The effect of dilution with glucose and prolonged injection time on dexamethasone-induced perineal irritation – A randomized controlled trial

Dexamethasone can be used to prevent nausea and vomiting after surgery, but there is concern that it may induced perineal irritation. The aim of this study was to investigate the attenuation effect of dilution and slow injection on dexamethasone-induced perineal irritation. In this prospective, randomized, double-blind study, a total of 400 patients were enrolled and allocated into four groups: Group I, receiving 2 mL dexamethasone (5 mg/mL), Group II, receiving 5 mL dexamethasone (2 mg/mL), Group III, receiving 10 mL dexamethasone (1 mg/mL), and Group IV receiving 20 mL dexamethasone (0.5 mg/mL). Dexamethasone was diluted with 5% glucose. The injection time of dexamethasone was less than 2 s in Group I, while it was 30 s in Groups II, III, and IV. The incidence, onset, duration, and severity of perineal irritation were recorded. The incidence of dexamethasone-induced perineal irritation was 49, 33, 17, and 15% in Groups I, II, III, and IV, respectively. Group IV had less severity than Group I in mild and moderate perineal irritation (P < 0.008). The onset and duration of perineal irritation of Groups II, III, and IV were significantly improved compared to Group I (P < 0.001). Dexamethasone-induced perineal irritation can be alleviated by dilution of dexamethasone to 0.5 mg/mL with 5% glucose combined with prolonged injection time of 30 s.