Opioids in non-cancer pain: Pharmacokinetic study supports BID oral administration of Oxytrex™ in a chronic model of pain

Abstract

Purpose was to evaluate the quality of the block and the duration of postoperative analgesia when ultra-low-dose of naloxone added to fentanyl and lidocaine for peribulbar anesthesia.Sixty adult patients of both sexes, ASA I and II scheduled for open globe cataract surgery in the Ophthalmology Department Tanta University Hospital were included in this randomized prospective clinical trial.The patients were randomized into 2 groups (30 patients each). Group I: patients received 50 μg fentanyl and lidocaine 2% with hyaluronidase 15 IU/ml. Group II: patients received 100 ηg naloxone, 50 μg fentanyl and lidocaine 2% with hyaluronidase 15 IU/ml.Total akinesia was scored every 2 min till the best akinesia score. Onset, best akinesia score, total injected volume, number of patients needed supplemental injection, time of first request for analgesia and, any complication were recorded. Pain was assessed during and after surgery at 30, 60, 90 min, 2, 3, 4, 6 and 8 h postoperatively, using Visual Analogue Score; 0 = no pain, to 10 = maximum pain.The time to first rescue analgesic was significantly longer in group II (7.73 ± 0.98) than group I (4.30 ± 0.47). The IOP was increased significantly at 2 min post-injection then, it became insignificant at 10 min postinjection compared to the preinjection values in both groups. There were few minor complications with no significant difference between groups.Addition of ultra-low-dose naloxone to fentanyl and lidocaine for peribulbar anesthesia prolongs the duration of postoperative analgesia without increasing the adverse effects.