Unbranded drug molecules are produced after the patent of a given drug has expired. Unbranded molecules of Remifentanil have been marketed in Colombia, and several reports by anesthesiologist indicate that there are differences in the physiologic response of patients to these molecules. The investigators hypothesized that unbranded molecules of remifentanil require higher doses to obtain desired physiological responses as compared to the branded molecule.

Introduction. Several remifentanil products are commercialized in Colombia while these have never been compared in a clinical setting.

Objective. The aim of this study was to investigate the pharmacodynamic profile of the innovative molecule of remifentanil (group O = Ultiva®) and two unbranded molecules (group A = Remifentanil Laboratorios Chalver de Colombia S.A. and group B = Fada Remifentanilo) registered in Colombia.

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).

Inclusion Criteria:

• Patients requiring orotracheal intubation
• 18-50 years old
• Body mass index <31 kg/m2
• Written informed consent

Exclusion Criteria:

• Pregnancy
• Risk of difficult airway
• History of opioid use