Combination use of atomoxetine hydrochloride and olanzapine in the treatment of attention-deficit/hyperactivity disorder with comorbid disruptive behavior disorder in children and adolescents 10-18 years of age

Contemporary diagnosis and treatment of conduct disorder in youth

INTRODUCTION

Conduct disorder (CD) is characterized by repetitive and persistent antisocial behaviors, being among the most frequently reported reasons of referral in youth. CD is a highly heterogeneous disorder, with possible specifiers defined according to age at onset, Limited Prosocial Emotions (LPE) otherwise known as Callous-Unemotional (CU) traits, Emotional Dysregulation (ED), and patterns of comorbidity, each with its own specific developmental trajectories.

AREAS COVERED

The authors review the evidence from published literature on the clinical presentations, diagnostic procedures, psychotherapeutic and psychoeducational approaches, and pharmacological interventions from RCT and naturalistic studies in youth. Evidence from studies including youths with LPE/CU traits, ED and aggression are also reviewed, as response moderators.

EXPERT OPINION

Due to its clinical heterogeneity, relevant subtypes of CD should be carefully characterized to gain reliable information on prognosis and treatments. Thus, disentangling this broad category in subtypes is crucial as a first step in diagnosis. Psychosocial interventions are the first option, possibly improving LPE/CU traits and ED, especially if implemented early during development. Instead, limited information, based on low-quality studies, supports pharmacological options. Second-generation antipsychotics, mood stabilizers, and stimulants are first-line medications, according to different target symptoms, such as aggression and emotional reactivity. Developmental pathways including ADHD suggest a specific role of psychostimulants.

Psychopharmacology of Treating Explosive Behavior

Explosive and aggressive behavior in children can pose safety risks, disturb family functioning, and lead to significant impairments. Pharmacologic management should be based on the first-line treatment of the primary psychiatric diagnoses of the patient and initiated in combination with appropriate psychosocial interventions. Review of the literature suggests that risperidone has the most supporting evidence in the treatment of explosive behavior. Stimulants have been shown to be helpful in the treatment of explosive behavior in attention-deficit/hyperactivity disorder. Medication treatment can be associated with significant side effects and therefore the risks and benefits of medication management must be weighed carefully.

Polypharmacy in the Management of Attention-Deficit/Hyperactivity Disorder in Children and Adolescents: A Review and Update

Objective: Prescription of multiple medications concurrently for children and adolescents has increased in recent years. Examination of this practice has been undervalued relative to its incidence. This article reviews studies investigating effectiveness of medication combinations for youth with attention-deficit/hyperactivity disorder (ADHD). Methods: A literature search identified studies that combined two or more prescribed medications for the treatment of ADHD. Included studies focused on youth; had study design of randomized controlled trial (RCT), nonrandomized trial, or case review (n > 10); and included an outcome measure of treatment effectiveness. Results: Thirty-nine pertinent studies were identified. All studies combined two medications, with the vast majority including a stimulant (n = 37). The largest group (n = 16) combined stimulant and alpha-agonist, finding greater efficacy than alpha-agonist alone but not stimulant alone in all cases. A few RCTs found benefit from the addition of risperidone or divalproex to stimulant for comorbid aggression. Four studies adding atomoxetine found mixed reports of benefit, including the only small RCT showing no benefit. RCTs with selective serotonin reuptake inhibitors found minimal evidence of benefit for mood or anxiety comorbidities. Conclusion: The best studied combination is stimulant and alpha-agonist; addition of alpha-agonist to stimulant seems effective for residual symptoms of ADHD. Stimulant plus risperidone has the most evidence of efficacy for comorbid aggression or disruptive behavior. Limited support exists for the effectiveness of other medication combinations, including no trials studying three or more medications concurrently. Combinations frequently yielded more side effects, leaving monotherapy preferable if a sufficient treatment response can be achieved.

Population pharmacokinetics of olanzapine in children

AIMS

The aim of this study was to evaluate the population pharmacokinetics (PopPK) of olanzapine in children and devise a model-informed paediatric dosing scheme.

METHODS

The PopPK of olanzapine was characterized using opportunistically collected plasma samples from children receiving olanzapine per standard of care for any indication. A nonlinear mixed effect modelling approach was employed for model development using the software NONMEM (v7.4). Simulations from the developed PopPK model were used to devise a paediatric dosing scheme that targeted comparable plasma exposures to adolescents and adults.

RESULTS

Forty-five participants contributed 83 plasma samples towards the analysis. The median (range) postnatal age and body weight of participants were 3.8 years (0.2-19.2) and 14.1 kg (4.2-111.7), respectively. The analysis was restricted to pharmacokinetic (PK) samples collected following enteral administration (oral and feeding tube). A one-compartment model with linear elimination provided an appropriate fit to the data. The final model included the covariates body weight and postmenstrual age (PMA) on apparent olanzapine clearance (CL/F). Typical CL/F and apparent volume of distribution (scaled to 70 kg) were 16.8 L/h (21% RSE) and 663 L (13% RSE), respectively. Developed dosing schemes used weight-normalized doses for children ≤6 months postnatal age or <15 kg and fixed doses for children ≥15 kg.

CONCLUSION

We developed a paediatric PopPK model for enterally-administered olanzapine. To our knowledge, this analysis is the first study to characterize the PK of olanzapine in participants ranging from infants to adolescents. Body weight and PMA were identified as influential covariates for characterizing developmental changes in olanzapine apparent clearance.

Noradrenergic Source of Dopamine Assessed by Microdialysis in the Medial Prefrontal Cortex

Previous results indicate that dopamine (DA) release in the medial prefrontal cortex (mPFC) is modified by α₂ adrenoceptor- but not D2 DA receptor- agonists and antagonists, suggesting that DA measured by microdialysis in the mPFC originates from noradrenergic terminals. Accordingly, noradrenergic denervation was found to prevent α₂-receptor-mediated rise and fall of extracellular DA induced by atipamezole and clonidine, respectively, in the mPFC. The present study was aimed to determine whether DA released by dopaminergic terminals in the mPFC is not detected by in vivo microdialysis because is readily taken up by norepinephrine transporter (NET). Accordingly, the D2-antagonist raclopride increased the electrical activity of DA neurons in the ventral tegmental area (VTA) and enhanced extracellular DOPAC but failed to modify DA in the mPFC. However, in rats whose NET was either inactivated by nisoxetine or eliminated by noradrenergic denervation, raclopride still elevated extracellular DOPAC and activated dopaminergic activity, but also increased DA. Conversely, the D2-receptor agonist quinpirole reduced DOPAC but failed to modify DA in the mPFC in control rats. However, in rats whose NET was eliminated by noradrenergic denervation or inhibited by locally perfused nisoxetine, quinpirole maintained its ability to reduce DOPAC but acquired that of reducing DA. Moreover, raclopride and quinpirole, when locally perfused into the mPFC of rats subjected to noradrenergic denervation, were able to increase and decrease, respectively, extracellular DA levels, while being ineffective in control rats. Transient inactivation of noradrenergic neurons by clonidine infusion into the locus coeruleus, a condition where NET is preserved, was found to reduce extracellular NE and DA in the mPFC, whereas noradrenergic denervation, a condition where NET is eliminated, almost totally depleted extracellular NE but increased DA. Both transient inactivation and denervation of noradrenergic neurons were found to reduce the number of spontaneously active DA neurons and their bursting activity in the VTA. The results indicate that DA released in the mPFC by dopaminergic terminals is not detected by microdialysis unless DA clearance from extracellular space is inactivated. They support the hypothesis that noradrenergic terminals are the main source of DA measured by microdialysis in the mPFC during physiologically relevant activities.

Methylphenidate Dose-Dependently Affects Aggression and Improves Fear Extinction and Anxiety in BALB/cJ Mice

Overt aggression, increased anxiety, and dysfunctional fear processing are often observed in individuals with conduct disorder (CD) and attention-deficit hyperactivity disorder (ADHD). Methylphenidate (MPH), a psychostimulant increasing dopamine and noradrenaline tone, is effective in reducing aggression in both CD and ADHD individuals. However, it is unclear to which extent these effects of MPH are dose dependent. Here, the effects of acute intraperitoneal MPH (3 and 10 mg/kg) on aggression, anxiety, social behavior, and fear extinction were investigated in BALB/cJ mice. Previous studies in BALB/cJ mice have revealed high levels of aggression and anxiety that are associated with reduced top-down cortical control. Administration of 3 mg/kg MPH prolonged the attack latency and prevented escalation of aggression over time compared to vehicle-treated mice, while 10 mg/kg MPH increased number of bites and attacks. In addition, 3 mg/kg MPH decreased social interaction slightly. A strong anxiolytic effect was found after administration of both the 3 and 10 mg/kg doses in the elevated plus maze and the open-field test. In addition, while vehicle-treated BALB/cJ animals showed intact freezing, both doses of MPH decreased freezing to the unconditioned stimulus in a fear-conditioning paradigm. A long-lasting effect on fear extinction was visible after treatment with the 10 mg/kg dose. The data support a role for MPH in the regulation of anxiety, fear processing, and aggression in BALB/cJ mice, with the latter effect in a dose-dependent manner. The findings provide a further context for examining the effects of MPH in clinical disorders such as ADHD and CD.

Atypical antipsychotics for disruptive behaviour disorders in children and youths

BACKGROUND

This is an update of the original Cochrane Review, last published in 2012 (Loy 2012). Children and youths with disruptive behaviour disorders may present to health services, where they may be treated with atypical antipsychotics. There is increasing usage of atypical antipsychotics in the treatment of disruptive behaviour disorders.

OBJECTIVES

To evaluate the effect and safety of atypical antipsychotics, compared to placebo, for treating disruptive behaviour disorders in children and youths. The aim was to evaluate each drug separately rather than the class effect, on the grounds that each atypical antipsychotic has different pharmacologic binding profile (Stahl 2013) and that this is clinically more useful.

SEARCH METHODS

In January 2017, we searched CENTRAL, MEDLINE, Embase, five other databases and two trials registers.

SELECTION CRITERIA

Randomised controlled trials of atypical antipsychotics versus placebo in children and youths aged up to and including 18 years, with a diagnosis of disruptive behaviour disorders, including comorbid ADHD. The primary outcomes were aggression, conduct problems and adverse events (i.e. weight gain/changes and metabolic parameters). The secondary outcomes were general functioning, noncompliance, other adverse events, social functioning, family functioning, parent satisfaction and school functioning.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Two review authors (JL and KS) independently collected, evaluated and extracted data. We used the GRADE approach to assess the quality of the evidence. We performed meta-analyses for each of our primary outcomes, except for metabolic parameters, due to inadequate outcome data.

MAIN RESULTS

We included 10 trials (spanning 2000 to 2014), involving a total of 896 children and youths aged five to 18 years. Bar two trials, all came from an outpatient setting. Eight trials assessed risperidone, one assessed quetiapine and one assessed ziprasidone. Nine trials assessed acute efficacy (over four to 10 weeks); one of which combined treatment with stimulant medication and parent training. One trial was a six-month maintenance trial assessing symptom recurrence.The quality of the evidence ranged from low to moderate. Nine studies had some degree of pharmaceutical support/funding. Primary outcomesUsing the mean difference (MD), we combined data from three studies (238 participants) in a meta-analysis of aggression, as assessed using the Aberrant Behaviour Checklist (ABC) ‒ Irritability subscale. We found that youths treated with risperidone show reduced aggression compared to youths treated with placebo (MD -6.49, 95% confidence interval (CI) -8.79 to -4.19; low-quality evidence). Using the standardised mean difference (SMD), we pooled data from two risperidone trials (190 participants), which used different scales: the Overt Aggression Scale ‒ Modified (OAS-M) Scale and the Antisocial Behaviour Scale (ABS); as the ABS had two subscales that could not be combined (reactive and proactive aggression), we performed two separate analyses. When we combined the ABS Reactive subscale and the OAS-M, the SMD was -1.30 in favour of risperidone (95% CI -2.21 to -0.40, moderate-quality evidence). When we combined the ABS Proactive subscale and OAS-M, the SMD was -1.12 (95% CI -2.30 to 0.06, moderate-quality evidence), suggesting uncertainty about the estimate of effect, as the confidence intervals overlapped the null value. In summary, there was some evidence that aggression could be reduced by risperidone. Data were lacking on other atypical antipsychotics, like quetiapine and ziprasidone, with regard to their effects on aggression.We pooled data from two risperidone trials (225 participants) in a meta-analysis of conduct problems, as assessed using the Nisonger Child Behaviour Rating Form ‒ Conduct Problem subscale (NCBRF-CP). This yielded a final mean score that was 8.61 points lower in the risperidone group compared to the placebo group (95% CI -11.49 to -5.74; moderate-quality evidence).We investigated the effect on weight by performing two meta-analyses. We wanted to distinguish between the effects of antipsychotic medication only and the combined effect with stimulants, since the latter can have a counteracting effect on weight gain due to appetite suppression. Pooling two trials with risperidone only (138 participants), we found that participants on risperidone gained 2.37 kilograms (kg) more (95% CI 0.26 to 4.49; moderate-quality evidence) than those on placebo. When we added a trial where all participants received a combination of risperidone and stimulants, we found that those on the combined treatment gained 2.14 kg more (95% CI 1.04 to 3.23; 3 studies; 305 participants; low-quality evidence) than those on placebo. Secondary outcomesOut of the 10 included trials, three examined general functioning, social functioning and parent satisfaction. No trials examined family or school functioning. Data on non-compliance/attrition rate and other adverse events were available from all 10 trials.

AUTHORS' CONCLUSIONS

There is some evidence that in the short term risperidone may reduce aggression and conduct problems in children and youths with disruptive behaviour disorders There is also evidence that this intervention is associated with significant weight gain.For aggression, the difference in scores of 6.49 points on the ABC ‒ Irritability subscale (range 0 to 45) may be clinically significant. It is challenging to interpret the clinical significance of the differential findings on two different ABS subscales as it may be difficult to distinguish between reactive and proactive aggression in clinical practice. For conduct problems, the difference in scores of 8.61 points on the NCBRF-CP (range 0 to 48) is likely to be clinically significant. Weight gain remains a concern.Caution is required in interpreting the results due to the limitations of current evidence and the small number of high-quality trials. There is a lack of evidence to support the use of quetiapine, ziprasidone or any other atypical antipsychotic for disruptive behaviour disorders in children and youths and no evidence for children under five years of age. It is uncertain to what degree the efficacy found in clinical trials will translate into real-life clinical practice. Given the effectiveness of parent-training interventions in the management of these disorders, and the somewhat equivocal evidence on the efficacy of medication, it is important not to use medication alone. This is consistent with current clinical guidelines.

The pharmacological treatment of aggression in children and adolescents with conduct disorder. Do callous-unemotional traits modulate the efficacy of medication?

BACKGROUND

Children and adolescents with conduct disorder (CD) show repetitive and persistent patterns of aggressive behaviour and the more severe forms are often associated with callous-unemotional (CU) traits.

OBJECTIVES

To systematically review and, where data are adequate, conduct meta-analyses on the efficacy of medication on aggression in children and adolescent with CD considering the impact of CU traits.

RESULTS

Few studies have investigated patients with CD as primary diagnosis, and few of these have discriminated between different types of aggression or reported measures of CU traits. Methylphenidate and risperidone showed the largest effects on aggression in randomized controlled trials; other antipsychotics showed clinical efficacy on CD but this evidence is mainly revealed by open label trials. There is some low quality evidence to support a small effect of mood stabilizers and other agents. There were only two papers describing the effects of CU traits thus providing inconclusive results.

CONCLUSION

Considering heterogeneity of the disorder, more proof-of-concept clinical studies are needed to define effects of medication and role of CU traits.

Efficacy of atomoxetine in the treatment of attention-deficit hyperactivity disorder in patients with common comorbidities in children, adolescents and adults: a review

Attention-deficit hyperactivity disorder (ADHD) is one of the most commonly diagnosed mental health disorders and is associated with higher incidence of comorbid oppositional or conduct, mood, anxiety, pervasive developmental, and substance-use disorders. Comorbid mental health conditions may alter the presence of symptoms and treatment of ADHD. Atomoxetine (ATX), a nonstimulant medication for the treatment of ADHD, may be prescribed for individuals with ADHD and comorbid conditions despite some risk for certain undesirable side effects and lower effectiveness for the treatment of ADHD than stimulants. In this paper, we review studies utilizing randomized, placebo-controlled trials (RCTs) as well as within-subject designs to determine the effectiveness of ATX in the treatment of children and adults with ADHD and comorbid conditions. The current review uses an expanded methodology beyond systematic review of randomized controlled trials in order to improve generalizability of results to real-world practice. A total of 24 articles published from 2007 to 2015 were reviewed, including 14 RCTs: n = 1348 ATX, and n = 832 placebo. The majority of studies show that ATX is effective in the treatment of ADHD symptoms for individuals with ADHD and comorbid disorders. Cohen's d effect sizes (ES) for improvement in ADHD symptoms and behaviors range from 0.47 to 2.21. The effectiveness of ATX to improve symptoms specific to comorbidity varied by type but appeared to be most effective for diminishing the presence of symptoms for those with comorbid anxiety, ES range of 0.40 to 1.51, and oppositional defiant disorder, ES range of 0.52 to 1.10. There are mixed or limited results for individuals with ADHD and comorbid substance-use disorders, autism spectrum disorders, dyslexia or reading disorder, depression, bipolar disorder, and Tourette syndrome. Results from this review suggest that ATX is effective in the treatment of some youth and adults with ADHD and comorbid disorders, and may be a treatment option in these patients.

Effects of the combination of wheel running and atomoxetine on cue- and cocaine-primed reinstatement in rats selected for high or low impulsivity

BACKGROUND

Aerobic exercise and the attention-deficit/hyperactivity disorder medication, atomoxetine (ATO), are two monotherapies that have been shown to suppress reinstatement of cocaine-seeking in an animal model of relapse. The present study investigated the effects of combining wheel running and ATO versus each treatment alone on cocaine-seeking precipitated by cocaine and cocaine-paired cues in rats with differing susceptibility to drug abuse (i.e., high vs. low impulsive).

METHODS

Rats were screened for high (HiI) or low impulsivity (LoI) based on their performance on a delay-discounting task and then trained to self-administer cocaine (0.4 mg/kg/inf) for 10 days. Following 14 days of extinction, both groups were tested for reinstatement of cocaine-seeking precipitated by cocaine or cocaine-paired cues in the presence of concurrent running wheel access (W), pretreatment with ATO, or both (W+ATO).

RESULTS

HiI rats acquired cocaine self-administration more quickly than LoI rats. While both individual treatments and W+ATO significantly attenuated cue-induced cocaine seeking in HiI and LoI rats, only W+ATO was effective in reducing cocaine-induced reinstatement compared with vehicle treatment. There were dose-dependent and phenotype-specific effects of ATO with HiI rats responsive to the low but not high ATO dose. Floor effects of ATO and W on cue-induced reinstatement prevented the assessment of combined treatment effects.

CONCLUSIONS

These findings demonstrated greater attenuation of cue- versus cocaine-induced reinstatement by ATO and W alone and recapitulate impulsivity phenotype differences in both acquisition of cocaine self-administration and receptivity to treatment.