title: The effect of timing of dexamethasone administration on its efficacy as a prophylactic antiemetic for postoperative nausea and vomiting.
abstract: We evaluated the timing effect of a 10-mg IV administration of dexamethasone on its efficacy as a prophylactic antiemetic on postoperative nausea and vomiting (PONV). One hundred twenty women (n = 40 in each of three groups) undergoing abdominal total hysterectomy under general anesthesia were enrolled in this randomized, double-blinded, placebo-controlled study. Group 1 received dexamethasone before the induction of anesthesia, Group 2 received dexamethasone at the end of anesthesia, and Group 3 received placebo (saline). The incidence of PONV was evaluated. During the postoperative period of 0-2 h, patients in Group 1 reported a less frequent incidence of PONV (15%) than those in Groups 2 and 3 (45% and 53%, respectively). Patients in Group 1 also requested less rescue antiemetic (8%) than those in Groups 2 and 3 (30% and 35%, respectively). During the postoperative period of 2-24 h, patients in both Groups 1 and 2 reported less frequent incidences of PONV (25% and 28%) and requested fewer rescue antiemetics (13% and 15%) than those in Group 3 (55% and 38%, respectively). In conclusion, the prophylactic IV administration of dexamethasone immediately before the induction, rather than at the end of anesthesia, was more effective in preventing PONV.
  
  
  CONCLUSIONS
  We evaluated the effect of timing of dexamethasone administration on its efficacy as a prophylactic antiemetic on postoperative nausea and vomiting. We found that dexamethasone, when given immediately before the induction of anesthesia, was more effective than when given at the end of anesthesia.
authors.affiliation: Department of Anesthesiology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan. painlab@tpts5.seed.net.tw
authors.forename: J J
authors.initials: JJ
authors.lastname: Wang
authors.forename: S T
authors.initials: ST
authors.lastname: Ho
authors.forename: J I
authors.initials: JI
authors.lastname: Tzeng
authors.forename: C S
authors.initials: CS
authors.lastname: Tang
mesh_terms: D000328:Adult; D000768:Anesthesia, General; D000932:Antiemetics / Q000008:administration & dosage*; D003907:Dexamethasone / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D007044:Hysterectomy; D008875:Middle Aged; D020250:Postoperative Nausea and Vomiting / Q000188:drug therapy / Q000517:prevention & control*
chemical_list: D000932:Antiemetics; D003907:Dexamethasone