The effect of addition of ultra-low dose of naloxone to fentanyl-bupivacaine mixture on the incidence of pruritis after spinal anesthesia for cesarean delivery: Randomized clinical study.

Background And Aims: The use of intrathecal opioids is associated with high risk of pruritis and this may be decreased by adding a low dose of naloxone. This study evaluated the effect of the addition of 20 μg of naloxone to fentanyl-bupivacaine mixture on the incidence of pruritis in pregnant females scheduled for cesarean section (CS).

Material And Methods: Eighty pregnant patients scheduled for CS under spinal anesthesia were randomized to receive either 10 mg of 0.5% hyperbaric bupivacaine (2 ml) plus 25 μg fentanyl (group F) or 10 mg of 0.5% hyperbaric bupivacaine (2 ml) plus 25 μg fentanyl and 20 μg naloxone (group FN). The incidence, onset, duration, site, and severity of pruritis were measured. Furthermore, the postoperative numerical rating scale (NRS) score, the total tramadol rescue analgesia, and the time for the first request of rescue analgesia were recorded.

Results: Compared to the F group, the FN group showed a significant decrease in the incidence of pruritis ( = 0.022), prolongation of the onset of pruritis ( = 0.006), shortening of the duration of pruritis ( = 0.029), and decrease in the severity of pruritis ( = 0.039). Furthermore, the postoperative pain score, the rescue analgesic consumption, and the time for the first request of rescue analgesia were comparable between the two groups ( > 0.05).

Conclusions: The addition of an ultra-low dose of naloxone (20 μg) to fentanyl-bupivacaine mixture in spinal anesthesia for pregnant females scheduled for CS significantly reduced the incidence of pruritis without having a significant effect on the postoperative analgesia.