Smoking does not alter the dose-requirements and the pharmacodynamics of rocuronium

Purpose: Controversial data about the effect of smoking on the dose-require ments and-the pharamcodynamics of rocuronium have been reported recently. T his study was conducted to evaluate the dose;requirements and the pharmacod ynamics of rocuronium in smokers using target controlled infusion. Methods: The dose-requirements of rocuronium for 60 min relaxation, using t arget controlled infusion, given under intravenous anaesthesia with propofo l, fentanyl and nitrous oxide was studied in 37 smokers and 37 nonsmokers. Initially 450 mu g.kg(-1) rocuronium were administered, neuromuscular effec ts were quantified by recording the single twitch response of the adductor pollicis muscle after ulnar nerve stimulation using a force transducer, and the neuromuscular block was kept at 80% by target controlled infusion thro ughout the procedure. Results: The dose-requirements for one hour relaxation were 867 +/- 116 mu g.kg(-1).hr(-1) for smokers (S) and 839 +/- 149 mu g.kg(-1).hr(-1) for non- smokers (NS), The duration to 10% and the spontaneous recovery from 25% to 75% of the control twitch response also showed no differences between S ( 1 7.2 +/- 3.4 min, 10.6 +/- 0.9 min) and NS (18.9 +/- 4.3 min, 10.9 +/- 3.2 m in), as well as maximum block, onset time and infusion rate. Conclusion: Smoking does not alter the dose-requirements for rocuronium and no effects on the onset time, degree of block, time to maximum block, dura tion 10% and spontaneous recovery index were observed.