Background: Awareness is a common problem of general anesthesia. The overall prevalence of awareness was reported 1-10%. The present study was conducted to determine the effects of neurolept anesthesia on awareness.

Materials and methods: This double blind clinical trial was performed on sixty 25-40-year old individuals undertaking spinal surgery. All of whom belonged to class I-ASA. Patients received 10 mg of Diazepam over the night before operation and 7ml/kg of ringer solution was administered in the operating room. For the first group (Group A) neurolept anesthesia started with induction (talamonale 0.1ml/kg, thiopental 5mg/kg, and pancuronium 0.1mg/kg), maintained with N₂O-fentanyl (50 μ g/30 min). For the second group (Group B) induction was started with fentanyl 1.5μg/kg, thiopenthal 5mg/kg, pancuronioum 0.1mg/kg) and maintained with halothane 0.6%, N₂O-fentanyl 50μg/30 min. A tape player was used during the procedure and patient’s awareness was measured using the pain sensation and music recall following the procedure in recovery room and 24 hour after anesthesia.

Results: Voice was heard by 10 and 3.3% of patients in the neurolept and control group, respectively (NS). Type of anesthesia had no effect on blood pressure and heart rate.

Conclusion: Neurolept anesthesia accompanied by minor changes in patients’ awareness, thus this can be safely used as a safe technique with more advantage in poor risk patients and those who need wake up test during surgery.