Subhypnotic doses of propofol do not possess antidopaminergic properties

In order to investigate the possible interactions of propofol with the dopaminergic system, a prospective, randomized, double-blind, placebo-controlled study was performed on the profile of prolactin secretion, since prolactin blood levels are known to increase when dopaminergic receptors are blocked. Ten fasting female patients scheduled to receive cancer chemotherapy were allocated to receive either propofol at a rate of 1 mg.kg-1.h-1 or Intralipid 0.1 ml.kg-1.h-1. The study included two consecutive chemotherapy cycles; each patient received in a random order propofol or Intralipid. The infusions were started 4 h prior to induction of chemotherapy; prolactin blood levels were determined at time 0, 30, 60, 120, and 240 min (end of the study period). The basal prolactin blood levels were 14.2 +/- 4.3 vs 12.8 +/- 2.7 and 10.7 +/- 1.7 vs 14.0 +/- 3.6 ng/mL at the end of the study for propofol and Intralipid, respectively. These results suggest that the antiemetic properties of propofol are not mediated via interactions with the dopaminergic system.