Impaired activity of the purinergic system is a plausible common factor that could be responsible for many aspects of
schizophrenia. Based on purinegic hypothesis of
schizophrenia, pharmacological treatments enhancing
adenosine activity could be effective treatment in
schizophrenia.
Propentofylline is a novel xantine derivative which is being developed for treatment of degenerative and
vascular dementia. It enhances extracellular
adenosine level via inhibition of
adenosine uptake. The purpose of the present investigation was to assess the efficacy of
propentofylline as an adjuvant agent in the treatment of chronic
schizophrenia in an 8-week double blind and placebo controlled trial. Eligible participants in this study were 50 patients with chronic
schizophrenia. All patients were inpatients and were in the active phase of the illness, and met DSM-IV-TR criteria for
schizophrenia. Patients were allocated in a random fashion, 25 to
risperidone 6 mg/day plus
propentofylline 900 mg/day (300 mg
TDS) and 25 to
risperidone 6 mg/day plus placebo. The principal measure of the outcome was Positive and Negative Syndrome Scale (PANSS). Although both protocols significantly decreased the score of the positive, negative and general psychopathological symptoms over the trial period, the combination of
risperidone and
propentofylline showed a significant superiority over
risperidone alone in the treatment of positive symptoms, general psychopathology symptoms as well as PANSS total scores. The means Extrapyramidal Symptoms Rating Scale for the placebo group were higher than in the
propentofylline group over the trial. However, the differences were not significant. The present study indicates
propentofylline as a potential adjunctive treatment strategy for chronic
schizophrenia. Nevertheless, results of larger controlled trials are needed, before recommendation for a broad clinical application can be made.