Systemic adenosine infusion reduces the area of tactile allodynia in neuropathic pain following peripheral nerve injury: a multi-centre, placebo-controlled study

Systemic adenosine has been shown in earlier case reports and a small place bo-con trolled study to reduce pathological sensory dysfunction such as tac tile allodynia in neuropathic pain. To evaluate this further, the effects o f systemic adenosine infusion (50 mug/kg/min for 60 min) on tactile sensory dysfunction and pain was evaluated in 26 patients suffering peripheral neu ropathic pain characterized by dynamic tactile allodynia. A randomized, cro ss-over, double-blind, placebo-controlled technique was used in this multi- centre study. Psychophysical methods were used to evaluate sensory dysfunct ion and spontaneous pain. The area of dynamic tactile allodynia was signifi cantly reduced by adenosine compared with placebo (p = 0.043), but spontane ous pain and tactile pain threshold were not significantly improved compare d with the effects of placebo treatment. As a secondary outcome, a higher i ncidence of positive subjective effects on the clinical pain condition, in a few cases with long duration (several months), following adenosine treatm ent was found when the global effect of respective treatment was assessed ( p = 0.028). The results demonstrate involvement of adenosine receptor-sensi tive pain mechanisms in some aspects of the sensory dysfunction often found in neuropathic pain. (C) 2001 European Federation of chapters of the Inter national Association for the Study of Pain.