine, a naturally occurring essential amino acid, and active d-amphetamine, which is responsible for the activity of the drug. In a well designed pharmacodynamic study in adult stimulant abusers, 50 or 100 mg doses of oral lisdexamfetamine had less likability than d-amphetamine 40 mg, suggesting a reduced abuse potential. Through rate-limited hydrolysis in the body, l-lysine is cleaved, gradually releasing pharmacologically active d-amphetamine. The pharmacokinetics of lisdexamfetamine suggest a reduced potential for abuse. In two well designed trials in children aged 6-12 years with attention-deficit hyperactivity disorder (ADHD), the efficacy of lisdexamfetamine was superior to that of placebo in improving symptoms associated with ADHD. Adverse events with lisdexamfetamine were, in general, mild to moderate in severity and consistent with those commonly reported with amphetamine.

The reinforcing, subject-rated, performance, and cardiovascular effects of d-amphetamine: influence of sensation-seeking status

Individual differences that may contribute to vulnerability to abuse drugs have been identified. Sensation-seeking status has been shown to influence both vulnerability to drug use and response to acute drug administration. The purpose of the present experiment was to examine the reinforcing effects of d-amphetamine in high and low sensation-seeking subjects using a modified progressive-ratio procedure. A battery of subject-rated, performance, and cardiovascular measures was also included to better characterize the effects of d-amphetamine in these groups. Ten high sensation seekers and ten low sensation seekers that were matched for education, age, drug use, height, and weight, first sampled doses of d-amphetamine (0, 8, and 16 mg). In subsequent sessions, subjects were offered the opportunity to work for the sampled dose on a modified progressive-ratio procedure. d-Amphetamine functioned as a reinforcer and produced prototypical stimulant-like effects (e.g., increased subject-ratings of Like Drug, enhanced performance, and increased heart rate). High sensation seekers were more sensitive than low sensation seekers to the reinforcing and some of the subject-rated effects of d-amphetamine. The results of the present experiment extend those of previous findings by demonstrating that the reinforcing effects of d-amphetamine vary as a function of the biologically based sensation-seeking personality trait. These results suggest that increased stimulant drug use and abuse among high sensation seekers may be related, in part, to increased sensitivity to the reinforcing effects of stimulants among these individuals.

A triazolam/amphetamine dose-effect interaction study: dissociation of effects on memory versus arousal

RATIONALE

In addition to producing robust memory impairment, benzodiazepines also induce marked sedation. Thus, it is possible that the observed amnestic effects are secondary to more global sedative effects and do not reflect a specific primary benzodiazepine effect on memory mechanisms.

OBJECTIVE

The objective was to use the nonspecific stimulant d-amphetamine to dissociate the sedative and memory-impairing effects of the benzodiazepine triazolam.

MATERIALS AND METHODS

Single oral doses of placebo, triazolam alone (0.25, 0.50 mg/70 kg), d-amphetamine sulfate alone (20, 30 mg/70 kg), and triazolam (0.25, 0.50 mg/70 kg) and d-amphetamine sulfate (20, 30 mg/70 kg) conjointly (at all dose combinations) were administered to 18 healthy adult participants across nine sessions in a double-blind, staggered-dosing, crossover design. In addition to standard data analyses, analyses were also conducted on z-score standardized data, enabling effects to be directly compared across measures.

RESULTS

Relative to the sedative measures, the memory measures generally exhibited a pattern of less reversal of triazolam's effects by d-amphetamine. The memory measures ranged in degree of reversal such that the most reversal was observed for reaction time on the n-back working memory task, and the least reversal was observed for accuracy on the Sternberg working memory task, with most measures showing an overall pattern of partial reversal.

CONCLUSIONS

Benzodiazepines have specific effects on memory that are not merely a by-product of the drugs' sedative effects, and the degree to which sedative effects contribute to the amnestic effects varies as a function of the particular memory process being assessed.

Enduring deficits in sustained visual attention during withdrawal of intravenous methylenedioxymethamphetamine self-administration in rats: results from a comparative study with d-amphetamine and methamphetamine

Although amphetamine-derived stimulants are widely associated with neurotoxicity, it is poorly understood whether extended exposure to such drugs produces lasting effects on neurocognitive function. This study investigates whether chronically self-administered d-amphetamine, methamphetamine (MA), or methylenedioxymethamphetamine (MDMA) leads to residual deficits in a rodent test of sustained visual attention and impulsivity. Rats were trained on a five-choice serial reaction time task and subsequently trained to self-administer d-amphetamine, MA, or MDMA (all 50 microg/infusion), intravenously, for 3 weeks. Effects on performance were evaluated 24 h after drug discontinuation and for several weeks thereafter, including various challenge sessions to increase the attentional demands of the task. The results indicate divergent patterns of self-administration among the three drugs tested with increasing rates of intake evident in rats self-administering amphetamine, but not MA, and widely fluctuating rates in the MDMA group. Withdrawal of MA resulted in severe behavioral disturbances, with significant effects on accuracy, omissions, response latency, and impulsivity that lasted up to 2 weeks in some cases. Amphetamine and MDMA withdrawal were associated with similar, but shorter-lasting effects on performance. However, when challenged with a high event rate session 6 weeks after drug discontinuation, rats previously exposed to MDMA continued to show deficits in the accuracy and speed of responding. These findings show that amphetamine-derived stimulants have both short- and long-term consequences for psychomotor functioning. The demonstration of residual deficits in rats chronically exposed to MDMA raises some concern about the potential harm caused by this drug in human ecstasy users.

Psychostimulants and Military Operations

Sleep-deprived individuals appear to have decreased psychological and physical capabilities. Studies have shown how major psychological aspects, such as alertness, complex mental performance, and memory, are strongly affected by sleep deprivation. Military use of psychostimulants dates back many years, especially in units that operate over long hours and deprive soldiers of sleep. During prolonged military operations, pilots are regularly kept awake for hours and days without fulfilling their biological sleep requirements. This consequently affects their natural circadian rhythm. This article deals with both the benefits and the side effects of two kinds of psychostimulants, namely, dextroamphetamine, which is more popular and is most widely used, and modafinil, which is a relatively newer type. There is growing evidence that modafinil has fewer side effects, in comparison with its predecessor dextroamphetamine, while still maintaining all of the latter's beneficial characteristics.

Efficacy and tolerability of lisdexamfetamine dimesylate (NRP-104) in children with attention-deficit/hyperactivity disorder: A Phase III, multicenter, randomized, double-blind, forced-dose, parallel-group study

BACKGROUND

Lisdexamfetamme dimesylate (LDX) is a therapeutically inactive amphetamine prodrug. It was developed with the goal of providing an extended duration of effect that is consistent throughout the day, with a reduced potential for abuse, overdose toxicity, and drug tampering. Following ingestion, the pharmacologically active d-amphetamine molecule is gradually released by rate-limited hydrolysis.

OBJECTIVES

The aims of this study were to assess the efficacy and tolerability of LDX in school-aged children with attention-deficit/hyperactivity disorder (ADHD) treated in the community, and to characterize the duration of action of LDX compared with placebo.

METHODS

This Phase III, multicenter, randomized, double-blind, forced-dose, parallel-group study was conducted at 40 centers across the United States. Male and female children aged 6 to 12 years with ADHD were randomly assigned to receive LDX 30, 50, or 70 mg with forced-dose titration, or placebo, PO QD for 4 weeks. Efficacy was assessed using the ADHD Rating Scale Version IV (ADHD-RS-IV), the Conners' Parent Rating Scale (CPR'), and the Clinical Global Impression of Improvement scale. Tolerability was assessed throughout the study.

RESULTS

Of the 290 randomized patients (201 boys, 89 girls; mean [SD] age, 9 [1.8] years), 230 completed the trial (LDX 30 mg, n=56; LDX 50 mg, n=60; LDX 70 mg, n=60; and placebo, n=54). The most common reasons for study discontinuation (n=60) were lack of efficacy (LDX 30 mg, 1%; LDX 50 mg, 0%; LDX 70 mg, 1 %; and placebo, 17%) and adverse events (AEs) (LDX 30 mg, 9%; LDX 50 mg, 5%; LDX 70 mg, 14%; and placebo, 1%). Significant improvements in ADHD-RS-IV scores were seen with all doses of LDX compared with placebo (all, P<0.001), and in CPRS scores with all LDX doses versus placebo throughout the day (all, P<0.001 for all comparisons). Efficacy was observed by the first week of treatment, and improvements were observed throughout the day up to approximately 6 PM. The most frequently reported AEs among patients receiving LDX were typical of amphetamine products: decreased appetite (39% with active treatment vs 4% with placebo), insomnia (19% vs 3%), upper abdominal pain (12% vs 6%), headache (12% vs 10%), irritability (10% vs 0%), vomiting (9% vs 4%), weight decrease (9% vs 1%), and nausea (6% vs 3%); most were mild to moderate and occurred in the first week.

CONCLUSION

In this population of children with ADHD, treatment once daily with the prodrug LDX at doses of 30 to 70 mg appeared to be effective and had a tolerability profile similar to those of currently marketed extended-release stimulants.

Transfer of dexamphetamine into breast milk during treatment for attention deficit hyperactivity disorder

AIMS

To investigate dexamphetamine transfer into milk, infant doses and effects in the breast-fed infant.

METHODS

Four women taking dexamphetamine, and their infants were studied.

RESULTS

The median maternal dexamphetamine dose was 18 mg day(-1) (range 15-45 mg day(-1)). Median (interquartile range) descriptors were 3.3 (2.2-4.8) for milk/plasma ratio, 21 microg kg(-1) day(-1) (11-39) for absolute infant dose and 5.7% (4-10.6%) for relative infant dose. No adverse effects were seen. In three infants tested, dexamphetamine in plasma was undetected in one (limit of detection 1 microg l(-1)) and present at 18 microg l(-1) and 2 microg l(-1) in the other two.

CONCLUSION

Dexamphetamine readily transfers into milk. The relative infant dose was <10% and within a range that is generally accepted as being 'safe' in the short term.

Differential effects on prepulse inhibition of withdrawal from two different repeated administration schedules of amphetamine

In this study, rats were tested in behavioural paradigms relevant to schizophrenia during withdrawal from two different administration schedules of amphetamine (Amph). One of the escalating administration schedules, which has been employed in previous studies, consisted of three daily injections for 6 d with increasing dosages from 1 to 5 mg/kg Amph (Esc-5) and was compared to a hitherto never examined escalating administration schedule [three injections per day for 6 d escalating from 1 to 8 mg/kg Amph (Esc-8)]. Control animals received an equivalent volume of saline (Sal) injections according to the same schedule. Whereas rats treated with Esc-5, as reported before, failed to show an effect on prepulse inhibition (PPI), the Esc-8-treated rats exhibited a long-lasting disruption of PPI in a drug-free state on days 6, 13 and 55 of withdrawal. The Amph-pretreated animals demonstrated a similar magnitude of behavioural sensitization following an Amph challenge on withdrawal day 58 irrespective of the administration schedule. To evaluate if the withdrawal from the two Amph schedules led to a change in brain monoamine levels, a subgroup of animals was neurochemically examined in post-mortem for eight parameters in seven brain regions on withdrawal day 55. Withdrawal from the Esc-8 schedule induced reduced dopamine levels in the caudate putamen. Only this neurochemical finding and the PPI attenuation differentiated the Esc-8 animals from the Esc-5 and Sal animals. These data suggest that, based on the endogenous sensitization hypothesis of schizophrenia, the persistent disruption of PPI observed in animals withdrawn from Esc-8 can be used as a valid animal model of specific symptoms of schizophrenic patients.

Increased oxidative stress after repeated amphetamine exposure: possible relevance as a model of mania

BACKGROUND

Acute mania can be modeled in animals using D-amphetamine (AMPH). Acute AMPH injections are associated with monoamine depletion, loss of neurofilaments and neurite degeneration. However, the precise mechanisms underlying AMPH-induced neurotoxicity are still unclear. Several studies have demonstrated that oxidative stress may play a role in the behavioral and neurochemical changes observed after AMPH administration.

METHODS

The effects of a single and repeated injections (seven daily injections) of AMPH administered intraperitonially on locomotion and the production of lipid and protein oxidative markers in rat cortex, striatum and hippocampus were assessed. Locomotion was assessed in an open-field task and markers of oxidative stress were assessed in brain tissue.

RESULTS

Both single and repeated injections of AMPH increased protein carbonyl formation in rat brain. Repeated exposure to AMPH induced an additional increase in thiobarbituric acid reactive species in brain tissue.

CONCLUSIONS

Longer periods of exposure to AMPH were associated with increased oxidative stress in rat brain. This adds to the notion that repeated manic episodes may be associated with greater brain damage and, therefore, poorer outcomes.

A randomized double-blind trial of paroxetine and/or dextroamphetamine and problem-focused therapy for attention-deficit/hyperactivity disorder in adults

OBJECTIVE

To determine the effect of psychotherapy, dextroamphetamine, and/or paroxetine on attention-deficit/hyperactivity-disorder (ADHD) in adults.

METHOD

Ninety-eight adults with DSM-IV ADHD were randomly assigned to receive psychotherapy and dextroamphetamine, paroxetine, both, or placebo for 20 weeks. A 2 x 2 factorial design compared patients who received dextroamphetamine versus no dextroamphetamine with patients who received paroxetine versus no paroxetine. Data were collected from August 2000 until May 2002.

RESULTS

One half of the 98 enrolled subjects were found to have at least 1 lifetime mood or anxiety disorder on the Structured Clinical Interview for DSM-IV. Sixty percent of patients who received medication and 80% of those who received placebo completed the 5-month trial. ADHD symptoms were significantly (p = .012) lower in patients in the completer group who received dextroamphetamine. Paroxetine had no effect on ADHD. Hamilton Rating Scales for Anxiety (HAM-A) and Depression (HAM-D) scores were low to start, and no treatment differences were evident at endpoint. Significantly (p < .001) more patients in the completer group were rated by clinicians as ADHD responders if they received dextroamphetamine (85.7%) or combined treatment (66.7%) versus paroxetine (20.0%) or placebo (21.1%). Significantly (p = .003) more patients in the completer group were rated by clinicians as mood/anxiety responders if they received paroxetine (100%) or combined treatment (73.3%) versus those receiving dextroamphetamine (57.15%) or placebo (47.4%). Clinicians rated any patient who received medication and psychological therapy as significantly more improved overall than those who received placebo and psychological therapy (intent to treat: p = .033; completers: p = .001).

CONCLUSION

ADHD symptoms improved with dextroamphetamine. Mood and internalizing symptoms were seen as improved with paroxetine by clinicians, despite absence of response on the HAM-A and HAM-D. The presence of a lifetime internalizing disorder attenuated the response to dextroamphetamine. Patients who received both dextroamphetamine and paroxetine had more severe adverse events but did not show greater improvement overall than patients treated with 1 medication. Clinical Trials Registry #GSK707.

Genetic identification of AChE as a positive modulator of addiction to the psychostimulant D-amphetamine in zebrafish

Addiction is a complex maladaptive behavior involving alterations in several neurotransmitter networks. In mammals, psychostimulants trigger elevated extracellular levels of dopamine, which can be modulated by central cholinergic transmission. Which elements of the cholinergic system might be targeted for drug addiction therapies remains unknown. The rewarding properties of drugs of abuse are central for the development of addictive behavior and are most commonly measured by means of the conditioned place preference (CPP) paradigm. We demonstrate here that adult zebrafish show robust CPP induced by the psychostimulant D-amphetamine. We further show that this behavior is dramatically reduced upon genetic impairment of acetylcholinesterase (AChE) function in ache/+ mutants, without involvement of concomitant defects in exploratory activity, learning, and visual performance. Our observations demonstrate that the cholinergic system modulates drug-induced reward in zebrafish, and identify genetically AChE as a promising target for systemic therapies against addiction to psychostimulants. More generally, they validate the zebrafish model to study the effect of developmental mutations on the molecular neurobiology of addiction in vertebrates.

Long-term stimulant medication treatment of attention-deficit/hyperactivity disorder: results from a population-based study

The purpose of this study was to offer detailed information about stimulant medication treatment provided throughout childhood to 379 children with research-identified attention-deficit hyperactivity disorder (ADHD) in the 1976-1982 Rochester, MN, birth cohort. Subjects were retrospectively followed from birth until a mean of 17.2 years of age. The complete medical record of each subject was reviewed. The history and results of each episode of stimulant treatment were compared by gender, DSM-IV subtype of ADHD, and type of stimulant medication. Overall, 77.8% of subjects were treated with stimulants. Boys were 1.8 times more likely than girls to be treated. The median age at initiation (9.8 years), median duration of treatment (33.8 months), and likelihood of developing at least one side effect (22.3%) were not significantly different by gender. Overall, 73.1% of episodes of stimulant treatment were associated with a favorable response. The likelihood of a favorable response was comparable for boys and girls. Treatment was initiated earlier for children with either ADHD combined type or ADHD hyperactive-impulsive type than for children with ADHD predominantly inattentive type and duration of treatment was longer for ADHD combined type. There was no association between DSM-IV subtype and likelihood of a favorable response or of side effects. Dextroamphetamine and methylphenidate were equally likely to be associated with a favorable response, but dextroamphetamine was more likely to be associated with side effects. These results demonstrate that the effectiveness of stimulant medication treatment of ADHD provided throughout childhood is comparable to the efficacy of stimulant treatment demonstrated in clinical trials.

Effect of stimulants on 24-h ambulatory blood pressure in children with ADHD: a double-blind, randomized, cross-over trial

Millions of children with attention deficit hyperactivity disorder (ADHD) are treated with stimulant medications. To evaluate cardiovascular risk, 24-h ambulatory blood pressure monitoring (ABPM) was performed on and off medication. Thirteen subjects underwent APBM both on stimulant therapy and placebo using a placebo-controlled, double-blind, randomized, cross-over design. After a 3-day run-in followed by a 24-h monitoring period, subjects crossed over to the alternate therapy for repeated ABPM. Subjects demonstrated elevations in most hemodynamic parameters derived from ABPM during the active treatment period. Total diastolic blood pressure (69.7 mmHg vs 65.8 mmHg, p =0.02) and waking diastolic blood pressure (75.5 mmHg vs 72.3 mmHg, p =0.03) were significantly higher during active treatment. Total heart rate was also significantly higher during active treatment (85.5 beats/min vs 79.9 beats/min, p =0.004). The rate-pressure product (the product of systolic blood pressure x heart rate), an index of myocardial oxygen demand, was higher during active treatment (9,958 vs 9,076, p =0.008). This study provides evidence for a possible negative cardiovascular effect of stimulant medications in children with ADHD. This potential cardiovascular risk should be balanced against the beneficial behavioral effects of this class of medication.

Withdrawal from repeated amphetamine administration leads to disruption of prepulse inhibition but not to disruption of latent inhibition

The present study represents a continuous effort to develop an animal model of schizophrenia based on the "endogenous dopamine sensitization" hypothesis. To achieve this goal, withdrawal from an escalating amphetamine (AMPH) regime administration [three injections per day over a period of 4 days and increasing doses from 1 to 10 mg/kg of AMPH or an equivalent volume of saline (SAL)] was employed. Animals exposed to this treatment were evaluated on their performance in attentional (Latent inhibition, LI) and sensorimotor gating (Prepulse inhibition, PPI) tasks in a drug free state and tested for locomotor sensitization following a low dose of AMPH challenge administration.LI using active avoidance, tested on withdrawal day 4, was unaffected. PPI of the acoustic startle response, measured on withdrawal days 6 and 70, was disrupted. On the 76th day of withdrawal, a low challenge dose of AMPH (1 mg/kg) led to a clear locomotor sensitization effect.

NTP-CERHR monograph on the potential human reproductive and developmental effects of amphetamines

The National Toxicology Program (NTP) Center for the Evaluation of Risks to Human Reproduction (CERHR) conducted an evaluation of the potential for amphetamines to cause adverse effects on reproduction and development in humans. Amphetamines evaluated were D- and D,L-amphetamine and methamphetamine. Amphetamine is approved by the U.S. Food and Drug Administration for the treatment of attention deficit hyperactivity disorder (ADHD) in persons over 3 years of age and narcolepsy; methamphetamine is approved for the treatment of ADHD in persons 6 years of age and older and for short-term treatment of obesity. Amphetamines were selected for evaluation because of 1) widespread usage in children, 2) availability of developmental studies in children and experimental animals, and 3) public concern about the effect of this stimulant on child development. The results of this evaluation on amphetamines are published in an NTP-CERHR monograph which includes: 1) the NTP Brief, 2) the Expert Panel Report on the Reproductive and Developmental Toxicity of Methylphenidate, and 3) public comments received on the Expert Panel Report. As stated in the NTP Brief, the NTP reached the following conclusions regarding the possible effects of exposure to methylphenidate on human development and reproduction. First, there is some concern for developmental effects, specifically for potential neurobehavioral alterations, from prenatal amphetamine exposure in humans both in therapeutic and non-therapeutic settings. After prenatal exposure to therapeutic doses of amphetamine, rat pups demonstrated neurobehavioral alterations. Data from human and animal studies were judged insufficient for an evaluation of the effect of amphetamine exposure on growth and other related developmental effects. Second, there is concern for methamphetamine-induced adverse developmental effects, specifically on growth and neurobehavioral development, in therapeutic and non-therapeutic settings. This conclusion is based on evidence from studies in experimental animals that prenatal and postnatal exposures to methamphetamine produce neurobehavioral alterations, small litter size, and low birth weight. Results from studies in humans suggest that methamphetamine may cause low birth weight and shortened gestation, but study confounders such as possible multiple drug usage prevent a definite conclusion. NTP-CERHR monographs are transmitted to federal and state agencies, interested parties, and the public and are available in electronic PDF format on the CERHR web site (http://cerhr.niehs.nih.gov) and in printed text or CD-ROM from the CERHR (National Institute of Environmental Health Sciences, P.O. Box 12233, MD EC-32, Research Triangle Park, NC; fax: 919-316-4511).

The partial D2-like dopamine receptor agonist terguride acts as a functional antagonist in states of high and low dopaminergic tone: evidence from preweanling rats

RATIONALE

In adult rats, the partial D(2)-like agonist terguride acts as an antagonist at normosensitive D(2)-like post-synaptic receptors, while it acts as an agonist at the same receptors during states of low dopaminergic tone.

OBJECTIVE

The purpose of the present study was to determine whether partial D(2)-like agonists exhibit both antagonistic and agonistic actions during the preweanling period.

METHODS

In experiments 1 and 2 (examining the agonistic actions of terguride), preweanling rats were either given an escalating regimen of amphetamine to induce a state of amphetamine withdrawal or pretreated with the tyrosine hydroxylase inhibitor AMPT. Distance traveled was measured after rats were injected with saline, terguride (0.4-1.6 mg/kg), or the full D(2)-like receptor agonist NPA (0.01 mg/kg). In experiment 3 (examining the antagonistic actions of terguride), preweanling rats were pretreated with terguride 30 min before they were tested with saline, NPA (0.05 mg/kg), or amphetamine (1.5 mg/kg).

RESULTS

NPA had an exaggerated locomotor activating effect when tested under conditions of amphetamine withdrawal, while the partial D(2)-like agonist did not enhance distance traveled under any circumstance. Similarly, NPA increased and terguride did not affect the distance-traveled scores of AMPT-pretreated rats. In experiment 3, terguride pretreatment significantly reduced the distance traveled of amphetamine-treated and NPA-treated rats.

CONCLUSIONS

The behavioral evidence indicates that, during the preweanling period, terguride antagonizes D(2)-like post-synaptic receptors in a state of high dopaminergic tone; however, there is no evidence that terguride is capable of stimulating D(2)-like post-synaptic receptors during states of low dopaminergic tone.