Intravenous lidocaine and ephedrine, but not propofol, suppress fentanyl-induced cough

Abstract

Purpose: The aim of this study was to evaluate the effectiveness of lidocaine, propofol and elphedrine in suppressing fentanyl-induced cough. Methods: One hundred and eighteen patients were randomly assigned into four groups and the following medications were given intravenously: patients in Group I (n = 31) received normal saline 2 mL, Group II (n = 29) received lidocaine 2 mg·kg-1, Group III (n = 30) received propofol 0.6 mg·kg-1 and Group IV (n = 28) received ephedrine 5 mg. At one minute after the study medication, fentanyl 2.5 μg·kg-1 was given intravenously within two seconds. The occurrence of cough and vital sign profiles were recorded within two minutes after fentanyl bolus by an anesthesiologist blinded to study design. Results: Sixty-five percent of patients in the placebo group had cough, whereas the frequency was significantly decreased in Groups II (14%) and IV (21%). Although a numerically lower frequency of cough was noted in Group III (37%), it was not statistically different from that of the placebo group. SpO2 decreased significantly in patients of Group III compared to placebo; one patient experienced hypoxemia necessitating mask ventilation. Patients in Group III showed a decrease in heart rate and systolic blood pressure (2 beats·min-1 and 8 mmHg vs baseline). Patients in Group IV showed an increase in both measurements (5 beats·min-1 and 8 mmHg vs baseline). No truncal rigidity was observed throughout the study. Conclusions: Intravenous lidocaine 2 mg·kg-1 or ephedrine 5 mg, but not propofol 0.6 mg·kg-1, was effective in preventing fentanyl-induced cough. The results provide a convenient method to decrease fentanyl-induced cough.