Comparing the Efficacy of Dexmedetomidine, Dexamethasone, and Metoclopramide in Postoperative Nausea and Vomiting of Tympanomastoidectomy Surgery: A Double‑Blind Randomized Clinical Trial

Abstract

Objective: Postoperative nausea and vomiting (PONV) are of the most common complications after anesthesia and surgery that affects 20%–30%
of patients. This study aimed to examine the efficacy of dexmedetomidine (DEXM), dexamethasone (DEXA), and metoclopramide (METO)
on the reduction of PONV after tympanomastoidectomy. Materials and Methods: In a clinical trial study, 90 patients who undergoing
tympanomastoidectomy surgery were assigned to DEXM (1 µg/kg/intravenous [IV]), DEXA (0.1 mg/kg/IV), and METO (0.15 mg/kg/IV)
groups by block randomization method. The initial vital signs and vomiting score as responses to treatment were assessed using visual analog
scale through 24 h (6, 12, 18, and 24) after the end of surgery. The vomiting score varied from 0 (no vomiting) to 100 (the worst possible
vomiting). One-way analysis of variance (ANOVA), paired t-test, and repeated measure ANOVA was used for statistical analysis in SPSS
version 12.5 (SPSS Inc., Chicago, IL, USA). Results: The incidence of PONV was 10%, in DEXM 0%, DEXA 6.7%, and 23.3% in METO.
Vomiting score is much lower for the DEXM than for the other two groups, and rather rapidly declined 18 h after the intervention. The difference
of time 6–24 was significant among three groups (P < 0.05). A greater reduction observed in vomiting total scores in DEXM group compared
to other groups at time 18–24 as well as time 6–24. Conclusion: DEXM, DEXA, and METO are effective drugs for control of PONV after
tympanomastoidectomy surgery. However, the reduction effect of DEXM and DEXA in vomiting total scores was higher than METO.