Cardiac safety of methylphenidate versus amphetamine salts in the treatment of ADHD

Cardiovascular Safety of Amphetamine/Dextroamphetamine versus Methylphenidate in Older Adults

Background: Recent epidemiological data has shown a sharp increase in stimulant use among older adults, which is notable as older adults may be especially vulnerable to their cardiovascular effects. Results of recent studies have shown an increase in cardiovascular events among older adults using stimulants; however, little data exists comparing cardiovascular safety of these agents head-to-head. Objective: To determine if the incidence of serious cardiovascular events, including myocardial infarction (MI), stroke/transient ischemic attack (TIA), or arrhythmia, are different in patients taking amphetamine/dextroamphetamine compared with patients taking methylphenidate. Methods: Retrospective chart review of veterans 50 years and older at the Veterans Affairs North Texas Health Care System (VANTHCS) who were first prescribed a stimulant between 2015 and 2021. The primary outcome was the difference in composite cardiovascular events between amphetamine/dextroamphetamine and methylphenidate. Secondary outcomes were the composite cardiovascular endpoints compared individually (MI, stroke/TIA, or arrhythmia). Hazard ratios were calculated based off of a time-to-event analysis displayed using a Kaplan-Meier curve for primary and secondary outcomes. Results: 466 veterans were screened for inclusion, 30 were excluded, and 436 were included. There was no difference found in composite cardiovascular events between the 241 veterans in the amphetamine/dextroamphetamine group and the 195 veterans in the methylphenidate group with 12 (5%) vs 8 (4.1%) events respectively (P = .6635). There was also no difference in time-to-event analysis (P = .4966). Conclusion: In elderly veterans, there was no difference found in incidence of major cardiovascular events with the use of amphetamine/dextroamphetamine compared with methylphenidate.

Prescription amphetamines in people with opioid use disorder and co-occurring psychostimulant use disorder initiating buprenorphine: an analysis of treatment retention and overdose risk

BACKGROUND

Attention-deficit and hyperactivity disorder (ADHD) is frequently diagnosed in patients with substance use disorders (SUDs), including opioids. There remains concern about the safety and efficacy of prescription amphetamines (PAs) and their impact on effectiveness of opioid use disorder (OUD) treatment with buprenorphine.

OBJECTIVES

To assess the effect of PAs on OUD buprenorphine treatment retention and/or SUD-related emergency admission or drug-related poisonings.

METHODS

We used a retrospective cohort design with a secondary analysis of data from Merative MarketScan Commercial and Multi-State Medicaid Databases from 1 January 2006 to 31 December 2016. Individuals included were aged 12-64 years, had an OUD diagnosis and were prescribed buprenorphine. Our analysis used multivariable Cox regression to evaluate the relationship between PA receipt and time to buprenorphine discontinuation. The second part focused on subsamples of buprenorphine initiators who had either (1) any SUD-related emergency admissions or (2) drug-related poisoning. These outcomes were modelled as a function of PA exposure using conditional logistic regression models as part of a within-person, case-crossover design.

FINDINGS

Our sample had 90 269 patients with OUD (mean age 34.2 years (SD=11.3)) who initiated buprenorphine. Being prescribed a PA was associated with improved buprenorphine retention among individuals both with (adjusted HR (aHR) 0.91 (95% CI 0.86 to 0.97)) and without a concurrent psychostimulant use disorder (PSUD) (aHR 0.92 (95% CI 0.90 to 0.93)).

CONCLUSIONS

PA use was associated with improved buprenorphine retention in people with OUD with and without co-occurring PSUD. The risks of acute SUD-related events and drug-related poisonings associated with PA use did not differ when comparing PA-using days with days without PA use.

CLINICAL IMPLICATIONS

Patients with OUD on buprenorphine should receive treatment with a PA when indicated.

Cardiovascular Considerations for Stimulant Class Medications

The cardiovascular (CV) impact of stimulants has been examined for decades, with investigations ranging from small sample targeted studies of heart rate (HR) and blood pressure (BP), to large scale epidemiologic investigations. The preponderance of evidence is reassuring, albeit generally based on healthy samples using variable methodology, excluding those at theoretic high risk (eg, comorbid cardiac illness). Screening for theoretically vulnerable patients are recommended, as well as monitoring for CV symptoms and BP/HR, with shared inquiry/further evaluation if concerned. Future investigations to support the identification of risk are needed, while attention to stimulant-associated CV risk is an opportunity for clinicians to engage in general CV risk identification and intervention.

Cardiovascular Risk of Concomitant Use of Atypical Antipsychotics and Stimulants Among Commercially Insured Youth in the United States

Objectives: To investigate the risk of cardiovascular events associated with concomitant use of stimulants and atypical antipsychotics (AAPs) among youth and evaluate whether AAP dose and duration of concomitant use modifies the risk. Methods: We used IQVIA PharMetrics® Plus data from 2006 to 2015 to construct a retrospective cohort of commercially-insured youth aged 5-17 years old who initiated a stimulant medication. Time-varying concomitant stimulant/AAP use was defined as current, past and no concomitant use based on person months. The primary time-varying Cox proportional hazard regression analysis evaluated the risk of cardiovascular events comparing current concomitant use with past and no concomitant use, adjusted for baseline cardiovascular risk. A secondary analysis assessed the risk of cardiovascular events comparing AAP daily doses (<1, 1-2, >2 mg) and duration (<3, 3-6, >6 months) of current concomitant use to no concomitant use. Cardiovascular outcomes included severe (i.e., stroke, acute myocardial infarction, ischemic heart disease) and less severe (i.e., angina pectoris, cardiac dysrhythmias, transient cerebral ischemia, hypertensive disease, tachycardia, palpitations, syncope). Results: For this cohort of 61,438 youths, the incidence rate of severe cardiovascular events was 0.18 per 10,000 person-months, and all events occurred in no concomitant use months. The risk of less severe cardiovascular events was significantly higher in current concomitant users compared with no [HR: 2.59 (95%CI: 1.72, 3.90)] and past [HR: 1.89 (95%CI: 1.10, 3.24)] concomitant users. Compared to no concomitant use, the risk of less severe cardiovascular events was significantly higher at all AAP daily doses [HR: <1 mg: 2.82 (95%CI: 1.72, 4.61); 1-2 mg: 2.22 (95%CI: 1.16, 4.25); >2 mg: 2.65 (95%CI: 1.50, 4.71)]. The risk of less severe cardiovascular events significantly elevated for all duration of use and was higher for <3 months of concomitant use [HR: <3 months: 3.45 (95%CI: 2.17, 5.47) relative to 3-6 months: 2.60 (95%CI: 1.29, 5.25) or >6 months: 2.61 (95%CI: 1.59, 4.30)]. Conclusions: Severe cardiovascular events are rare. Concomitant stimulant/AAP use elevates the risk of less severe cardiovascular events. Periodic heart rate or blood pressure monitoring for youth on stimulant/AAP treatment may be warranted.

Cardiovascular Safety of Concomitant Use of Atypical Antipsychotics and Long-Acting Stimulants in Children and Adolescents With ADHD

OBJECTIVE

This study examined cardiovascular safety of concomitant use of long-acting stimulants (LAS) and atypical antipsychotics (AAP) in children and adolescents with Attention Deficit Hyperactivity Disorder (ADHD).

METHOD

The study used 2004-2007 IMS LifeLink™ claims data involving 6- to 16-year-old children with ADHD and at least one LAS prescription from July 2004 to December 2006. Time-dependent Cox regression analysis was performed to evaluate the risk of cardiovascular disease (CVD) events due to concomitant use of LAS and AAP.

RESULTS

The analytical cohort consisted of 37,903 children: 538 (1.9%) used LAS and AAP concurrently and the rest used LAS monotherapy. Time-dependent Cox regression analysis revealed no difference in CVD risk among concomitant users of LAS and AAP (hazard ratio = 1.19; 95% confidence interval = [0.60, 2.53]) when compared with users of LAS monotherapy.

CONCLUSION

Concomitant use of LAS and AAP was not associated with risk of CVD events in ADHD patients when compared with LAS monotherapy.

Methylphenidate for attention deficit hyperactivity disorder (ADHD) in children and adolescents - assessment of adverse events in non-randomised studies

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder in childhood. The psychostimulant methylphenidate is the most frequently used medication to treat it. Several studies have investigated the benefits of methylphenidate, showing possible favourable effects on ADHD symptoms, but the true magnitude of the effect is unknown. Concerning adverse events associated with the treatment, our systematic review of randomised clinical trials (RCTs) demonstrated no increase in serious adverse events, but a high proportion of participants suffered a range of non-serious adverse events.

OBJECTIVES

To assess the adverse events associated with methylphenidate treatment for children and adolescents with ADHD in non-randomised studies.

SEARCH METHODS

In January 2016, we searched CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, 12 other databases and two trials registers. We also checked reference lists and contacted authors and pharmaceutical companies to identify additional studies.

SELECTION CRITERIA

We included non-randomised study designs. These comprised comparative and non-comparative cohort studies, patient-control studies, patient reports/series and cross-sectional studies of methylphenidate administered at any dosage or formulation. We also included methylphenidate groups from RCTs assessing methylphenidate versus other interventions for ADHD as well as data from follow-up periods in RCTs. Participants had to have an ADHD diagnosis (from the 3rd to the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders or the 9th or 10th edition of theInternational Classification of Diseases, with or without comorbid diagnoses. We required that at least 75% of participants had a normal intellectual capacity (intelligence quotient of more than 70 points) and were aged below 20 years. We excluded studies that used another ADHD drug as a co-intervention.

DATA COLLECTION AND ANALYSIS

Fourteen review authors selected studies independently. Two review authors assessed risk of bias independently using the ROBINS-I tool for assessing risk of bias in non-randomised studies of interventions. All review authors extracted data. We defined serious adverse events according to the International Committee of Harmonization as any lethal, life-threatening or life-changing event. We considered all other adverse events to be non-serious adverse events and conducted meta-analyses of data from comparative studies. We calculated meta-analytic estimates of prevalence from non-comparative cohorts studies and synthesised data from patient reports/series qualitatively. We investigated heterogeneity by conducting subgroup analyses, and we also conducted sensitivity analyses.

MAIN RESULTS

We included a total of 260 studies: 7 comparative cohort studies, 6 of which compared 968 patients who were exposed to methylphenidate to 166 controls, and 1 which assessed 1224 patients that were exposed or not exposed to methylphenidate during different time periods; 4 patient-control studies (53,192 exposed to methylphenidate and 19,906 controls); 177 non-comparative cohort studies (2,207,751 participants); 2 cross-sectional studies (96 participants) and 70 patient reports/series (206 participants). Participants' ages ranged from 3 years to 20 years. Risk of bias in the included comparative studies ranged from moderate to critical, with most studies showing critical risk of bias. We evaluated all non-comparative studies at critical risk of bias. The GRADE quality rating of the evidence was very low.Primary outcomesIn the comparative studies, methylphenidate increased the risk ratio (RR) of serious adverse events (RR 1.36, 95% confidence interval (CI) 1.17 to 1.57; 2 studies, 72,005 participants); any psychotic disorder (RR 1.36, 95% CI 1.17 to 1.57; 1 study, 71,771 participants); and arrhythmia (RR 1.61, 95% CI 1.48 to 1.74; 1 study, 1224 participants) compared to no intervention.In the non-comparative cohort studies, the proportion of participants on methylphenidate experiencing any serious adverse event was 1.20% (95% CI 0.70% to 2.00%; 50 studies, 162,422 participants). Withdrawal from methylphenidate due to any serious adverse events occurred in 1.20% (95% CI 0.60% to 2.30%; 7 studies, 1173 participants) and adverse events of unknown severity led to withdrawal in 7.30% of participants (95% CI 5.30% to 10.0%; 22 studies, 3708 participants).Secondary outcomesIn the comparative studies, methylphenidate, compared to no intervention, increased the RR of insomnia and sleep problems (RR 2.58, 95% CI 1.24 to 5.34; 3 studies, 425 participants) and decreased appetite (RR 15.06, 95% CI 2.12 to 106.83; 1 study, 335 participants).With non-comparative cohort studies, the proportion of participants on methylphenidate with any non-serious adverse events was 51.2% (95% CI 41.2% to 61.1%; 49 studies, 13,978 participants). These included difficulty falling asleep, 17.9% (95% CI 14.7% to 21.6%; 82 studies, 11,507 participants); headache, 14.4% (95% CI 11.3% to 18.3%; 90 studies, 13,469 participants); abdominal pain, 10.7% (95% CI 8.60% to 13.3%; 79 studies, 11,750 participants); and decreased appetite, 31.1% (95% CI 26.5% to 36.2%; 84 studies, 11,594 participants). Withdrawal of methylphenidate due to non-serious adverse events occurred in 6.20% (95% CI 4.80% to 7.90%; 37 studies, 7142 participants), and 16.2% were withdrawn for unknown reasons (95% CI 13.0% to 19.9%; 57 studies, 8340 participants).

AUTHORS' CONCLUSIONS

Our findings suggest that methylphenidate may be associated with a number of serious adverse events as well as a large number of non-serious adverse events in children and adolescents, which often lead to withdrawal of methylphenidate. Our certainty in the evidence is very low, and accordingly, it is not possible to accurately estimate the actual risk of adverse events. It might be higher than reported here.Given the possible association between methylphenidate and the adverse events identified, it may be important to identify people who are most susceptible to adverse events. To do this we must undertake large-scale, high-quality RCTs, along with studies aimed at identifying responders and non-responders.

Blood pressure in children with attention deficit/hyperactivity disorder

Objectives

Children with attention deficit/hyperactivity disorder (ADHD) are frequently treated with psycho-stimulant agents causing a modest but significant increase in blood pressure and heart rate. The objective of this study was to define blood pressure characteristics in children with ADHD treated with a variety of medications in a community setup.

Methods

Children registered at a large paediatric clinic in Calgary, AB with documented histories of ADHD were randomly contacted. Consenting participants had standardized office BP measurements, ambulatory blood pressure monitoring (ABPM) studies and were asked to complete the sleep disturbance scale for children (SDSC) questionnaire. Findings were compared with data from the Canadian Health Measures Survey (CMHS).

Results

Fifty-five children (47 males) aged 7 to 17 years (average 11.6 ± 2.5 years) with an average BMI z-score of -0.37 ± 1.22 completed the study. All children were medicated, the majority (82%), with various types of stimulant agents. Elevated office BP values were more prevalent than in the CMHS; >90th percentile in 5 (9.1%) and >95th percentile in 3 (5.5%). ABPM confirmed 'white coat hypertension' in 3 (5.5%), masked hypertension in 2 (3.6%) and nondipping in 28 (51%). The SDSC score suggested that 43 (78%) children had disturbed sleep. Logistic regression modelling indicated that nondipping correlated with disturbed sleep.

Conclusion

The 'white coat' phenomenon may be responsible for increased prevalence of elevated rest/office BP values in children with ADHD. Prevalent sleep 'non-dipping' in this population is associated with sleep disturbances but clinical significance of this finding requires further investigation.

The pharmacology of amphetamine and methylphenidate: Relevance to the neurobiology of attention-deficit/hyperactivity disorder and other psychiatric comorbidities

Psychostimulants, including amphetamines and methylphenidate, are first-line pharmacotherapies for individuals with attention-deficit/hyperactivity disorder (ADHD). This review aims to educate physicians regarding differences in pharmacology and mechanisms of action between amphetamine and methylphenidate, thus enhancing physician understanding of psychostimulants and their use in managing individuals with ADHD who may have comorbid psychiatric conditions. A systematic literature review of PubMed was conducted in April 2017, focusing on cellular- and brain system-level effects of amphetamine and methylphenidate. The primary pharmacologic effect of both amphetamine and methylphenidate is to increase central dopamine and norepinephrine activity, which impacts executive and attentional function. Amphetamine actions include dopamine and norepinephrine transporter inhibition, vesicular monoamine transporter 2 (VMAT-2) inhibition, and monoamine oxidase activity inhibition. Methylphenidate actions include dopamine and norepinephrine transporter inhibition, agonist activity at the serotonin type 1A receptor, and redistribution of the VMAT-2. There is also evidence for interactions with glutamate and opioid systems. Clinical implications of these actions in individuals with ADHD with comorbid depression, anxiety, substance use disorder, and sleep disturbances are discussed.

Stimulants and Pediatric Cardiovascular Risk

OBJECTIVE

Concerns about serious cardiovascular (CV) events among stimulant-treated youth have led to clinical and policy debates. Accordingly, several population-based empirical studies have assessed the risk of CV events in children and adolescents treated with stimulants. The main objective of this review was to summarize findings and to evaluate the strengths and weaknesses of these population-based studies. In addition, we discuss the CV monitoring and policy implications for a clinically focused audience.

METHODS

A computerized literature search of Medline and PsycINFO was conducted for the calendar years 1990-2015 to identify population-based studies assessing stimulant treatment-emergent CV events in youth. Additional reports, peer-reviewed or gray literature, for example, government reports, were also included.

RESULTS

Nine population-based studies (one case-control and eight retrospective cohort designs) were included in this review. The case-control study compared sudden unexplained death cases to age-matched controls (motor vehicle passenger deaths) with respect to prior stimulant use and found a significant association (odds ratio = 7.4 [95% CI: 1.4-74.9]). By contrast, most retrospective cohort studies assessed the risk of serious CV events (i.e., sudden death, myocardial infarction, and stroke) and did not find an association with current stimulant exposure. The absolute rate for these serious events was low, but other data support risk. For example, cardiac-related emergency department visits showed a 20% increased risk for current stimulant users compared with nonusers in one study, and another study showed a 64% and 90% increased risk for concurrent use of stimulants with antidepressants and antipsychotics, respectively. Similarly, in another study, compared with nonusers, stimulant users had twofold greater odds of CV-related inpatient or outpatient services.

CONCLUSION

In the face of mixed results from population-based safety studies, this review supports the inclusion of baseline and ongoing monitoring of cardiac status to assure a favorable benefit risk profile for stimulant users, particularly in concomitant regimens with antipsychotics and antidepressants.

ADHD medications and cardiovascular adverse events in children and adolescents: cross-national comparison of risk communication in drug labeling

PURPOSE

Regulators approve written medical information for healthcare professionals and consumers, but the consistency of these sources has not been studied. We investigated the consistency of information regarding four cardiovascular risks of attention-deficit/hyperactivity disorder (ADHD) medications approved in four countries.

METHODS

Professional and consumer product labeling for five ADHD medications approved in Australia, Canada, the UK, and the USA were obtained in March/April 2016. Language describing the relationship between medication and elevated blood pressure and/or heart rate, myocardial infarction, stroke, and sudden death was extracted verbatim and classified into one of four categories based on the described relationship between medication and adverse event: "confirmed," "unconfirmed," "mixed," and "not mentioned." We judged the consistency of messages delivered to healthcare professionals and consumers as either "consistent" or "inconsistent."

RESULTS

We obtained 20 healthcare professional labels and 20 corresponding consumer labels for the five ADHD medications registered in all four countries. Not all professional and consumer labeling contained language regarding all four adverse events. Of the 80 theoretically evaluable drug-risk pairs, 38 (48%) were not evaluable because of absence of mention of the adverse event in the consumer label. For the remaining 42, the potential causal relationship was expressed consistently in professional and consumer labeling in 25 (60%) cases. The cardiovascular risk profile was not described consistently across all four countries for any of the five drugs.

CONCLUSIONS

Product labeling provides healthcare professionals and consumers with inconsistent messages regarding the potential causal relationship between stimulant use and specific cardiovascular risks in children and adolescents. Copyright © 2017 John Wiley & Sons, Ltd.

Pharmacoepidemiological safety studies in children: a systematic review

Purpose

In order to identify challenges in pediatric pharmacoepidemiological safety studies, we assessed the characteristics of such (published) studies.

Methods

Relevant articles from inception to 2013 were retrieved from Embase and Medline. We sequentially screened titles, abstracts and full texts with independent validation. We systematically collected data regarding general information, study methods and results.

Results

Out of 4825 unique articles, 268 full texts (5.6%) were retained; 147 (54.9%) pertained to drugs rather than vaccines. Considering the 268 studies, 202 (75.4%) concerned children and adolescents (2 to 11 years) and 14 (5.3%) included preterm newborns. Most studies originated from North America (154 [57.5%]) or Europe (92 [34.3%]). Only 47 studies (17.5%) were privately funded. The majority (174 [64.9%]) were cohort studies. Out of 268 studies, 196 (73.1%) collected data retrospectively; paper medical charts were the most common data source for the exposures (85 [31.7%]) and outcomes (122 [45.5%]). Only 3 (2.0%) drug‐only studies investigated rarely used drugs. Considering all 268 studies, only 27 (10.1%) reported sample size or power calculation. Most (75 [51.0%]) drug‐only studies corrected confounding by multivariate modeling unlike stratification in 66 (55.9%) vaccine‐only studies. Considering 75 child‐only studies without any statistically significant result, 41 (54.7%) did not discuss lack of power.

Conclusions

Although the field of pediatric pharmacoepidemiology is steadily developing evaluation seldom includes neonates, is mainly focused on few drug classes and safety outcomes and concerns mainly drug use in developed countries. Small study size is a specific challenge in pediatrics. Reporting should be improved. © 2016 The Authors. Pharmacoepidemiology and Drug Safety Published by John Wiley & Sons Ltd.

Predictors of concomitant use of antipsychotics and stimulants and its impact on stimulant persistence in pediatric attention deficit hyperactivity disorder

BACKGROUND

Concomitant use of stimulants and atypical antipsychotics is common in pediatric attention deficit hyperactivity disorder (ADHD). However, little is known about the determinants of concomitant use and its utility in the management of pediatric ADHD.

OBJECTIVES

To (a) examine predictors of concomitant stimulant and atypical antipsychotic use and (b) evaluate the impact of concomitant atypical antipsychotic use on the persistence of stimulants in children and adolescents diagnosed with ADHD.

METHODS

The retrospective cohort study was conducted using 4 years (January 2004-December 2007) of IMS LifeLink claims data. The study population included children and adolescents aged 6-16 years with a diagnosis of ADHD and those who initiated long-acting stimulants (LAS) from July 2004 to December 2006. Patients were followed for 1 year after index stimulant use. Concomitant use was defined as the concurrent prescription for LAS and atypical antipsychotic agents with at least 14 days overlap after the index LAS claim. Persistence was measured by summing the total number of days a patient remained on the index LAS from the index prescription date with an allowable gap of no more than 30 days. Multiple logistic regression within the conceptual framework of the Andersen Behavioral Model was performed to determine the predictors of concomitant stimulant and atypical antipsychotic use. Multivariate Cox proportional hazards regression within the conceptual framework of the Andersen Behavioral Model was used to examine the impact of concomitant atypical antipsychotic use on persistence of stimulants.

RESULTS

The study cohort consisted of 39,981 children who initiated LAS treatment. Most (96.10%) received LAS monotherapy, and 3.90% received LAS and atypical antipsychotic concomitantly. The multiple logistic regression analysis found that gender, health insurance, region, year of cohort entry, season, physician specialty, coexisting mental health conditions, and general mental health status influenced the concomitant use of LAS and atypical antipsychotic agents. Bivariate analyses revealed that concomitant users had longer persistence (by 71 days) than the stimulant-alone users. Cox proportional hazards regression revealed that concomitant atypical antipsychotic was associated with improvement in LAS persistence by 15% (HR = 0.85, 95% CI = 0.76-0.94) in comparison with the LAS recipients who did not use atypical antipsychotic concomitantly. Other factors such as age, region, season, coexisting mental health conditions, use of comedications, and general mental health status influenced the LAS treatment persistence among children and adolescents.

CONCLUSIONS

Various predisposing, enabling, and need factors were associated with the concomitant stimulant and atypical antipsychotic use. Concomitant use of atypical antipsychotics was associated with improved LAS treatment persistence in children and adolescents with ADHD.

Assessment of potential cardiovascular risks of methylphenidate in comparison with sibutramine: do we need a SCOUT (trial)?

With the recent approval of methylphenidate (MPH) for treating attention-deficit/hyperactivity disorder (ADHD) in adults, the number of patients exposed will increase tremendously. The ongoing debate on the cardiovascular safety of MPH has triggered two large retrospective cohort studies in children and adolescents as well as in young to middle-aged adults. These studies looked into serious cardiovascular events (sudden cardiac death, acute myocardial infarction and stroke) as primary endpoints and concluded that MPH was safe after a mean duration of 2.1 years of follow-up in children and adolescents and mean duration of 0.33 years of current use in adults. The results are encouraging with respect to the short- and medium-term use of MPH. Without the inherent limitations of retrospective cohort studies, a prospective randomized, double-blind, placebo-controlled, multicenter trial in individuals stratified for cardiovascular risk factors would allow for an optimized risk assessment. With many millions of patients treated per year and drawing parallels to the lately discovered risks of sibutramine, another sympathomimetic with an overlapping mode of action and similar side effects on heart rate and blood pressure, we hypothesize that such a trial might be a dedicated risk mitigation strategy for public health. A critical assessment of cardiovascular side effects of MPH appears particularly warranted, because ADHD is associated with obesity, smoking and poor health in general. We summarize recent findings with the focus on cardiovascular risks of MPH in humans; we additionally analyze the limited number of rodent studies that have addressed cardiovascular risks of MPH.

Attention-deficit/hyperactivity disorder treatment: what are the long-term cardiovascular risks?

INTRODUCTION

This drug safety review provides an update on the long-term cardiovascular risks of therapeutic stimulant class medication for children and adults with attention-deficit/hyperactivity disorder (ADHD).

AREAS COVERED

Relevant literature on the long-term (defined as ≥ 12 months) cardiovascular effects of stimulant class medications for ADHD was sought using PubMed searches for clinical literature, epidemiological reports, as well as reviews of post-marketing data and clinical guidelines/consensus statements. Comparison was made to the non-stimulant atomoxetine.

EXPERT OPINION

Long-term cardiovascular risks of stimulants for healthy children and adults with ADHD are limited to minor mean elevations in blood pressure (≤ 7 mmHg) and heart rate (≤ 10 bpm). In a sizeable minority of individuals these elevations are greater and/or reach a clinical threshold. Subjective complaints may also be anticipated during long-term treatment, yet without an increase in serious cardiac outcomes above background rates per age. Future research is needed on possible latent or cumulative cardiovascular risks in healthy individuals, as well as the longer-term cardiovascular safety in vulnerable populations.

Cardiac autonomic dysfunction and arterial stiffness among children and adolescents with attention deficit hyperactivity disorder treated with stimulants

OBJECTIVE

To compare markers of cardiovascular health in youth diagnosed with attention deficit hyperactivity disorder (ADHD) by the use of stimulant medication with healthy controls.

STUDY DESIGN

Children and adolescents (n = 85; mean age 11.2 ± 2.8 years; 66 boys) diagnosed with ADHD using a stimulant and 53 siblings without ADHD (mean age 11.1 ± 3.8 years; 28 boys) were included in this cross-sectional study. Measured variables included blood pressure, heart rate (HR), HR variability: SD of the RR interval and low frequency to high frequency ratio, carotid-radial pulse wave velocity, carotid artery augmentation index (AIx), radial artery AIx, brachial artery flow-mediated dilation, and digital reactive hyperemic index.

RESULTS

Compared with control patients, participants with ADHD had greater resting systolic blood pressure (3.9 mm Hg, 95% CI [1.2-6.7], P = .005), diastolic blood pressure (5.5 mm Hg, 95% CI [3.2-7.8], P < .001), HR (9.2 beats/min, 95% CI [6.0-12.3], P < .001), low frequency to high frequency ratio (0.55, 95% CI [0.22-0.89], P = .001), carotid AIx (7.2%, 95% CI [1.9-12.5], P = .008), and pulse wave velocity (0.36 m/s, 95% CI [-0.05, 0.78], P = .089), and lower SD of the RR interval (-33.7 milliseconds, 95% CI [-46.1, -21.3], P < .001). Neither flow-mediated dilation nor reactive hyperemic index was significantly different.

CONCLUSIONS

Children and adolescents being treated with a stimulant medication for ADHD exhibited signs of altered cardiac autonomic function, characterized by increased sympathetic tone, and showed evidence of arterial stiffening.

Cardiovascular safety of stimulants in children with attention-deficit/hyperactivity disorder: a nationwide prospective cohort study

OBJECTIVE

The purpose of this study was to determine whether stimulant users are at higher risk of a later cardiovascular event than are non-users, examining this association in both a national cohort and a population-based sample of children and adolescents diagnosed with attention-deficit/hyperactivity disorder (ADHD). We also aim to examine a possible dose-response relationship in such an association.

METHODS

We conducted a longitudinal, prospective cohort study of all children born in Denmark between 1990 and 1999. Within this cohort, children with ADHD were identified. Data from national health registers on psychiatric and somatic diagnoses, stimulant prescriptions, cardiovascular risk factors, pre- and perinatal and sociodemographic covariates in all children and their parents were merged, using the unique personal identification number. Hazard ratios (HR) for cardiovascular events were estimated using Cox regression, adjusted for other known risk factors.

RESULTS

In the total population (n=714,258 contributing a total of 6,767,982 person-years) use of stimulants increased the risk of a cardiovascular event; adjusted HR=1.83 (1.10-3.04). In children with ADHD (n=8300) stimulant treatment also increased the risk of a cardiovascular event (adjusted HR=2.20 [2.15-2.24]), with a complex time-dependent dose-response relationship.

CONCLUSIONS

This is the first nationwide cohort study of the cardiovascular safety of stimulants in children and adolescents, and it represents, to our knowledge, the longest prospective follow-up study. Cardiovascular events were rare but twice as likely in stimulant users as in non-users, both in the total national population and in children with ADHD. We found a complex, time- and dose-dependent interrelationship between cardiovascular adverse events and stimulant treatment in children and adolescents. Our results suggest a safety signal with an increased risk of cardiovascular disease associated with stimulant treatment in children and adolescents, even after adjusting for a number of potential confounders.

Cardiovascular safety of stimulants in children: findings from recent population-based cohort studies

The past decade has seen a heated debate over the cardiac safety of central nervous system stimulants in the treatment of ADHD. This review discusses five controlled population-based studies that investigated this risk in children in the United States. All studies utilized administrative claims data of private or public insurance to compare risk of stimulant use to non-use. Two studies with smaller sample size lacked the ability to investigate serious events but report a slightly increased risk of emergency department visits attributed to cardiac symptoms such as tachycardia or palpitation. Three studies that enrolled more than one million patients found no association between stimulants and composite endpoints of sudden cardiac death, myocardial infarction, stroke and ventricular arrhythmia. The studies concur that background rates of serious cardiovascular events in children are extremely small. No study exceeded an average follow-up of two years, prohibiting inferences about long-term effects of stimulants.

Long-acting stimulants for treatment of attention-deficit/hyperactivity disorder: a focus on extended-release formulations and the prodrug lisdexamfetamine dimesylate to address continuing clinical challenges

Individuals with attention-deficit/hyperactivity disorder (ADHD) show pervasive impairments across family, peer, and school or work functioning that may extend throughout the day. Psychostimulants are highly effective medications for the treatment of ADHD, and the development of long-acting stimulant formulations has greatly expanded the treatment options for individuals with ADHD. Strategies for the formulation of long-acting stimulants include the combination of immediate-release and delayed-release beads, and an osmotic-release oral system. A recent development is the availability of the first prodrug stimulant, lisdexamfetamine dimesylate (LDX). LDX itself is inactive but is cleaved enzymatically, primarily in the bloodstream, to release d-amphetamine (d-AMP). Several clinical trials have demonstrated that long-acting stimulants are effective in reducing ADHD symptoms compared with placebo. Analog classroom and simulated adult workplace environment studies have shown that long-acting stimulants produce symptom reduction for at least 12 h. Long-acting stimulants exhibit similar tolerability and safety profiles to short-acting equivalents. While variations in gastric pH and motility can alter the availability and absorption of stimulants released from long-acting formulations, the systemic exposure to d-AMP following LDX administration is unlikely to be affected by gastrointestinal conditions. Long-acting formulations may also improve adherence and lower abuse potential compared with their short-acting counterparts. The development of long-acting stimulants provides physicians with an increased range of medication options to help tailor treatment for individuals with ADHD.

Abuse and dependence liability analysis of methylphenidate in the spontaneously hypertensive rat model of attention-deficit/hyperactivity disorder (ADHD): what have we learned?

Methylphenidate is the most prescribed stimulant medication for attention-deficit/hyperactivity disorder (ADHD). Despite the well documented clinical benefits of the drug, several questions remain unanswered concerning the effects of extended methylphenidate use (e.g. can methylphenidate be abused by ADHD patients? does repeated methylphenidate treatment produce addiction?). Preclinical studies can help address the long-term safety of clinical treatments, moreover animal studies provide valuable information on the details of drug actions. The spontaneously hypertensive rat (SHR), bred from normotensive Wistar Kyoto rat strain, is considered as the best validated and the most widely used animal model of ADHD. We reviewed the findings of research reports that investigated the abuse and dependence liability of methylphenidate in SHR. In particular, we surveyed the studies which investigated the effects of methylphenidate pretreatment on subsequent methylphenidate-induced conditioned place preference or self-administration for they may give insights into the abuse or dependence liability of long-term methylphenidate treatment in ADHD.

Risk of serious cardiovascular problems with medications for attention-deficit hyperactivity disorder

Attention-deficit hyperactivity disorder (ADHD) is a chronic neurodevelopmental disorder characterized by persistent symptoms of inattention, hyperactivity and/or impulsivity. The proportion of patients diagnosed with ADHD receiving pharmacological treatments has increased enormously in recent years. Despite the well established efficacy and the good safety and tolerability profile, there is concern about the potential for rare but serious cardiovascular adverse events, as well as sudden cardiac death, with pharmacotherapies used for treating ADHD in children, adolescents and adults. The present paper aims to comprehensively and critically review the published evidence on the controversial association between medications approved for treating patients with ADHD and the risk of serious cardiovascular problems, specifically the risk of corrected QT interval (QTc) prolongation, and the risk of sudden cardiac death. A comprehensive search of relevant databases (PubMed, EMBASE and PsychINFO) was conducted to identify studies published in peer-reviewed journals until 21 July 2012. Clinical reports, as well as retrospective or prospective population-based studies with children, adolescents or adults as participants, of pharmacotherapies for ADHD reporting cardiovascular adverse events were included. Stimulant medications for ADHD, including methylphenidate and amphetamine derivatives, are generally safe and well tolerated. Small but statistically significant increases in blood pressure (BP) and heart rate (HR) are among the adverse events of stimulant treatment in all age groups. Similarly, the non-stimulant medication atomoxetine has also been associated with increased HR and BP, although as is the case with stimulants, these are generally minor, time limited and of minor clinical significance in children, adolescents or adults. Growing evidence suggests that these medications do not cause sudden and unexpected cardiac death or serious cardiovascular problems including statistically or clinically significant increases in QTc, at therapeutic doses in ADHD patients across the lifespan. Small decreases in mean systolic BP, diastolic BP and HR have been observed in studies with guanfacine-extended release (-XR) or clonidine-XR, two α(2)-adrenergic receptor agonists, administered alone or in combination with psychostimulants to children and adolescents with ADHD. There are also no statistically or clinically significant increases in QTc associated with clonidine or guanfacine. There are no reports of torsades de pointes clearly and directly related to medications used for treating ADHD in patients of all age groups. The risk for serious cardiovascular adverse events, including statistically or clinically significant increases in QTc, and sudden cardiac death associated with stimulants, atomoxetine or α(2)-adrenergic agonists prescribed for ADHD is extremely low and the benefits of treating individual patients with ADHD, after an adequate assessment, outweigh the risks. However, great caution is advised when considering stimulant and non-stimulant medications for patients of any age with a diagnosis of ADHD and a personal or family history or other known risk factors for cardiovascular disease.

[The medical treatment of attention deficit hyperactivity disorder (ADHD) with amphetamines in children and adolescents]

INTRODUCTION

Psychostimulants (methylphenidate and amphetamines) are the drugs of first choice in the pharmacological treatment of children and adolescents with attention deficit hyperactivity disorder (ADHD).

OBJECTIVE

We summarize the pharmacological characteristics of amphetamines and compare them with methylphenidate, special emphasis being given to a comparison of effects and side effects of the two substances. Finally, we analyze the abuse and addiction risks.

METHODS

Publications were chosen based on a Medline analysis for controlled studies and meta-analyses published between 1980 and 2011; keywords were amphetamine, amphetamine salts, lisdexamphetamine, controlled studies, and metaanalyses.

RESULTS AND DISCUSSION

Amphetamines generally exhibit some pharmacologic similarities with methylphenidate. However, besides inhibiting dopamine reuptake amphetamines also cause the release of monoamines. Moreover, plasma half-life is significantly prolonged. The clinical efficacy and tolerability of amphetamines is comparable to methylphenidate. Amphetamines can therefore be used if the individual response to methylphenidate or tolerability is insufficient before switching to a nonstimulant substance, thus improving the total response rate to psychostimulant treatment. Because of the high abuse potential of amphetamines, especially in adults, the prodrug lisdexamphetamine (Vyvanse) could become an effective treatment alternative. Available study data suggest a combination of high clinical effect size with a beneficial pharmacokinetic profile and a reduced abuse risk.

CONCLUSIONS

In addition to methylphenidate, amphetamines serve as important complements in the psychostimulant treatment of ADHD. Future studies should focus on a differential comparison of the two substances with regard to their effects on different core symptom constellations and the presence of various comorbidities.

Do prescription stimulants increase the risk of adverse cardiovascular events?: A systematic review

BACKGROUND

There is increasing concern that prescription stimulants may be associated with adverse cardiovascular events such as stroke, myocardial infarction, and sudden death. Public health concerns are amplified by increasing use of prescription stimulants among adults.

METHODS

The objective of this study was to conduct a systematic review of the evidence of an association between prescription stimulant use and adverse cardiovascular outcomes. PUBMED, MEDLINE, EMBASE and Google Scholar searches were conducted using key words related to these topics (MESH): ADHD; Adults; Amphetamine; Amphetamines; Arrhythmias, Cardiac; Cardiovascular Diseases; Cardiovascular System; Central Nervous Stimulants; Cerebrovascular; Cohort Studies; Case-control Studies; Death; Death, Sudden, Cardiac; Dextroamphetamine; Drug Toxicity; Methamphetamine; Methylphenidate; Myocardial Infarction; Stimulant; Stroke; Safety. Eligible studies were population-based studies of children, adolescents, or adults using prescription stimulant use as the independent variable and a hard cardiovascular outcome as the dependent variable.

RESULTS

Ten population-based observational studies which evaluated prescription stimulant use with cardiovascular outcomes were reviewed. Six out of seven studies in children and adolescents did not show an association between stimulant use and adverse cardiovascular outcomes. In contrast, two out of three studies in adults found an association.

CONCLUSIONS

Findings of an association between prescription stimulant use and adverse cardiovascular outcomes are mixed. Studies of children and adolescents suggest that statistical power is limited in available study populations, and the absolute risk of an event is low. More suggestive of a safety signal, studies of adults found an increased risk for transient ischemic attack and sudden death/ventricular arrhythmia. Interpretation was limited due to differences in population, cardiovascular outcome selection/ascertainment, and methodology. Accounting for confounding and selection biases in these studies is of particular concern. Future studies should address this and other methodological issues.

Persistence of stimulants in children and adolescents with attention-deficit/hyperactivity disorder

OBJECTIVE

To examine the persistence of three newly initiated stimulant preparations among Medicaid children and adolescents with attention-deficit/hyperactivity disorder (ADHD) diagnosis.

METHODS

A retrospective longitudinal claims analysis was conducted by using Medicaid analytical eXtract data of four states. The study focused on patients between 6 and 19 years of age with ADHD diagnosis and a stimulant prescription from January 2003 to December 2005. Stimulants were grouped into short-acting stimulants (SAS), intermediate-acting stimulants (IAS), and long-acting stimulants (LAS). Persistence was measured by totaling the number of days the patient remained on the index stimulant therapy from the index prescription date provided the refill gap between two consecutive stimulant claims was no more than 30 days. All the stimulant recipients were uniformly followed for 1 year (365 days). Survival time ratios (STR) were calculated by using accelerated failure time models to examine variation in index stimulant persistence for each stimulant class.

RESULTS

Among the 46,135 patients with ADHD continuously followed for 1 year, 8,260 were SAS users, 4,314 were IAS users, and 33,561 were LAS users. Children who received IAS medications had 4% shorter persistence (STR, 0.96 [95% confidence interval [CI], 0.93-0.98]) when compared with those who received SAS medications, whereas those who received index LAS medications had 29% longer persistence (STR, 1.29 [95% CI, 1.27-1.32]). Multivariate accelerated failure time models revealed that Blacks and Hispanics had consistently lower persistence than their counterparts. Foster care was positively associated with index stimulant persistence in the three stimulant types. Further, addition of another stimulant and other psychotropic medications significantly improved persistence of index stimulant in all three stimulant classes.

CONCLUSIONS

LAS had comparatively longer persistence than other stimulants. An understanding of demographic and clinical characteristics that influence treatment continuation can help improve stimulant persistence rates in ADHD.

Toxicity of amphetamines: an update

Amphetamines represent a class of psychotropic compounds, widely abused for their stimulant, euphoric, anorectic, and, in some cases, emphathogenic, entactogenic, and hallucinogenic properties. These compounds derive from the β-phenylethylamine core structure and are kinetically and dynamically characterized by easily crossing the blood-brain barrier, to resist brain biotransformation and to release monoamine neurotransmitters from nerve endings. Although amphetamines are widely acknowledged as synthetic drugs, of which amphetamine, methamphetamine, and 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) are well-known examples, humans have used natural amphetamines for several millenniums, through the consumption of amphetamines produced in plants, namely cathinone (khat), obtained from the plant Catha edulis and ephedrine, obtained from various plants in the genus Ephedra. More recently, a wave of new amphetamines has emerged in the market, mainly constituted of cathinone derivatives, including mephedrone, methylone, methedrone, and buthylone, among others. Although intoxications by amphetamines continue to be common causes of emergency department and hospital admissions, it is frequent to find the sophism that amphetamine derivatives, namely those appearing more recently, are relatively safe. However, human intoxications by these drugs are increasingly being reported, with similar patterns compared to those previously seen with classical amphetamines. That is not surprising, considering the similar structures and mechanisms of action among the different amphetamines, conferring similar toxicokinetic and toxicological profiles to these compounds. The aim of the present review is to give an insight into the pharmacokinetics, general mechanisms of biological and toxicological actions, and the main target organs for the toxicity of amphetamines. Although there is still scarce knowledge from novel amphetamines to draw mechanistic insights, the long-studied classical amphetamines-amphetamine itself, as well as methamphetamine and MDMA, provide plenty of data that may be useful to predict toxicological outcome to improvident abusers and are for that reason the main focus of this review.

Norepinephrine transporter -3081(A/T) and alpha-2A-adrenergic receptor MspI polymorphisms are associated with cardiovascular side effects of OROS-methylphenidate treatment

The purpose of this study was to investigate a possible association between norepinephrine genes and cardiovascular side effects of the Osmotic Controlled-Release Oral Delivery System-methylphenidate (OROS-MPH) in Korean children with attention-deficit/hyperactivity disorder (ADHD). One hundred and one children with ADHD (8.7 ± 1.7 years) were recruited from child psychiatric centers at six university hospitals in South Korea. All participants were drug-naive ADHD children treated with OROS-MPH for 12 weeks. During the treatment period the investigators titrated the OROS-MPH dosage on the basis of symptom severity and side effects. Resting heart rate (HR), diastolic blood pressure (DBP), and systolic blood pressure (SBP) were examined before and after treatment. The percentage change score (post-treatment - pretreatment/pretreatment × 100) of each parameter was calculated. Genotyping of SLC6A2 -3081(A/T) and G1287A, and alpha-2A-adrenergic receptor (ADRA2A) MspI and DraI polymorphisms was performed. Clinically significant changes were not found in cardiovascular monitoring during the course of treatment. An increase of HR after OROS-MPH treatment was found to be statistically significant (t = 3.54, p = 0.001). Changes in SBP and DBP were not significant and no specific change was found in the ECGs. However, an additive regression analysis demonstrated a significant association between SLC6A2 -3081(A/T) and percentage change in HR post-treatment (p = 0.01) after controlling for age, gender, dosage of MPH and response and baseline pulse rate. Children with ADHD having the T/T genotype of SLC6A2 showed a 12.5% increase in HR compared to baseline, whereas children with the A/T or A/A genotype showed a 3.5% and 2.5% increase after OROS-MPH treatment, respectively. There was also a significant association between the ADRA2A MspI genotype and percentage change of DBP post-treatment after controlling for age, gender, dosage of MPH and response and baseline DBP (p = 0.009). Children with ADHD having the C/C genotype of ADRA2A MspI showed an 18.5% increase in DBP compared to baseline, but children with the G/G or G/C genotype showed a 0.2% decrease after OROS-MPH treatment. The overall cardiovascular effects of OROS-MPH were modest. However, our findings show a positive association between norepinephrine-related gene polymorphisms and cardiovascular response induced by MPH in Korean children with ADHD. Consideration must be given to such children or adults with specific norepinephrine-related genotypes, especially if they show significant changes in HR or DBP after OROS-MPH administration.

An update on the pharmacotherapy of attention-deficit/hyperactivity disorder in adults

Adults with attention-deficit/hyperactivity disorder (ADHD) are more frequently presenting for diagnosis and treatment. Medication is considered to be appropriate among available treatments for ADHD; however, the evidence supporting the use of pharmacotherapeutics for adults with ADHD remains less established. In this article, the effectiveness and dosing parameters of the various agents investigated for adult ADHD are reviewed. In adults with ADHD, short-term improvements in symptomatology have been documented through the use of stimulants and antidepressants. Studies suggest that methylphenidate and amphetamine maintained an immediate onset of action, whereas the ADHD response to the nonstimulants appeared to be delayed. At a group level, there appears to be some, albeit not entirely consistent, dose-dependent responses to amphetamine and methylphenidate. Generally speaking, variability in diagnostic criteria, dosing parameters and response rates between the various studies was considerable, and most studies were of a relatively short duration. The aggregate literature shows that the stimulants and catecholaminergic nonstimulants investigated had a clinically significant beneficial effect on treating ADHD in adults.

Stimulants and cardiovascular events in youth with attention-deficit/hyperactivity disorder

OBJECTIVE

This study examined associations between stimulant use and risk of cardiovascular events and symptoms in youth with attention-deficit/hyperactivity disorder and compared the risks associated with methylphenidate and amphetamines.

METHOD

Claims were reviewed of privately insured young people 6 to 21 years old without known cardiovascular risk factors (n = 171,126). A day-level cohort analysis evaluated the risk of cardiovascular events after a diagnosis of attention-deficit/hyperactivity disorder in relation to stimulant exposures. Based on filled stimulant prescriptions, follow-up days were classified as current, past, and no stimulant use. Endpoints included an emergency department or inpatient diagnosis of angina pectoris, cardiac dysrhythmia, or transient cerebral ischemia (cardiac events) or tachycardia, palpitations, or syncope (cardiac symptoms).

RESULTS

There were 0.92 new cardiac events and 3.08 new cardiac symptoms per 1,000,000 days of current stimulant use. Compared with no stimulant use (reference group), the adjusted odds ratios of cardiac events were 0.69 (95% confidence interval 0.42-1.12) during current stimulant use and 1.18 (95% CI 0.83-1.66) during past stimulant use. The corresponding adjusted odds ratios for cardiac symptoms were 1.18 (95% CI 0.89-1.59) for current and 0.93 (95% CI 0.71-1.21) for past stimulant use. No significant differences were observed in risks of cardiovascular events (2.14, 95% CI 0.82-5.63) or symptoms (1.08, 95% CI 0.66-1.79) for current methylphenidate use compared with amphetamine use (reference group).

CONCLUSIONS

Clinical diagnoses of cardiovascular events and symptoms were rare and not associated with stimulant use. The results help to allay concerns over the cardiovascular safety of stimulant treatment for attention-deficit/hyperactivity disorder in young people without known pre-existing risk factors.

ADHD medications and risk of serious cardiovascular events in young and middle-aged adults

CONTEXT

More than 1.5 million US adults use stimulants and other medications labeled for treatment of attention-deficit/hyperactivity disorder (ADHD). These agents can increase heart rate and blood pressure, raising concerns about their cardiovascular safety.

OBJECTIVE

To examine whether current use of medications prescribed primarily to treat ADHD is associated with increased risk of serious cardiovascular events in young and middle-aged adults.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective, population-based cohort study using electronic health care records from 4 study sites (OptumInsight Epidemiology, Tennessee Medicaid, Kaiser Permanente California, and the HMO Research Network), starting in 1986 at 1 site and ending in 2005 at all sites, with additional covariate assessment using 2007 survey data. Participants were adults aged 25 through 64 years with dispensed prescriptions for methylphenidate, amphetamine, or atomoxetine at baseline. Each medication user (n = 150,359) was matched to 2 nonusers on study site, birth year, sex, and calendar year (443,198 total users and nonusers).

MAIN OUTCOME MEASURES

Serious cardiovascular events, including myocardial infarction (MI), sudden cardiac death (SCD), or stroke, with comparison between current or new users and remote users to account for potential healthy-user bias.

RESULTS

During 806,182 person-years of follow-up (median, 1.3 years per person), 1357 cases of MI, 296 cases of SCD, and 575 cases of stroke occurred. There were 107,322 person-years of current use (median, 0.33 years), with a crude incidence per 1000 person-years of 1.34 (95% CI, 1.14-1.57) for MI, 0.30 (95% CI, 0.20-0.42) for SCD, and 0.56 (95% CI, 0.43-0.72) for stroke. The multivariable-adjusted rate ratio (RR) of serious cardiovascular events for current use vs nonuse of ADHD medications was 0.83 (95% CI, 0.72-0.96). Among new users of ADHD medications, the adjusted RR was 0.77 (95% CI, 0.63-0.94). The adjusted RR for current use vs remote use was 1.03 (95% CI, 0.86-1.24); for new use vs remote use, the adjusted RR was 1.02 (95% CI, 0.82-1.28); the upper limit of 1.28 corresponds to an additional 0.19 events per 1000 person-years at ages 25-44 years and 0.77 events per 1000 person-years at ages 45-64 years.

CONCLUSIONS

Among young and middle-aged adults, current or new use of ADHD medications, compared with nonuse or remote use, was not associated with an increased risk of serious cardiovascular events. Apparent protective associations likely represent healthy-user bias.

ADHD drugs and serious cardiovascular events in children and young adults

BACKGROUND

Adverse-event reports from North America have raised concern that the use of drugs for attention deficit-hyperactivity disorder (ADHD) increases the risk of serious cardiovascular events.

METHODS

We conducted a retrospective cohort study with automated data from four health plans (Tennessee Medicaid, Washington State Medicaid, Kaiser Permanente California, and OptumInsight Epidemiology), with 1,200,438 children and young adults between the ages of 2 and 24 years and 2,579,104 person-years of follow-up, including 373,667 person-years of current use of ADHD drugs. We identified serious cardiovascular events (sudden cardiac death, acute myocardial infarction, and stroke) from health-plan data and vital records, with end points validated by medical-record review. We estimated the relative risk of end points among current users, as compared with nonusers, with hazard ratios from Cox regression models.

RESULTS

Cohort members had 81 serious cardiovascular events (3.1 per 100,000 person-years). Current users of ADHD drugs were not at increased risk for serious cardiovascular events (adjusted hazard ratio, 0.75; 95% confidence interval [CI], 0.31 to 1.85). Risk was not increased for any of the individual end points, or for current users as compared with former users (adjusted hazard ratio, 0.70; 95% CI, 0.29 to 1.72). Alternative analyses addressing several study assumptions also showed no significant association between the use of an ADHD drug and the risk of a study end point.

CONCLUSIONS

This large study showed no evidence that current use of an ADHD drug was associated with an increased risk of serious cardiovascular events, although the upper limit of the 95% confidence interval indicated that a doubling of the risk could not be ruled out. However, the absolute magnitude of such an increased risk would be low. (Funded by the Agency for Healthcare Research and Quality and the Food and Drug Administration.).

Cardiovascular risk of stimulant treatment in pediatric attention-deficit/hyperactivity disorder: update and clinical recommendations

OBJECTIVE

This review provides an update on the cardiovascular impact of therapeutic stimulant-class medication for children and adolescents with attention-deficit/hyperactivity disorder (ADHD).

METHOD

Relevant clinical literature was ascertained using PubMed searches limited to human studies and the English language as of May 2011. Current practice guidelines and consensus statements also were reviewed.

RESULTS

Stimulant-class medications for healthy children and adolescents with ADHD are associated with mean elevations in blood pressure (≤5 mmHg) and heart rate (≤10 beats/min) without changes in electrocardiographic parameters. A subset (5-15%) of children and adolescents treated may have a greater increase in heart rate or blood pressure at a given assessment or may report a cardiovascular-type complaint during stimulant treatment. It is extremely rare for a child or adolescent receiving stimulant medication to have a serious cardiovascular event during treatment, with the risk appearing similar to groups of children not receiving stimulant medication.

CONCLUSIONS

Clinicians should adhere to current recommendations regarding the prescription of stimulant medications for youth with ADHD. Scientific inquiry is indicated to identify patients at heightened risk and to continue surveillance for the longer-term cardiovascular impact of these agents.

Adult attention-deficit/hyperactivity disorder treatment and cardiovascular implications

Attention-deficit/hyperactivity disorder (ADHD) is a chronic neurobehavioral disorder afflicting adults worldwide. This article is an update on the evidence supporting medications for adult ADHD, with particular emphasis on cardiovascular implications. Relevant clinical literature was sought using PubMed searches, with an emphasis on new reports from April 2009 to April 2011. This review describes the efficacy and general tolerability of stimulant and nonstimulant medications for adults with ADHD as seen in contemporary clinical trials. Cardiovascular response to medications for ADHD is primarily seen in heart rate and blood pressure elevations, while less is known about the etiology of rare cardiovascular events or long-term sequelae. Further research is indicated to delineate clinical and functional outcomes for adults with ADHD, as well as long-term safety of medication treatment.

Attention deficit hyperactivity disorder and the athlete: an American Medical Society for Sports Medicine position statement

Attention deficit hyperactivity disorder (ADHD) is an important issue for the physician taking care of athletes since ADHD is common in the athletic population, and comorbid issues affect athletes of all ages. The health care provider taking care of athletes should be familiar with making the diagnosis of ADHD, the management of ADHD, and how treatment medications impact exercise and performance. In this statement, the term "Team Physician" is used in reference to all healthcare providers that take care of athletes. These providers should understand the side effects of medications, regulatory issues regarding stimulant medications, and indications for additional testing. This position statement is not intended to be a comprehensive review of ADHD, but rather a directed review of the core issues related to the athlete with ADHD.

To stop or not to stop? How long should medication treatment of attention-deficit hyperactivity disorder be extended?

ADHD is a common neuropsychiatric disorder with a strong persistence over time. Medication is frequently used in the clinical management of ADHD. After response, medication is typically prescribed for months to years. It is unclear whether extended medication treatment provides long-term benefits and how long it should be continued. Furthermore, there is concern about the long-term safety of ADHD medication. The aim of this systematic review is to address these issues and provide recommendations about the decision to stop or not to stop ADHD medication. We performed a search in PubMed and focused on medication studies with a treatment longer than 12weeks in subjects 6-18years old. Extended placebo-controlled double-blind parallel studies are not available. Placebo-controlled discontinuation studies and prospective long-term observational treatment studies provide evidence that medication management leads to a substantial reduction of ADHD symptoms and less impairment of functioning for a period of about 2years. There is limited and inconsistent evidence for long-term advantage of medication treatment beyond symptom control, such as improved social functioning, academic achievement, employment status and less adverse psychiatric outcome. In terms of safety, long-term effects of medication on growth, blood pressure and heart rate are limited and the occurrence of suicidal, psychotic and manic symptoms is rare. Animal data about neurotoxic effects of psycho stimulants cannot be directly extrapolated to humans. Therefore, clinical decisions about starting, continuing, and stopping of ADHD medication should be made on an individual basis. Medication free periods should be implemented at regular times to investigate the need for an ongoing benefit of medication. Unfounded assumptions about continuing benefit of medication use should be abandoned. Careful monitoring of side effects is necessary and must be able to detect early alarming signals.

Advances in understanding and treating ADHD

Attention deficit hyperactivity disorder (ADHD) is a neurocognitive behavioral developmental disorder most commonly seen in childhood and adolescence, which often extends to the adult years. Relative to a decade ago, there has been extensive research into understanding the factors underlying ADHD, leading to far more treatment options available for both adolescents and adults with this disorder. Novel stimulant formulations have made it possible to tailor treatment to the duration of efficacy required by patients, and to help mitigate the potential for abuse, misuse and diversion. Several new non-stimulant options have also emerged in the past few years. Among these, cognitive behavioral interventions have proven popular in the treatment of adult ADHD, especially within the adult population who cannot or will not use medications, along with the many medication-treated patients who continue to show residual disability.

European guidelines on managing adverse effects of medication for ADHD

The safety of ADHD medications is not fully known. Concerns have arisen about both a lack of contemporary-standard information about medications first licensed several decades ago, and signals of possible harm arising from more recently developed medications. These relate to both relatively minor adverse effects and extremely serious issues such as sudden cardiac death and suicidality. A guidelines group of the European Network for Hyperkinetic Disorders (EUNETHYDIS) has therefore reviewed the literature, recruited renowned clinical subspecialists and consulted as a group to examine these concerns. Some of the effects examined appeared to be minimal in impact or difficult to distinguish from risk to untreated populations. However, several areas require further study to allow a more precise understanding of these risks.

Cardiovascular effects of medications for the treatment of attention-deficit hyperactivity disorder: what is known and how should it influence prescribing in children?

The effective medications currently marketed for attention-deficit hyperactivity disorder (ADHD) have central and peripheral catecholaminergic effects that have been shown to result in statistically significant increases in heart rate and blood pressure. The impact of these medications on serious cardiovascular events in healthy children is unknown, but serious cardiovascular events related to ADHD medications are considered rare. However, children with cardiac pathology may be at greater risk given that increased sympathetic tone has been reported as a causal factor in generating ventricular arrhythmias in adults with coronary artery disease, and physical exercise has been consistently reported as a trigger for increased risk of sudden cardiac death in athletes with underlying cardiovascular disease. ADHD has high co-morbidity with anxiety and depression. These conditions in adults have been reported to have their own cardiovascular risks that may be compounded by interactions resulting from combined pharmacotherapeutic treatments; this interaction has not been evaluated in children. High rates of ADHD reported in subjects with cardiac pathology, as well as in patients with genetic disorders associated with cardiovascular pathology, also suggest that the prevalence of cardiac pathology in ADHD subjects may be greater than that in the general population. Currently, the US FDA and Health Canada require warnings on prescription labeling information for ADHD medications, suggesting that these medications should not generally be used in children or adults with 'known' serious cardiac pathology. Family history, medical history, and physical examination have very low sensitivity for identifying serious cardiac pathology, but this can be markedly enhanced in many instances with the use of electrocardiography, which has high specificity and sensitivity. Identifying and managing underlying cardiovascular pathology may not eliminate the risk of serious cardiovascular events but may increase the safety of using medication frequently required for effective management of ADHD. When the very common and serious consequences from untreated ADHD are also considered in the assessment of risks and benefits, even in the presence of cardiac pathology, it seems that the prescribing of ADHD medications in children should remain unchanged.