Figure 2.
Mean VAS ratings of the subjective measures Drug Effect (top panel), Like Drug Effect (middle panel) and Bad Drug Effect (bottom panel) after administration of oxycodone (left column), tramadol (middle column) and codeine (right column) as a function of time following drug administration across the 6-hour session (n=9, ±1 SEM). Time course analysis indicated a main effect of dose on VAS Drug Effect (F[6,48]=5.6, p<.001), Like Drug Effect (F[6,48]=4.8, p<.001) and Bad Drug Effect (F[6,48]=3.8, p<.004). Dunnett post-hoc tests indicated both doses of oxycodone increased ratings of Drug Effect and Like Drug Effect, while the high dose of tramadol increased ratings of Bad Drug Effect, relative to placebo (p<.05). Filled symbols indicate means that were significantly different from placebo at a particular time point (Dunnett post-hoc, p<.05).