Background and objectives: The inhalational anesthetic isoflurane is widely used in general anesthetics. Its mechanism of action involves interaction with the receptor of gamma-amino butyric acid (GABA), which is also the binding site for benzodiazepines. Flumazenil, benzodiazepine antagonist, reverses the effects of these drugs in GABA receptors and could therefore also reverse the effect of isoflurane. In anesthesia practice, extubation and early anesthetic recovery reduce morbidity and incidence of complications. The objective of this trial is to determine whether the use of flumazenil may contribute to faster recovery from anesthesia. Methods: 40 patients scheduled to undergo general anesthesia with isoflurane were enrolled in this prospective, double-blind, randomized trial. Patients were randomized to receive, at the end of anesthesia, flumazenil or placebo as allocated into two groups. The anesthetic technique was standardized. The groups were compared concerning values of Cerebral State Index (CSI), heart rate, blood pressure and oxygen saturation from the application of flumazenil or placebo until 30 minutes after injection. Data regarding time to extubation, time to reach ten points in the Aldrete-Kroulic score (AK = 10) and Vigilance score (VS = 10) was also collected. ANOVA test was applied to analyze the results, considering p <0.05.

Inclusion Criteria:

• patients scheduled to surgeries with general anesthesia,
• healthy or with minor diseases completely controlled by regular use of medications (ASA I or II according to the classification of physical state by the American Society of Anesthesiologists).

Exclusion Criteria:

• patients with past of chronic use of benzodiazepines and/or illicit drugs,
• seizures or panic disorder.