Effects of promethazine or dexamethasone pretreatment on mivacurium-induced histamine release in children

Summary Objective To determine the effects of pretreatment with either promethazine or dexamethasone on mivacurium-induced histamine release in children. Methods Eighty ASA I–II children (4–10 years of age) scheduled for tonsillectomy and/or adenoidectomy were randomly divided into 4 groups (n = 20 per group) designated as either the rocuronium, mivacurium, dexamethasone (DXM), or promethazine group. Children in the DXM and promethazine groups were treated separately with intramuscular DXM 0.2 mg·kg−1 or promethazine 0.5 mg·kg−1 injections 60 min before operation. Radial artery blood samples were collected to quantify plasma histamine concentrations 1 min before and 1, 3, and 5 min after administration of the relaxant. Mean arterial pressure (MAP), heart rate (HR), and skin flushing were recorded at the same time. Results No significant decreases in plasma histamine concentrations were observed between groups; however, more stable MAP and HR and less skin flushing were observed in DXM group participants compared with individuals in the mivacurium group (P