Premedication with intravenous dexmedetomidine-midazolam suppresses fentanyl-induced cough.

BACKGROUND: The incidence of fentanyl-induced cough (FIC) occurs frequently during induction of general anesthesia, and methods to prevent it are needed. In this study, we hypothesized that premedication with intravenous dexmedetomidine-midazolam can suppress FIC effectively. METHODS: A total of 440 patients of ASA I or II, aged 18-65 years, weighing 41-90 kg, undergoing elective surgery were randomized into four groups of 110 each, using computer-generated random numbers. Group S + S: normal saline 0.15 ml/kg + normal saline 0.06 ml/kg; Group S + M: normal saline 0.15 ml/kg + midazolam 0.06 mg/kg; Group D + S: dexmedetomidine 0.6 μg/kg + normal saline 0.06 ml/kg; Group D + M: dexmedetomidine 0.6 μg/kg + midazolam 0.06 mg/kg. After receiving the above-mentioned drugs, all patients received i.v. fentanyl (3 μg/kg). After fentanyl administration, the onset time and the severity of cough for 1 min were recorded. Severity of coughing was graded as mild (1-2), moderate (3-5) and (>5) based on the number of cough per minute. RESULTS: Forty-five (40.9%) patients had cough in Group S + S, 70 (63.6%) in Group S + M and 25 (22.7%) in Group D + S. None of the patients in Group D + M had any cough. The total incidence of cough was significantly higher (P < 0.01) in Group S + M in comparison to that in other groups. The onset time of cough was significantly shorter in Group S + M (13.8 ± 3.8 s) than in Group S + S (18.7 ± 3.9 s, P < 0.01) or Group D + S. (18.2 ± 3.2 s, P < 0.01). However, there was no significant difference among groups in cough severity. CONCLUSIONS: Pretreatment with dexmedetomidine-midazolam could completely suppress FIC caused by fentanyl 3 μg/kg injection within 2 s.