Intravenous lidocaine suppresses fentanyl-induced coughing: a double-blind, prospective, randomized placebo-controlled study.

IV lidocaine is effective in suppressing the cough reflex of tracheal intubation, extubation, bronchography, bronchoscopy, and laryngoscopy. We investigated this effect of lidocaine on fentanyl-induced cough in 502 patients of ASA physical status I and II scheduled for elective surgery. The patients were assigned to 2 equal groups to receive either lidocaine 1.5 mg/kg or placebo (0.9% saline) over 5 s 1 min before the administration of fentanyl 3 mug/kg in a randomized and double-blind fashion. Coughs were classified as coughing and graded as mild (1-2), moderate (3-4), or severe (5 or more). The results of the study suggest that IV lidocaine 1.5 mg/kg, when administered 1 min before fentanyl, is significantly effective in suppressing fentanyl-induced cough compared to placebo (0.9% saline) (218 versus 165 patients) (P < 0.002) but without affecting the severity of cough (P > 0.05).