THE PHARMACOKINETICS AND PHYSIOLOGICAL-EFFECTS OF BUPRENORPHINE INFUSION IN PREMATURE NEONATES

1 The pharmacokinetics and physiological effects of buprenorphine were studied in 12 newborn premature neonates (27 to 32 weeks gestational age) who were given a loading dose of 3.0 mug kg-1 of buprenorphine followed by an intravenous infusion of 0.72 mug kg-1 h-1 of buprenorphine. Plasma concentrations of buprenorphine were measured during the infusion, at steady-state and for 24 h after the cessation of the buprenorphine infusion. 2 The mean steady-state plasma buprenorphine concentration (+/- s.d.) for an infusion rate of 0.72 mug kg-1 h-1 was 4.3 +/- 2.6 ng ml-1. 3 Buprenorphine clearance was 0.23 +/- 0.07 l h-1 kg-1, the elimination half-life was 20 +/- 8 h and the volume of distribution was 6.2 +/- 2. 11 l kg-1. 4 Small but significant falls were noted in systolic blood pressure at 6 h and heart rate at 1, 6 and 12 h after the administration of buprenorphine, but these did not appear to cause any clinical deterioration. 5 Four of the 12 subjects studied required an increase in the infusion rate of buprenorphine to achieve adequate sedation. 6 The results suggest that this dosing regimen of buprenorphine is safe but may not be as effective as other opioids in producing sedation and analgesia in premature newborns.