Background: Fentanyl is one of pain medication usually used in anesthetic practice and one common problem after intravenous injection is inducing cough. A 0.5 mg/kg of lidocaine could suppress fentanyl-induced cough, however, the side effect of exceeding doses of lidocaine may cause arrhythmogenic effects and the vasodila­tory effects of lidocaine may possibly aggravate cardiovascular depression.

 

Objectives: The study aimed to compare the efficacy of 0.25 mg/kg and 0.5 mg/kg intravenous lidocaine regarding fentanyl-induced cough in general anesthesia.

 

Methods: This study was a randomized double-blinded controlled trial. In all 139 participants, who underwent elective surgery between the ages of 18 to 60 years, were allocated in two groups, to receive lidocaine 0.25 mg/kg and 0.5 mg/kg over two minutes before 1 μg/kg of intravenous fentanyl. Coughing was assessed and classified into 3 grades as mild, moderate, or severe. The risk factors of fentanyl-induced cough and side effects were also noted.

Results: Thirteen patients (18.8%) in the 0.25% lidocaine group and eleven patients (15.7%) in the 0.5% lidocaine group experienced fentanyl induced cough. No significant difference was found in the incidence and severity of cough between the two groups (P>0.05).

Conclusion: The present findings indicated that pre-operative IV lidocaine 0.25 mg/kg could be considered an alternative dose to suppress fentanyl-induced cough.