The effect of dexamethasone injection on cisatracurium-induced neuromuscular block was compared according to different injection time points.

One hundred seventeen patients were randomly assigned to three groups: 8 mg of dexamethasone injected intravenously 2–3 h before anesthesia (group A), just before anesthesia induction (group B), and at the end of surgery (control group). Three minutes after anesthesia induction, intubation was performed without neuromuscular blockers, and acceleromyography was initiated. All patients received 0.05 mg/kg cisatracurium; the onset time and recovery profiles were recorded.

Eighty patients were finally enrolled. The onset time (median [interquartile range], seconds) was significantly hastened in group A (520.0 [500.0–560.0], n = 30) compared to that in group B (562.5 [514.0–589.0], n = 22) (P = 0.008) and control group (586.5 [575.0–642.5], n = 28) (P < 0.001). The onset time in group B was faster than the control group (P = 0.015). The recovery time [mean (95% CI) minutes] was significantly hastened in group A [28.5 (27.3–29.6)] compared to that in group B [32.3 (31.0–33.6)] (P < 0.001) and control group [30.9 (29.9–31.8)] (P = 0.015). The total recovery time was significantly hastened more in group A [47.1 (45.5–48.6)] than group B [52.8 (51.6–54.0) minutes] (P < 0.001) and control group [50.5 (48.7–52.3) minutes] (P = 0.008).

A single dose of 8 mg of dexamethasone hastened the onset and total recovery times of cisatracurium-induced block by approximately 15 and 9%, respectively if administered 2–3 h prior to surgery.