Figure 2.

Results from painful skin stimulation. Stimulus intensities evoking skin pain tolerance threshold to heat stimulation at baseline, 30, 60 and 90 min after drug administration. Compared with placebo (white) and morphine (30 mg, grey) administration of oxycodone (15 mg, black) resulted in higher temperatures. The error bars represent SEM. To eliminate errors relating to differences in baseline pain recordings (illustrated by a lower baseline value for morphine in the figure), the change in stimulus intensity relative to baseline was used in the statistical analysis