Analgesic Efficacy of IV Dexamethasone vs Intrathecal Dexamethasone as an Adjuvant to Spinal Anesthesia in Lower Abdominal Surgeries

Background: Dexamethasone, an adjuvant to spinal anesthesia, has been explored for its potential to prolong sensory block duration. However, the comparative efficacy of intravenous (IV) versus intrathecal administration remains unclear. Objective: To compare the analgesic efficacy and duration of sensory block between IV dexamethasone and intrathecal dexamethasone as adjuvants to spinal anesthesia in lower abdominal surgeries. Patients and Methods: This interventional clinical trial included 90 patients undergoing lower abdominal surgeries, randomized into two equal groups: Group IT (intrathecal dexamethasone 4 mg + bupivacaine) and Group IV (IV dexamethasone 8 mg + bupivacaine). The primary outcome was the duration of sensory block. Secondary outcomes included time to first rescue analgesia, total rescue analgesia, VAS scores, and incidence of complications. Results: The onset of sensory block was marginally faster in Group IV (28 ± 4 minutes) compared to Group IT (29 ± 3 minutes) (P = 0.046). However, Group IT demonstrated a significantly longer duration of sensory block (177 ± 17 minutes) versus Group IV (120 ± 16 minutes) (P < 0.001). Group IT also exhibited a longer time to first rescue analgesia (340 ± 27 minutes vs. 255 ± 27 minutes, P < 0.001) and lower VAS scores at 2, 4, and 24 hours postoperatively (P < 0.001). Conclusion: Intrathecal dexamethasone significantly prolongs the duration of sensory block and analgesia compared to IV dexamethasone when used as an adjuvant to spinal anesthesia in lower abdominal surgeries. Both routes of administration were comparable in terms of safety.