Subhypnotic Doses of Propofol Do Not Possess Antidopaminergic Properties

Abstract

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.

Intravenous Subhypnotic Propofol in Central Pain

“…However, propofol is 5 times as effective at equipotent doses for CP control. 3 It is important to remark that propofol at nonsedating doses has exclusive GABA-A selectivity and no effect on other transmitters/modulators and ion channels 21,[29][30][31][32][33][34][35][36][37][38][39] ; also, at nonsedating doses, it first targets the cortex (layers III and V), and only successively the thalamus, basal ganglia, and mesencephalon. 3 Unlike diazepam, propofol may activate the receptor-associated Clchannel in the absence of GABA 28 : this might support the speculation that GABA is actually downregulated in CP.…”

Nausea and Vomiting After Strabismus-Surgery: A Randomized Comparison of Isoflurane, Enflurane, Sevoflurane and Propofol

“…In support of this hypothesis Honkavaara et al found propofol in subhypnotic doses to be effective in preventing retching and vomiting after isoflurane anesthesia, following middle ear surgery compared to thiopentone, without implications on patient`s vigilance [30]. One possible specific antiemetic mechanism, a dopamine antagonism, was suggested by Di Florio [31] but rejected in a controlled trial, investigating the impact of propofol on serum prolactin level [32]. In a disagreement with specific antiemetic action, Hvarfner et al pointed out that propofol and midazolam infusion were equally effective to prevent apomorphin induced emesis, while both agents exceeded the effect of placebo [33].…”