Adenosine and pain relief: A clinical overview Segerdahl, Märta; Sollevi, Alf
Drug development research,
November ‐ December 1998, Letnik:
45, Številka:
3-4
Journal Article, Conference Proceeding
Systemic adenosine has been shown in earlier case reports and a small placebo‐controlled study to reducepathological sensory dysfunction such as tactile allodynia in neuropathic pain. To evaluate ...this further, the effects of systemic adenosine infusion (50 μg/kg/min for 60 min) on tactile sensory dysfunction and pain was evaluated in 26 patients suffering peripheral neuropathic pain characterized by dynamic tactile allodynia. A randomized, cross‐over, double‐blind, placebo‐controlled technique was used in this multi‐centre study. Psychophysical methods were used to evaluate sensory dysfunction and spontaneous pain. The area of dynamic tactile allodynia was significantly reduced by adenosine compared with placebo (p=0.043), but spon‐taneous pain and tactile pain threshold were not significantly improved compared with the effects of placebo treatment. As a secondary outcome, a higher incidence of positive subjective effects on the clinical pain condi‐tion, in a few cases with long duration (several months), following adenosine treatment was found when theglobal effect of respective treatment was assessed (p=0.028). The results demonstrate involvement of adenosine receptor‐sensitive pain mechanisms in some aspects of the sensory dysfunction often found in neuropathic pain.
The effect of adenosine on tactile allodynia (secondary hyperalgesia) was studied in 6 healthy volunteers, using a double-blind, placebo controlled, cross-over design. Tactile allodynia was induced ...by topical application of mustard oil on the skin of the volar aspect of the forearm. Adenosine (50 micrograms kg-1 min-1) or saline was given intravenously for 20 min before the mustard oil application and continued for another 50 min. The tactile allodynic areas for brush and von Frey filament stimulation were both significantly reduced by approximately 50% during adenosine infusion, compared with placebo. The threshold for eliciting allodynia with von Frey filaments was not influenced by adenosine. The study shows that adenosine can reduce the area of mustard oil induced tactile allodynia.
Experimental studies indicate that the effects of spinal cord stimulation (SCS) on 'hypersymptoms' in neuropathic pain conditions may at least partly be mediated via GABAergic and adenosine-dependent ...mechanisms. Concomitant intrathecal administration of receptor-active drugs modulating the function of the GABA and adenosine systems may both depress and enhance the effects of SCS. The first few patients with simultaneous intrathecal administration of the GABAB agonist baclofen and/or adenosine together with SCS, when the stimulation alone proved insufficient, are reported.
