FIGURE 2.
Maximum pupillary constriction and drug liking VAS scores (Emax [mean ± SD]) induced by remifentanil (closed symbols) and saline (open symbols) following administration of placebo (day 1; green) and samidorphan (day 2; 10 mg in red; 20 mg in blue). Following placebo (day 1) or samidorphan (day 2) administration, remifentanil challenges were administered at 0.25, 1, 2, 4, and 8 hours postdose, and saline challenges were administered at 3 and 5 hours postdose. On days 3 through 9, remifentanil and saline challenges were administered in a randomized sequence 1 hour apart, centered around the same time of day as samidorphan administration on day 2. Maximum pupillary constriction was derived from repeated measurements taken at 2, 5, 10, 15, and 25 minutes following each remifentanil challenge.