Evaluation of the postoperative morphine-sparing effect of oral premedicants used as pre-emptive analgesics in breast-conserving cancer surgeries: A randomised placebo-controlled trial.

Background and Aims: Breast cancer surgeries are associated with both nociceptive and neuropathic pain, requiring strong analgesics. We aimed to evaluate the postoperative morphine-sparing effect of pre-emptive oral premedication with tramadol versus pregabalin in patients undergoing breast-conserving cancer surgeries (BCCS).

Methods: This prospective, randomised, placebo-controlled trial was carried out at tertiary care centre on 90 patients undergoing BCCS randomised into three groups of 30 each. Group C received placebo, Group T received tramadol 100 mg and Group P received pregabalin 75 mg as oral premedication, 1 hour before surgery. General anaesthesia was administered. Postoperatively morphine 1 mg.h-1 through intravenous PCA was started at a visual analogue scale score ≥4. Total morphine consumption in 24 hours was calculated and its sparing effect was evaluated as the primary outcome.

Results: The median with interquartile range (IQR) of total postoperative morphine consumed in 24 hours, was found to be 22 mg (IQR 0-25.77), 15 mg (IQR 0-16) and 17.50 mg (IQR 0-19.25) in groups C, T, P respectively, (P = 0.000, 0.003, 0.060). The median duration of analgesia in group C was 5.40 hours (IQR 3.30-11.40), 11.6 hours (IQR 9.30-24.0) in group T and 8.60 hours (IQR 6.97-16.27) in group P (P value C/T = 0.000, C/P = 0.007, T/P = 0.002). The postoperative side effects were comparable.

Conclusion: Oral tramadol 100 mg and oral pregabalin 75 mg as premedication reduced the 24 hours postoperative morphine requirement as compared to placebo in BCCS. However, tramadol 100 mg provided superior analgesia for longer duration than pregabalin 75 mg and was associated with more side effects.