Currently, the investigators' patients undergoing SDR are treated for 48 hours with scheduled intravenous (IV) narcotic (continuous fentanyl infusion at 0.5-2.0 μg/kg/hour) in addition to the sedative/muscle relaxant Valium (0.2 mg/kg IV every 4 hours for 24 hours, then every 6 hours for 24 hours). The IV fentanyl, and to a lesser degree Valium, carries a real risk of hypotension and respiratory depression and requires frequent dose adjustments to achieve adequate analgesia.