Abstract:  The main objective of the present study was to characterize the pharmacokinetic/pharmacodynamic (PK/PD) relationship of the effects of buprenorphine on cognitive functioning in healthy volunteers. Twenty-three male volunteers received 0.6 mg buprenorphine as an intravenous infusion over 150 min. The cognitive and psychomotor performance was evaluated before and at various times after drug administration by a test battery consisting of trail-making test for visual information processing, finger-tapping test for psychomotor speed, and continuous reaction time for attention. Non-linear mixed effect modelling was used in the analysis of the PK/PD relationships. Buprenorphine caused significant deficits in cognitive and psychomotor functioning. The time course of cognitive and psychomotor impairment was found to have a slow distribution to the biophase from plasma with PK/PD models involving an effect compartment providing the best descriptions of the time course of the data. The values for half-life of biophase equilibration were consistent between the neuropsychological tests in the range of 66.6–84.9 min. The time to onset and duration of the cognitive and psychomotor impairment of buprenorphine was determined by a slow distribution to the biophase.