Intravenous
naloxone has been claimed to produce
pain relief in
opioid-resistant central post-
stroke pain (CPSP, '
thalamic syndrome'). In a double-blind trial, carried out in 20 patients with established CPSP,
naloxone (up to 8 mg in 20 ml vehicle) was tested against
normal saline; each patient was randomly given
naloxone or saline and the other substance 2 or 3 weeks later. VAS and verbal
pain scores were obtained immediately before and after
naloxone or saline injection, and subjective ratings followed for 2 weeks. Three patients obtained transient
pain relief with
naloxone, 4 with saline, and another 4 with both. Statistical tests failed to show any influence of giving
naloxone first or second. In all cases except one,
pain relief had disappeared by the evening of the day on which the test was performed; one case, following
naloxone, continued to experience
pain relief until the following morning. We therefore conclude that intravenous
naloxone is of no value in alleviating the
pain of CPSP.