Methods. The investigators carried out a double-blind, randomized, controlled trial. The branded molecule of remifentanil (group O, n=29) was compared against the two unbranded molecules (group A, n=29; group B, n=32) during anesthetic induction and tracheal intubation in adult patients American Society of Anesthesiology Physical Status Classification = I without predictors for difficult airway. The target controlled infusion (TCI) doses evaluated were 6, 8 and 10 ng/ml with the Minto model. Induction was complemented with propofol 5 mg/ml (TCI) with the Schneider model and rocuronium 0.6 mg/kg. The primary outcome was defined as the difference in mean arterial pressure and heart rate pre-intubation (TCI equilibrium) and post-intubation (maximum measurement within 5 minutes).