A double-blind, placebo-controlled withdrawal trial of dexmethylphenidate hydrochloride in children with attention deficit hyperactivity disorder

J Child Adolesc Psychopharmacol. Winter 2004;14(4):542-54. doi: 10.1089/cap.2004.14.542.

Abstract

Objectives: d,l-threo-methylphenidate HCl (D,L-MPH) is the most common treatment of attention deficit hyperactivity disorder (ADHD). A previous report showed placebo-controlled efficacy for the purified d-isomer (dexmethylphenidate hydrochloride, d-MPH, Focalin) with a 2:1 potency compared to dl, and suggested a 6-hour duration of action. This study complements that report by studying the effect of placebo-controlled discontinuation and retesting the duration of action.

Methods: A 6-week, open-label titration of d-MPH (2.5-10 mg twice-a-day) was followed by a double-blind, placebo-controlled, 2-week withdrawal study of responders.

Results: In the open titration, 82% of the 89 enrolled patients achieved a Clinical Global Impression-Improvement (CGI-I) rating of much or very much improved. Only 5 patients discontinued for adverse events. Seventy-five patients continued into the placebo-controlled discontinuation. For the randomly assigned d-MPH (n=35) and placebo (n=40) groups, mean ages, respectively, were 10.1 +/- 2.9 and 9.9 +/- 2.7 years, 86% and 78% were male, and 70.6% and 80.0% took the ceiling dose of 10 mg twice-daily, respectively. Each group had 80% combined type ADHD and 20% inattentive type. By the end of the 2-week, placebo-masked withdrawal, significantly more placebo patients (24 of 39) than d-MPH continuers (6 of 35) relapsed (61.5% versus 17.1%, p=0.001). Compared to d-MPH continuers, placebo patients deteriorated significantly more in the 2-week period on teacher ratings of the 18 ADHD symptoms rated 0-3 (p=0.028), the 3 p.m. and 6 p.m. parent ADHD symptom ratings (p=0.0026 and p=0.0381, respectively), and clinic (2-3 p.m.) and home (6 p.m.) Math Tests (p=0.024 and p<0.0001, respectively). The 6 p.m. scores replicated the significant effect at 6 hours reported in the previous study.

Conclusions: d-MPH is safe, tolerable, and effective, with a 6-hour duration of effect suggested by the significant difference from placebo at 6 hours on a double-blind discontinuation.

Publication types

  • Clinical Trial
  • Multicenter Study
  • Randomized Controlled Trial

MeSH terms

  • Adolescent
  • Attention Deficit Disorder with Hyperactivity / drug therapy*
  • Central Nervous System Stimulants / administration & dosage*
  • Central Nervous System Stimulants / chemistry
  • Central Nervous System Stimulants / pharmacokinetics*
  • Child
  • Dexmethylphenidate Hydrochloride*
  • Dose-Response Relationship, Drug
  • Double-Blind Method
  • Drug Administration Schedule
  • Female
  • Humans
  • Male
  • Methylphenidate / administration & dosage*
  • Methylphenidate / chemistry
  • Methylphenidate / pharmacokinetics*
  • Psychiatric Status Rating Scales
  • Stereoisomerism
  • Treatment Outcome
  • Withholding Treatment

Substances

  • Central Nervous System Stimulants
  • Dexmethylphenidate Hydrochloride
  • Methylphenidate