Pilot double-blinded study to assess efficacy and tolerability of morphine sulphate oral solution (Oramorph®) given preoperatively as add-on therapy within a multimodal postoperative pain approach in patients undergoing laparoscopic cholecystectomy

Abstract

Background: This study aims at investigating the effect of a single pre-operative oral administration of morphine sulphate (Oramorph®) on pain after laparoscopic cholecystectomy (LC).

Methods: Forty-one ASA I-III patients, aged 18-65 years, undergoing LC were randomly, double-blindly allocated to treatment (N.=20, 30mg Oramorph®, group M) or placebo (N.=21, group P). General anesthesia was maintained with propofol and remifentanil. All patients received ketamine 0.2 mg/kg iv at induction, intraoperative ketorolac 30mg iv and tramadol postoperatively (iv PCA: bolus 50 mg, lock-out 30 min, max 100 mg/4 hours). Numerical rating scale for pain (NRS), White's fast track and PADSS scores, tramadol consumption and adverse events were recorded for the first 24h. All patients underwent State Trait Anxiety Inventory (STAI) and Mini Mental State Examination (MMSE).

Results: Anthropometric characteristics, MMSE, STAI, ASA status, NRS rest, White's and PADDS scores, PONV incidence were similar. Group M showed significantly lower NRS on movement during the first 3 hours after awakening. Cumulative tramadol consumption was lower in group M than in group P (185±142 mg versus 263±199 mg, P=0.199).

Conclusion: Within a multimodal approach, a single preoperative oral administration of 30 mg of morphine sulphate in patients undergoing LC did not improve pain at rest, but improved NRS on movement during the first 3 hours after awakening. Group P required a higher mean dose of tramadol compared to Group M, although not significantly. The safety profile of Oramorph® allowed fast extubation and awakening times as well as prompt home discharge within 6 hours from surgery.