Buprenorphine plasma and cerebrospinal fluid concentrations in osteoarthritis patients during low-dose transdermal patch dosing

Methods Fifty-six (56) patients scheduled for arthroplasty, received 7-day extended-release buprenorphine transdermal patches (5 µg/h) for five consecutive weeks, starting two weeks prior to the surgery. Simultaneous plasma and cerebrospinal fluid (CSF) samples were collected during spinal anesthesia. Results Median buprenorphine plasma and CSF concentrations at steady-state were 54 pg/mL (range 8.6 – 167 pg/mL) and 1.6 pg/mL (0.30 – 7.3 pg/mL), respectively. The median CSF/plasma -ratio was 3% (range 0.35 – 16%). Large between-subject variability was observed in the measured buprenorphine concentrations within the study population.