Pocket Guide For The Textbook Of Pharmacotherapy For Child And Adolescent psychiatric disorders

David Rosenberg

• Publisher: Routledge
• Year: 2013
• Edition: 1
• eBook ISBN:
  9781134860098
• Topic: Medicine
• Subtopic: Psychiatry & Mental Health

This is a quick-reference guide for psychiatrists, therapists, social workers, and other practitioners about each group of medications. This guide, which discusses the use of psychiatric drugs in patients under 18, accompanies the author team's complete book Textbook of Pharmacotherapy for Child and Adolescent Psychiatric Disorders.; Clinical indications, dosage guidelines, side-effects, common drug interactions and most tables are retained and updated in this guide. the guide provides the reader with the practical guidelines to safely and effectively prescribe medication.

S e c t i o n I I

Classes of Medication

C h a p t e r 3

Psychostimulants

The psychostimulants methylphenidate (Ritalin), dextroamphetamine sulfate (Dexedrine), and magnesium pemoline (Cylert) are the most commonly prescribed medications in all of child psychiatry, despite the fact that they have been approved by the Food and Drug Administration (FDA) only for attention-deficit hyperactivity disorder (ADHD) in children, adolescents, and adults, and for narcolepsy.^7,12,21 Nearly 2% of the school-age population receive stimulant medication for ADHD symptoms.⁷ These medications remain controversial, however, because of their side effects and concern about their potential for abuse and addiction, leading certain special-interest groups to press for their immediate recall and removal from the market.

Currently, methylphenidate and dextroamphetamine sulfate are classified by the FDA as Schedule II drugs, the most restrictive classification for drugs felt to be medically useful.^15,21 Magnesium pemoline is classified as a Schedule IV drug. The authors wish to emphasize, however, that in the field of child psychiatry, and in psychiatry in general, the use of stimulant medications is not considered controversial. These medications are solid, first-line, bread-and-butter–type medications with a remarkably benign side-effect profile. The disorder that they are most commonly used to treat, ADHD, is one with marked functional impairment, long-term morbidity, and enormous consequences for the child and family. Although more long-term studies are needed, the drugs have demonstrated efficacy (see below). It is true that children and adolescents with ADHD exhibit a twofold to fourfold increased risk for substance abuse, but current data show no evidence that the use of prescribed stimulant medication results in the increased use, or abuse of, and dependence on, recreational or prescription drugs, or in dependence on and addiction to the stimulants themselves.^7,12,43 Nonetheless, close supervision and monitoring of the child or adolescent and his or her family members for the potential for abuse are required when stimulants are prescribed. When used properly, the stimulants are beneficial and safe, as well as cost-effective, in decreasing hyperactivity, distractibility, impulsivity, and fidgetiness, and in increasing attention span. State-dependent learning is not a problem when stimulants are used.⁷ Cognitive effects may respond optimally to relatively modest doses of stimulant medications, while behavioral symptoms may require larger doses.^23-25 No normative clinical or laboratory values have been elucidated at this time.

Carlson and associates⁴⁸ compared the effects of methylphenidate with those of placebo on the performance of ADHD boys following their success or failure at tasks assigned to them. They provided evidence for a “salutary” effect of methylphenidate on the boys’ performance and perceptions after attempting to solve both solvable and unsolvable puzzles. Boys exposed to un-solvable puzzles demonstrated increased persistence on a subsequent generalization task when receiving methylphenidate as compared with placebo. No differences were found between placebo and a “no pill” condition on the Posner letter-matching task and four other measures of phonologic processing in an attempt to isolate the effects of methylphenidate to parameter estimates of selective attention, the basic cognitive process of retrieving name codes from permanent memory, and a constant term that represented nonspecific aspects of information processing. Responses to the letter-matching stimuli were found to be more rapid with methylphenidate than with placebo.⁴⁹ It is important to note that this improvement in performance was isolated to the parameter estimate that reflected nonspecific aspects of information processing.

A lack of active medication effect was found on the other measures of phonologic processing, supporting the Posner task finding suggesting that methylphenidate exerts beneficial effects on academic processing through general rather than specific aspects of information processing.⁴⁹

Chemical Properties

For the chemical properties of the psychostimulants, see Table 3-1 and Figures 3-1 through 3-3.

Table 3-1
Pharmacokinetics of CNS Stimulants in Children and Adolescents

Figure 3-1
Methylphenidate (Ritalin)

The stimulants used in child and adolescent psychiatry are sympathomimetic amines that may be administered orally.^7,12,15,21 They are then absorbed from the GI tract, and cross the blood–brain barrier. The onset of action for methylphenidate and dextroamphetamine is generally observed within 20 minutes to one hour, with a three- to six-hour duration of action.^7,12 Stimulants of the central nervous system (CNS) exert their maximum effect when they are being most rapidly absorbed, and clinical efficacy is probably related to the rate of rise of the blood level.¹² This is when the

Figure 3-2
Amphetamine

Figure 3-3
Pemoline

target symptoms, including hyperactivity, distractibility, inattentiveness, impulsivity, and fidgetiness, are most susceptible to the stimulants’ effects. The clinical effectiveness of the stimulants has not been shown to correlate with absolute or peak blood levels,¹² and no therapeutic window has as yet been delineated for any of them.^7,12 Sustained-release methylphenidate’s onset of action can be delayed for as long as three hours, with a shorter overall duration of action and more day-to-day variability than two doses of regular methylphenidate given around breakfast and lunchtime.^27,28

Pelham and associates²⁷ compared the relative efficacy of standard methylphenidate, sustained-release methylphenidate, sustained-release dextroamphetamine, and pemoline in 22 ADHD children in a double-blind, placebo-controlled crossover evaluation. They found that sustained-release dextroamphetamine and pemoline produced the most consistent beneficial effects and were recommended for 10 of the 15 children who were responders to medication. The continuous-performance task results demonstrated that all four medications had an effect within two hours of ingestion, and the effects lasted for nine hours.²⁸

Indications

Indications for use are shown in Table 3-2.

ADHD Children and Adolescents

Over 600,000 children per year are treated with stimulants for ADHD symptoms.⁷ ADHD which is most often considered a disorder of catecholamine underactivity.

Table 3-2
Indications for CNS Stimulants in Childhood and Adolescent Psychiatry

FDA-approved indications ADHD in childhood and adolescence Narcolepsy (methylphenidate and dextroamphetamine) Exogenous obesity (dextroamphetamine)

Possible indications ADHD in preschool children Undifferentiated attention-deficit disorder ADHD in intellectually subaverage children and adolescents ADHD symptoms in children and adolescents with Fragile X syndrome ADHD symptoms in children and adolescents with PDD (autism) ADHD symptoms in children and adolescents with head trauma and/or organic brain disease ADHD in children and/or adolescents with tic disorders (i.e., Tourette’s syndrome) Potentiation of narcotic analgesia

The therapeutic effect of stimulants, sympathomimetic agents that increase catecholamine levels by inhibiting their reuptake, provides indirect evidence for this concept. Up until recently, stimulant medications were predominantly prescribed to children 6 to 10 years of age, and generally were discontinued around the onset of puberty and adolescence. Many practicing clinicians believed that ADHD remitted at puberty, but further investigation has demonstrated that its course is extremely variable, and that symptoms can and do persist into adolescence and adulthood.^9,32 Stimulants have been found effective in treating ADHD symptoms throughout life,^32,50,51 which has led to a dramatic increase in their use for both adolescents and adults. Approximately one million persons with ADHD have been treated with stimulants thus far;^7,32 nonetheless, they frequently are not prescribed correctly.

Case History

A 10-year-old boy was referred for child psychiatric evaluation because of “problem school behavior.” He was found to have a history of disruptive behavior since the age of 2, and, according to his mother, had since become more “hyper.” She and her husband had hoped that the child would “grow out of it,” but instead his behavior deteriorated. He was failing all of his fifth-grade courses, despite school psychoeducational assessment that revealed that he functioned in the above-average range. The school was threatening to expel him for his disruptive behavior, which included an inabi...

Table of contents

• Cover
• Half Title
• Full Title
• Copyright
• Contents
• Foreword
• Preface
• SECTION I. INTRODUCTION TO PSYCHOPHARMACOLOGY
• SECTION II. CLASSES OF MEDICATION
• Appendix
• Name Index
• Subject Index
• About the Authors