title: Dipyridamole monotherapy in schizophrenia: pilot of a novel treatment approach by modulation of purinergic signaling.
abstract: BACKGROUND
  Emerging data indicate the neuromodulator adenosine may play a role in the therapeutics of schizophrenia. Adenosine A(2A) receptor stimulation exerts a functional antagonism at postsynaptic D(2) receptors. Data from animal models relevant to schizophrenia support a therapeutic effect of modulating adenosinergic transmission in the ventral striatum. One previous clinical trial showed superiority of adjunctive dipyridamole, an adenosine reuptake inhibitor, compared to placebo in ameliorating positive symptoms in schizophrenia patients.
  
  
  OBJECTIVE
  The aim of this study was to examine the effects of dipyridamole monotherapy of 200 mg/day on positive and negative symptoms, with the goal of determining dosing for future adjunctive studies in schizophrenia.
  
  
  METHODS
  Twenty symptomatic schizophrenia participants were randomized to a 6-week double-blind trial comparing olanzapine (20 mg/day) to dipyridamole monotherapy (200 mg/day). Thirteen participants completed the treatment phase (eight on dipyridamole; five on olanzapine).
  
  
  RESULTS
  The olanzapine group showed a trend (p = 0.08) for superiority on BPRS total scores (mean ± SD: total BPRS score decreasing from 36.8 ± 2.3 at week 1, to 33.2 ± 5.5 at the end of the study). The mean total BPRS scores decreased from 36.4 ± 5.3 to 34.0 ± 7.7 in the dipyridamole group.
  
  
  CONCLUSIONS
  Although these pilot data do not support a significant antipsychotic effect of dipyridamole monotherapy, the results provide some evidence for examining dipyridamole (200 mg/day) as adjunct to symptomatic antipsychotic-treated schizophrenia patients.
authors.affiliation: Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA. Iwonodi@mprc.umaryland.edu
authors.forename: Ikwunga
authors.initials: I
authors.lastname: Wonodi
authors.forename: Hirekatur V
authors.initials: HV
authors.lastname: Gopinath
authors.forename: Judy
authors.initials: J
authors.lastname: Liu
authors.forename: Helene
authors.initials: H
authors.lastname: Adami
authors.forename: L Elliot
authors.initials: LE
authors.lastname: Hong
authors.forename: Robert
authors.initials: R
authors.lastname: Allen-Emerson
authors.forename: Robert P
authors.initials: RP
authors.lastname: McMahon
authors.forename: Gunvant K
authors.initials: GK
authors.lastname: Thaker
mesh_terms: D000293:Adolescent; D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D001569:Benzodiazepines / Q000627:therapeutic use*; D010054:Brief Psychiatric Rating Scale; D004176:Dipyridamole / Q000494:pharmacology / Q000627:therapeutic use*; D004311:Double-Blind Method; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D000077152:Olanzapine; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D010865:Pilot Projects; D012559:Schizophrenia / Q000188:drug therapy* / Q000503:physiopathology; D012565:Schizophrenic Psychology; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D014150:Antipsychotic Agents; D010726:Phosphodiesterase Inhibitors; D001569:Benzodiazepines; D004176:Dipyridamole; D000077152:Olanzapine