Analgesic effect of intra-articular neostigmine after operative knee arthroscopy comparative study of neostigmine, tenoxicam, morphine and placebo

ABSTRACT

This study was designed to compare the postoperative peripheral analgesic effect of intra-articular [IA] neostigmine, tenoxicam, morphine and placebo. The study included forty unpremedicated adult patients with ASA status 1 or 2, scheduled for operative knee arthroscopy under general anaesthesia. Patients were randomly allocated into four equal groups [each 10 patients] Group A received 500 micro g neostigmine in 30 ml saline IA, group B received 20 mg tenoxicam in 30 ml saline IA. group C received 2 mg morphine in 30 ml saline IA, and group D received 30 ml saline [placebo control group]. Postoperative pain was assessed using a 10-cm visual analogue scale [VAS] at 1.4,8,24 and 48 hours and at time of dem and ing analgesia. Time to first analgesic administration and the total amount of analgesic consumption over 48 hrs were compared in the four groups. There was a significant reduction in VAS in the neostigmine group at 1,4 hrs compared to tenoxicam. morphine or saline groups, and at 8, 24 hrs compared to morphine and saline groups. At 48 hrs no intergroup difference was detected. Time to first analgesic administration was significantly longer in the neostigmine group, also, the total amount of analgesic consumption per 48 hrs was significantly less in the neostigmine group in comparison to tenoxicam. morphine or saline groups. It can be concluded that neostigmine induces effective postoperative analgesia at peripheral sites of about 8-9 hrs, provided no atropine was given, with no side effects. Analgesic efficacy of intra-articular neostigmine is better than either tenoxicam or morphine given intra-articuLarly