Smoking increases the requirement for rocuronium

Abstract

Purpose: To compare the potency of rocuronium in non-smokers and smokers during general anaesthesia. Methods: In a randomized, open clinical study, 40 patients, 17-62 yr of age, were anaesthetized with propofol, alfentanil and nitrous oxide in oxygen. After obtaining individual dose-response curves for rocuronium, bolus doses of rocuronium were given to maintain neuromuscular block at 90-99 % for 60 min. Evoked adductor pollicis electromyography (EMG) was used to monitor neuromuscular block. Results: The ED95 values (± SEN) for rocuronium were 460.5 ± 28.9 and 471.5 ± 22.1 μg · kg-1 for nonsmokers and smokers, respectively (P:NS). However, doses of rocuronium to maintain 90-99 % neuromuscular block (± SEN) were 620.1 ± 46.7 and 747.4 ± 56.0 μg · kg-1·hr-1 for non-smokers and smokers, respectively (P = 0.0504). Conclusion: The results may indicate increased metabolism of rocuronium in smokers rather than increased requirement of rocuronium at the receptor site.