Pharmacokinetic-pharmacodynamic relationships of cognitive and psychomotor effects of intravenous buprenorphine infusion in human volunteers.

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.