This study aimed to compare in vitro two syringe changeover techniques to determine which was better at minimising variations in norepinephrine (NE) delivery: the manual quick-change or automated technique. NE concentration was measured continuously using a UV spectrophotometer, and infusion flow rate was monitored by an infusion pump tester. Syringe changeovers were made with either of the two techniques studied. Relays induced disturbances in drug delivery. The temporary increase in NE mass flow rate was significantly higher with manual relays than with automated ones. The automated relay offered a better control of the amounts of NE administered than the quick-change technique.