Background and Aims: Patients undergoing breast cancer surgeries face significant postoperative pain. We aimed to compare the analgesic efficacy of plain bupivacaine and plain bupivacaine with magnesium sulphate and dexamethasone in pectoral nerve block (PECS). Methods: Sixty ASA status I and II female patients between age 18 to 60 years scheduled for unilateral modified radical mastectomy (MRM) under general anaesthesia, were enrolled in this prospective randomised double blind controlled study. All patients received USG guided
PECS block. Patients in group C were given a total of 30 cc 0.25% bupivacaine while group D received total of 30 cc 0.25% bupivacaine with 4 mg dexamethasone and group M received 150 mg of magnesium sulphate with 0.25% of bupivacaine 30cc in total. General anaesthesia was administered in a standardised manner to all three groups before giving block. The various parameters observed included duration of analgesia, VAS score, number of rescue analgesics required and any adverse effects. The primary outcome was to compare total duration of analgesia between the three groups.

Results: The mean duration of analgesia was 778.95 ± 94.735 min (13 hrs) in group D, 519.90 ± 66.607 min (9.3 hrs) in group M and 384.30 ± 49.558 min (6.4 hrs) in group C. At 12 and 24 hrs, VAS scores were significantly lower in group D as compared to group M and group C (p > 0.001). The difference in VAS scores between group M and group C at 12 and 24 hrs was not statistically significant. At 48 hrs VAS scores among the three groups were comparable.

Conclusion: In the postoperative period, the use of dexamethasone and magnesium sulphate as adjuncts to bupivacaine in PECS block results in lower VAS scores, decreased demands for rescue analgesia and prolonged duration of analgesia. The use of these adjuvants provides better patient satisfaction without causing any noticeable side effects.