Dexamethasone versus Fentanyl as Adjuvants to Intrathecal Bupivacaine Anesthesia in Cesarean Section: Impacts on Analgesia Duration and Postoperative Outcomes

Background: Effective postoperative analgesia after cesarean section is essential to facilitate early maternal recovery and reduce opioid-related side effects. Although fentanyl is commonly used as an intrathecal adjuvant to bupivacaine, concerns about adverse effects such as pruritus and nausea have prompted exploration of alternatives like dexamethasone. Objective: To compare the efficacy and safety of intrathecal dexamethasone versus fentanyl as adjuvants to 0.5% bupivacaine in spinal anesthesia for cesarean section. Methods: In this quasi-randomized clinical study, 70 women undergoing elective cesarean section were allocated to receive spinal anesthesia with bupivacaine plus either fentanyl (10–25µg; Group F) or dexamethasone (2–4mg; Group D). Hemodynamic parameters, duration of postoperative analgesia, incidence of side effects, ambulation time, and patient satisfaction were assessed using validated instruments. Results: Group D demonstrated significantly longer analgesia duration (median 5.0 h [IQR 4.0–6.0]) compared to Group F (3.0 h [IQR 2.0–4.0], p<0.001). Post-spinal systolic blood pressure and heart rate were significantly higher in the dexamethasone group but remained within physiological limits. Adverse events such as pruritus and postoperative nausea/vomiting were significantly more frequent in Group F, while back pain was reported only in Group D (20%, p=0.011). Patient satisfaction was higher in group F (p<0.001), potentially due to earlier ambulation. Conclusions: Intrathecal dexamethasone is a safe and effective adjuvant to bupivacaine in cesarean section spinal anesthesia, offering prolonged analgesia and fewer opioid-related side effects compared to fentanyl. Further randomized trials with longer follow-up and neonatal outcomes are warranted.