Objective: Gabapentin has an antipruritus effect, which its efficacy in reducing pruritus induced by intrathecal morphine has
not been well documented. The purpose of the present study was to know if a single smaller dose of gabapentin could decrease
the intrathecal morphine-induced pruritus.

Material and Method: One hundred sixty eight patients from the 180 recruited patients fulfilled the trial requirement and were
scheduled for orthopedic surgery under spinal anesthesia using 0.5% isobaric bupivacaine and 0.2 mg preservative-free
morphine. The patients were divided into two groups, each of 84 subjects and received either gabapentin 600 mg or a placebo,
two hours preoperatively, in a prospective, randomized, double-blind, placebo-controlled trial. The pruritus was evaluated
at 1, 2, 3, 4, 6, 9, 12 and 24 hours after intrathecal morphine administration. Adverse events were noted.

Results: The overall incidence of pruritus was not significantly different between the two groups while the incidence and
severity of pruritus was significantly decreased in the gabapentin group at four hours after intrathecal morphine injection
(18 of 84 subjects, 21.4% vs. 35 of 84 subjects, 41.7%; p = 0.008 and 0.045 respectively). The urinary retention was
significantly higher in the study group compared to the placebo group (50.0% (42 of 84 subjects) vs. 33.3% (28 of 84 subjects)
p = 0.042).

Conclusion: Preoperative gabapentin 600 mg did not significantly reduce the postoperative intrathecal morphine-induced
pruritus.

Keywords: Gabapentin, Prophylaxis, Intrathecal morphine-induced pruritus, Orthopedic surgery