Dipyridamole in the treatment of schizophrenia: adenosine-dopamine receptor interactions.
OBJECTIVE
There is growing interest in investigating the adenosine-dopamine interaction in the ventral striatum. Adenosine plays a role opposite to dopamine in the striatum and adenosine antagonists, like caffeine, produce similar effects to increased dopaminergic neurotransmission in the striatum. In particular, a strong antagonistic interaction between adenosine A2A and dopamine D2 receptors takes place in the striopallidal GABAergic neurones. Therefore, adenosine agonists or uptake inhibitors provide a potential new treatment for schizophrenia. We undertook a pilot trial to investigate whether the combination of haloperidol with dipyridamole, an uptake inhibitor of adenosine, was more effective than haloperidol alone.


METHODS
Thirty patients who met the DSM IV criteria for schizophrenia completed the study. Patients were allocated in a random fashion, 16 to haloperidol 20 mg/day plus dipyridamole 75 mg/day and 14 to haloperidol 20 mg/day plus placebo.


RESULTS
Although both protocols significantly decreased the score of the positive, negative and general psychopathological symptoms over the trial period, the combination of haloperidol and dipyridamole was significantly better than haloperidol alone in decreasing positive and general psychopathology symptoms as well as PANSS total scores.


CONCLUSIONS
Dipyridamole may be of therapeutic benefit in treating schizophrenia in combination with neuroleptics. However, a larger study to confirm our results is warranted.
Akhondzadeh
S
S
Roozbeh Psychiatric Hospital, Tehran University of Medical Sciences, South Kargar Avenue, Tehran 13334, Iran. s.akhond@neda.net
Shasavand
E
E
Jamilian
H
H
Shabestari
O
O
Kamalipour
A
A
D000328:Adult; D014150:Antipsychotic Agents / Q000008:administration & dosage; D004176:Dipyridamole / Q000494:pharmacology*; D004359:Drug Therapy, Combination; D005260:Female; D006220:Haloperidol / Q000008:administration & dosage; D006801:Humans; D008297:Male; D008875:Middle Aged; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D010865:Pilot Projects; D011954:Receptors, Dopamine / Q000187:drug effects* / Q000502:physiology; D018047:Receptors, Purinergic P1 / Q000187:drug effects* / Q000502:physiology; D012559:Schizophrenia / Q000188:drug therapy*; D016896:Treatment Outcome
D014150:Antipsychotic Agents; D010726:Phosphodiesterase Inhibitors; D011954:Receptors, Dopamine; D018047:Receptors, Purinergic P1; D004176:Dipyridamole; D006220:Haloperidol