ABSTRACT
INTRODUCTION: This multiple-dose pharmacokinetic study has a randomized, double-blind, placebo-controlled, parallel-group design with three dosing regimens. Healthy subjects received repeated doses of acetaminophen (4 then 6 g/d or 4 then 8 g/d) or placebo. METHODS: The disposition of acetaminophen and its metabolites and the tolerability of increased acetaminophen doses over 3 days of continuous consumption were characterized. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities measured throughout the study were consistent across the acetaminophen 4, 6, and 8 g/d dose levels and with placebo. RESULTS: Serum aminotransferase activities did not exceed the upper limit of the reference range (ULRR), except for one subject with an AST of 43 U/L (ULRR, 42 U/L), which was not considered clinically significant. All doses were generally well tolerated. CONCLUSIONS: In a multiple-dose pharmacokinetics study of 4, 6, and 8 g/d of acetaminophen for 3 days, multiple aminotransferase determinations demonstrated no clinically important elevations at 1, 1.5, or 2 times the maximum recommended acetaminophen dose.
Subject(s)
Acetaminophen/pharmacokinetics , Alanine Transaminase/blood , Analgesics, Non-Narcotic/pharmacokinetics , Aspartate Aminotransferases/blood , Adolescent , Adult , Dose-Response Relationship, Drug , Double-Blind Method , Female , Humans , Male , Middle Aged , Reference ValuesABSTRACT
BACKGROUND: Despite the persistence of attention-deficit/hyperactivity disorder (ADHD) into adolescence, little is known about the efficacy and tolerability of stimulant medications in this age group. OBJECTIVE: To report the results of a multisite controlled study among adolescents with ADHD evaluating the efficacy and tolerability of osmotic-release oral system (OROS) methylphenidate. DESIGN: Adolescents (N = 220) having a confirmed Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition diagnosis of ADHD underwent dose titration to identify dosages of OROS methylphenidate that improved symptoms to predefined criteria. Subjects successfully completing the dose titration phase (n = 177) (ie, tolerated and responded to treatment and adhered to the protocol) were randomized to receive 2 weeks' treatment with their individualized dosage of OROS methylphenidate (18, 36, 54, or 72 mg once daily) or placebo. Treatment effectiveness was measured using investigator, parent, and adolescent assessments of ADHD. RESULTS: A significant reduction from baseline in the investigator-rated ADHD Rating Scale, the primary efficacy measure, was found with OROS methylphenidate treatment compared with placebo. Similar findings were noted with parent- and adolescent-report measures. Based on a Clinical Global Impression improvement subscale score of much or very much improved, 52% of subjects in the OROS methylphenidate group improved compared with 31% receiving placebo. Thirty-seven percent of subjects required the maximum dosage of 72 mg/d. The incidence of drug-related adverse events was similar between the 2 study groups. CONCLUSION: In adolescents, once-daily OROS methylphenidate significantly reduced ADHD symptoms and was well tolerated using dosages up to 72 mg/d.