BACKGROUND The imidazobenzodiazepine Ro 15-1788 has been shown to block the central effects of benzodiazepines without severe side effects in animals studies and human volunteers. Benzodiazepine premedication and benzodiazepine/opioid combinations are often used in anesthesiology. A prolonged benzodiazepine action in combination with narcotics can cause problems in the postoperative period such as respiratory depression or aspiration of gastric contents due to reduced vigilance. Therefore, a reversal of the central effects of benzodiazepines can be of advantage postoperatively. This study was designed to compare the efficacy of Ro 15-1788 and placebo in reversing the central effects of flunitrazepam used to induce and maintain general anesthesia. METHODS METHODS double blind, parallel groups, randomized, placebo-controlled study. 60 patients of both sexes aged 20-65 years, ASA class I-II, who were to undergo elective surgery under general anesthesia with an estimated duration of 90-150 min. Study procedure: Evening premedication: 1-2 mg flunitrazepam orally. Morning premedication: 7.5 mg midazolam orally. Monitoring: blood pressure, heart rate, and ECG continuously. Induction of anesthesia: 0.2 mg fentanyl, 0.03-0.04 mg/kg flunitrazepam, 0.1 mg/kg pancuronium. Endotracheal intubation, mechanical ventilation. Maintenance of anesthesia: N2O/O2 = 2:1, fentanyl, pancuronium, and flunitrazepam depending on clinical response. At the end of surgery and after decurarization (neostigmine 2.5 mg and atropine 0.5 mg) and oxygenation the patients were extubated. Now Ro 15-1788 or placebo in a 5% glucose solution (in the case of Ro 15-1788: 1 ml = 0.1 mg active drug) were administered.(ABSTRACT TRUNCATED AT 250 WORDS)