“…Many factors have been associated with fentanyl-induced cough, such as drug dosage and concentration, order of drug administration, intravenous injection rate and site [8], individual physical condition, age, sex, weight, disease history, smoking, and family genetics. A number of techniques have been applied to reduce the incidence of fentanylinduced cough, including the use of betamethasone (8.3 vs. 35%), dexamethasone (6.3 vs. 21.3%) [9], ephedrine (21 vs. 65%) [10], lidocaine (13.1%) [11], ketamine (7.2 vs. 21.6%) [12], and propofol (6.7%) [13], a change the order of administering the drugs, the speed of fentanyl administration, and fentanyl concentration. The use of the drugs in these earlier studies was unable to completely prevent fentanyl-induced cough, and some of them are very limited in terms of their clinical application.…”