In a double-blind study, 2 mg of morphine in saline, or saline only, w
as given subcutaneously into a second-degree bilateral leg-burn injury
in 12 volunteers. Heat-pain thresholds and pressure-pain thresholds w
ere significantly increased by local morphine administration. These re
sults confirm experimental data demonstrating a peripheral antinocicep
tive effects of opioids in inflamed tissue.