M. Segerdahl et al., THE INFLUENCE OF ADENOSINE, KETAMINE, AND MORPHINE ON EXPERIMENTALLY-INDUCED ISCHEMIC PAIN IN HEALTHY-VOLUNTEERS, Anesthesia and analgesia, 79(4), 1994, pp. 787-791
Adenosine, intrathecally administered, produces antinociception in exp
erimental studies on animals. The effect of intravenous (IV) adenosine
on experimentally induced pain in humans has not been studied. The pr
esent single-blind, randomized, placebo-controlled study was conducted
in nine healthy volunteers. The pain-reducing effects of adenosine (7
0 mu g.kg(-1).min(-1) IV), morphine (0.1 mg/kg IV), ketamine (0.1 mg/k
g IV), adenosine + morphine, and adenosine + ketamine were compared to
each other and to placebo in random order. Ischemic pain was induced
by the submaximum effort tourniquet technique. Pain was assessed using
the visual analog scale (VAS, 0-100 mm). The sums of pain scores (SPS
) were compared and found significantly 30%-40% lower for adenosine as
well as for the other compounds and combinations (P < 0.03), compared
to placebo. The number of subjects who reached VAS 100 within 30 min
was significantly lower (P < 0.03) when receiving adenosine + morphine
(0/9) and adenosine + ketamine (2/9) than when receiving placebo (7/9
). This may indicate an additive effect on pain reduction when adenosi
ne is given in combination with morphine or ketamine. in conclusion, t
he results indicate that IV adenosine, as well as morphine and ketamin
e, can reduce experimentally induced ischemic muscle pain in healthy v
olunteers.