title: Differences in regional brain metabolic responses between single and repeated doses of methylphenidate.
abstract: Studies investigating the acute effects of drugs of abuse on human brain metabolism have measured single doses whereas these drugs are mostly taken repeatedly. Here we compared the brain metabolic response to intravenous methylphenidate when given after a single dose to that when given after two sequential doses. Methylphenidate-induced changes in metabolism differed; whereas single doses tended to decrease metabolism, repeated doses tended to increase it, and these differences were significant in frontal, parietal and occipital cortices and hippocampus. This indicates that methylphenidate's metabolic effects vary with acute previous exposure and highlights the importance of studying drugs after single and repeated administration.
authors.affiliation: Medical Department, Brookhaven National Laboratory, Upton, NY 11973, USA. volkow@bnl.gov
authors.forename: N D
authors.initials: ND
authors.lastname: Volkow
authors.forename: G J
authors.initials: GJ
authors.lastname: Wang
authors.forename: J S
authors.initials: JS
authors.lastname: Fowler
authors.forename: R
authors.initials: R
authors.lastname: Hitzemann
authors.forename: J
authors.initials: J
authors.lastname: Gatley
authors.forename: Y S
authors.initials: YS
authors.lastname: Ding
authors.forename: C
authors.initials: C
authors.lastname: Wong
authors.forename: N
authors.initials: N
authors.lastname: Pappas
mesh_terms: D000328:Adult; D001519:Behavior / Q000187:drug effects; D001921:Brain / Q000000981:diagnostic imaging / Q000187:drug effects*; D002319:Cardiovascular System / Q000187:drug effects; D000697:Central Nervous System Stimulants / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008774:Methylphenidate / Q000008:administration & dosage / Q000494:pharmacology*; D016037:Single-Blind Method; D014055:Tomography, Emission-Computed
chemical_list: D000697:Central Nervous System Stimulants; D008774:Methylphenidate