Counseling Points - January 2009 - (Page 6)

Thus, dextroamphetamine-containing agents should not be used in patients with a history of structural/congenital heart defects.The American Academy of Pediatrics (AAP) recommends that a history of cardiac disease be taken and a cardiac examination performed when stimulants are being considered as a course of therapy for ADHD.16 Nonstimulants Atomoxetine. Unlike methylphenidate and dextroamphetamine, atomoxetine (Strattera®) mainly blocks the reuptake of norepinephr ine into the presynaptic neuron.8 In a randomized, open-label trial, atomoxetine improved the core symptoms of ADHD similar to methylphenidate.17 Individuals weighing ≤70 kg should be started on 0.5 mg/kg/day orally (divided once or twice daily) and titrated to 1.2 mg/kg/day after 3 to 5 days. Those weighing >70 kg should be started on 40 mg/day orally and titrated to 80 mg/day after 3-5 days. If a positive response is not reached, the dose should be titrated accordingly up to 100 mg/day for individuals weighing >70 kg, and a maximum of 1.4 mg/kg/day for those weighing <70 kg.8 Atomoxetine causes adverse effects similar to those produced by methylphenidate.17 It has been shown not to exacerbate tic disorder, but may cause severe hepatotoxicity.18,19 It may also increase the risk of suicidal thoughts in young individuals.20 These proposed risks should be discussed with caregivers. Clinicians should monitor children and adolescents with ADHD closely after starting atomoxetine. Tricyclic Antidepressants (TCAs) and Bupropion. Neither TCAs (e.g., imipramine [Tofranil ® ] and desipramine [Norpramin®]) nor bupropion (Wellbutrin®) are approved by the Food and Drug Administration (FDA) for ADHD management, but both are prescribed for the disorder. TCAs are efficacious in controlling behavior problems and cognitive impairment, and bupropion is mainly used as an adjunct therapy in patients with co-morbid depression.21 Both types of agents block the reuptake of norepinephrine and serotonin into the presynaptic neuron, but bupropion also inhibits neuronal reuptake of dopamine.8 Most TCAs are inexpensive, and do not cause rebound effects or insomnia. However, anticholinergic side effects (e.g., sedation, dry month, and constipation) and potentially serious cardiovascular problems (i.e. arrhythmia) have been reported. Bupropion can lower the seizure threshold, and is contraindicated in individuals with a history of seizures. Bupropion can also cause insomnia, agitation, and anxiety, and should be avoided in children and adolescents with co-morbid anxiety disorder.22 Clonidine. Clonidine (Catapres®) is not FDA approved for ADHD management, but it is the drug of choice in COUNSELING POINTS™ 6 children and adolescents with co-morbid tic disorder.19 It is commonly used to reduce the severity of tics and to relieve insomnia.4 Clonidine is available in tablet and transdermal formulations. If the transdermal patch is used, clinical experience suggests that it may need to be changed every 5 days rather than the every-7-day dosing required for medical conditions such as hypertension. Sedation is the most common side effect of clonidine, along with dry mouth, headache, and a reduction in blood pressure.8 Rebound hypertension can occur with abrupt withdrawal, so a tapered withdrawal is recommended.8 Treatment Strategies When starting children and adolescents on stimulants, clinicians should choose the lowest dose possible to avoid unwanted side effects.1 Unlike other medications used in pediatrics, doses of both methylphenidate and dextroamphetamine are not based on the individual’s weight.4 The selection of which agent to use depends on the clinician’s preference and the desired duration of effect (short-acting versus long-acting). No studies thus far have shown superiority of one agent over another (methylphenidate versus dextroamphetamine).4 In fact, when one stimulant is ineffective, another stimulant should be tried before switching to a new class of medication. According to Greenhill and colleagues, core ADHD symptoms improve equally well in response to both methylphenidate and amphetamine for 38% of children, while 62% experience improvements in response to one stimulant but not the other.23 If the child/adolescent has tried two stimulants and still has not achieved an adequate clinical response, the clinician should prescribe a nonstimulant.4 AAP guidelines only recommend TCAs and bupropion, but recent data have also shown efficacy with atomoxetine monotherapy.4,24 Bupropion and atomoxetine are better options if 24-hour symptom relief is required. Clonidine may be used as an alternative agent, especially when a reduction in the severity of tics or insomnia relief is desired.4 When a child/adolescent is on a stable and effective dose of ADHD medication, controversy exists regarding the practice of drug holidays (e.g., stopping medication during the summer when school is out) to reduce the risks of side effects. Long-term benefits of drug holidays have not been established, but the Multimodal Treatment Study of ADHD (MTA) demonstrated that the benefits of ADHD medication therapy diminish over time after discontinuation of 14 months of intensive therapy.6 After an individual is started on ADHD medication, follow-up visits should initially be conducted every month to assess response.6 Medication should be titrated to effect every 3-7 days depending on adverse effects and the individual’s tolerance.4,25 Once the dose is stabilized, clinic visits can be extended to every 3-4 months.6

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Counseling Points - January 2009

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