title: Extended-release methylphenidate for treatment of amphetamine/methamphetamine dependence: a randomized, double-blind, placebo-controlled trial.
abstract: OBJECTIVE
  To assess the efficacy of methylphenidate as a substitution therapy for amphetamine/methamphetamine dependence in Finland and New Zealand.
  
  
  METHODS
  Parallel-group, double-blind, randomized placebo-controlled trial.
  
  
  METHODS
  Out-patient care.
  
  
  METHODS
  Amphetamine-/methamphetamine-dependent, aged 16-65 years.
  
  
  METHODS
  The primary outcome measure was presence/absence of amphetamine/methamphetamine in urine samples collected twice weekly. Secondary measures included treatment adherence, alterations in craving scores and self-reported use. Primary analysis was by intention-to-treat (ITT). The study drug, methylphenidate (as Concerta(®) ), was up-titrated over 2 weeks to a maximum dose of 54 mg daily and continued for a further 20 weeks. Doses were given under daily supervision at the clinics.
  
  
  RESULTS
  Seventy-nine participants were randomized (40 methylphenidate; 39 placebo); 76 received allocated treatment and 27 completed the trial. ITT analysis (n = 78) showed no statistically significant difference in the percentage of positive urines between the methylphenidate and placebo arms (odds ratio: 0.95, 95% confidence interval: 0.83-1.08). However, there was a significant difference (P < 0.05) between the active and placebo arms in retention, the placebo arm displaying a significantly lower retention from 6 weeks that persisted until the end of the trial.
  
  
  CONCLUSIONS
  The trial failed to replicate earlier findings suggesting that methylphenidate was superior to placebo. The low retention rate confounded the ability to draw firm conclusions about efficacy. The higher retention rate was observed in the methylphenidate arm. Any replication of this work would need to consider alternatives to the rigid clinic attendance criteria, and consider an increased dose.
authors.affiliation: Waitemata District Health Board, Auckland, New Zealand. wayne.miles@waitematadhb.govt.nz
authors.forename: S Wayne
authors.initials: SW
authors.lastname: Miles
authors.forename: Janie
authors.initials: J
authors.lastname: Sheridan
authors.forename: Bruce
authors.initials: B
authors.lastname: Russell
authors.forename: Rob
authors.initials: R
authors.lastname: Kydd
authors.forename: Amanda
authors.initials: A
authors.lastname: Wheeler
authors.forename: Carina
authors.initials: C
authors.lastname: Walters
authors.forename: Greg
authors.initials: G
authors.lastname: Gamble
authors.forename: Peta
authors.initials: P
authors.lastname: Hardley
authors.forename: Maree
authors.initials: M
authors.lastname: Jensen
authors.forename: Kimmo
authors.initials: K
authors.lastname: Kuoppasalmi
authors.forename: Pekka
authors.initials: P
authors.lastname: Tuomola
authors.forename: Jaana
authors.initials: J
authors.lastname: Föhr
authors.forename: Outi
authors.initials: O
authors.lastname: Kuikanmäki
authors.forename: Helena
authors.initials: H
authors.lastname: Vorma
authors.forename: Raimo
authors.initials: R
authors.lastname: Salokangas
authors.forename: Antti
authors.initials: A
authors.lastname: Mikkonen
authors.forename: Mika
authors.initials: M
authors.lastname: Kallio
authors.forename: Jussi
authors.initials: J
authors.lastname: Kauhanen
authors.forename: Vesa
authors.initials: V
authors.lastname: Kiviniemi
authors.forename: Jari
authors.initials: J
authors.lastname: Tiihonen
mesh_terms: D000293:Adolescent; D000328:Adult; D019969:Amphetamine-Related Disorders / Q000188:drug therapy*; D000662:Amphetamines / Q000009:adverse effects; D000697:Central Nervous System Stimulants / Q000009:adverse effects; D018765:Dopamine Uptake Inhibitors / Q000008:administration & dosage*; D004311:Double-Blind Method; D005260:Female; D005387:Finland; D006801:Humans; D008297:Male; D008694:Methamphetamine / Q000009:adverse effects; D008774:Methylphenidate / Q000008:administration & dosage*; D008875:Middle Aged; D009520:New Zealand; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000662:Amphetamines; D000697:Central Nervous System Stimulants; D018765:Dopamine Uptake Inhibitors; D008774:Methylphenidate; D008694:Methamphetamine