effect of different doses of ketamine on fentanyl-induced cough

Background: reflex cough is a common complication after fentanyl injection during anesthesia. several studies have tried different medications to control fentanyl-induced cough (fic).aim: our study evaluated the effect of different ketamine dosage on preventing fentanyl induced cough.methods: we randomly assigned 80 participants into four groups. group 1 was administered 0.15 mg/kg, group 2 received 0.2 mg/kg, group 3 was given 0.25 mg/kg of intravenous ketamine one minute prior to fentanyl injections, while group 4 received an equivalent volume of 0.9% normal saline.results: the incidence and severity of cough was evaluated by fic score. the incident of cough was significantly lower in groups 3, 2 and 1 in comparison to group 4 (0, 5, 30 respectively vs 85, p<0.001). the cough severity was significantly lower in groups 3, 2 and 1 in comparison to group 4 (p<0.001).conclusion: intravenous ketamine 0.25 mg/kg, significantly decreased the severity and frequency of cough compared with 0.20 and 0.15 mg/kg iv ketamine.