Background: Intravenous administration of fentanyl derivatives can induce cough paradoxically. This study examined the incidence and severity of cough after a bolus of alfentanil and remifentanil.
Methods: Four hundred and sixty-five patients, aged 18-70 years, were allocated randomly to three groups to receive alfentanil 10 microg/kg, remifentanil 1 microg/kg or an equal volume of 0.9% saline intravenously over 10 s. Any episode of cough was classified as coughing and graded as mild (1-2), moderate (3-4) or severe (5 or more).
Results: The overall incidence of cough was higher in the opioid groups than in the saline group. The remifentanil group [39/150 patients; 26.0% (95% CI, 19.6-33.6%)] showed a higher incidence than the alfentanil group [11/152 patients; 7.2% (95% CI, 0.4-12.6%)] (P<0.001). There was no significant difference in the severity of cough between the alfentanil group and the remifentanil group.
Conclusion: This study demonstrated that equipotent boluses of alfentanil and remifentanil induced coughing, even though the incidence of cough after alfentanil administration was lower than that after remifentanil administration.