RESUMEN
OBJECTIVES: To compare the analgesic efficacy of intrathecal Ketamine and fentanyl added to bupivacaine in patients undergoing cesarean section. METHODS: Ninety patients 18-40 years old were recruited in a prospective double-blinded, randomized way. Spinal anesthesia was performed in the three groups by using bupivacaine 10mg combined with 0.1mg/kg ketamine in group K, bupivacaine 10mg combined with 25 µg fentanyl in group F and bupivacaine 10mg combined 0.5 ml distilled water in group P. The time to first analgesic request, analgesic requirement in the first 24 hours after surgery, sensory and motor blockade onset time, duration of sensory and motor blockade, the incidence of adverse effects were recorded. RESULTS: The mean time to first analgesic request was longer in group K (296.80 ± 32.46) compared to group F (277.87 ± 94.25) and group P (235.43 ± 22.35). The difference between group K and F (P = 0.504) was not significant but the difference between group K and group P (P <0.001) and group F and group P (P = 0.042) was significant. CONCLUSION: Addition of ketamine or fentanyl to spinal bupivacaine were equally effective in pain control after cesarean section and therefore, based on the specific conditions of patients, ketamine at concentrations mentioned earlier, could be a proper alternative to achieve postoperative analgesia