Prophylactic Effect of Ondansetron for Intrathecal Fentanyl-Induced Pruritus


S . Saeed Jahanbakhsh 1 , Mehdi Fathi 2 , * , Saha Bazyar 2


2 Department of Anesthesia, Cancer Surgery Research Center, Mashhad University of Medical Sciences, Mashhad, Iran

How to Cite: Jahanbakhsh S . S, Fathi M, Bazyar S. Prophylactic Effect of Ondansetron for Intrathecal Fentanyl-Induced Pruritus, Zahedan J Res Med Sci. 2013 ; 16(1):8-12.


Zahedan Journal of Research in Medical Sciences: 16 (1); 8-12
Published Online: April 06, 2013
Article Type: Research Article
Received: July 02, 2012
Accepted: September 16, 2012


Background: Using opioids along with local analgesic increase anesthesia duration and provide appropriate postoperative analgesia. However, intrathecal injection of opioids is associated with upsetting side effects including pruritus. Ondansetron (5-HT3 receptor agonist) has anti-pruritus effects. Therefore, we conducted a double blind randomized case-control study to evaluate prophylactic effects of ondansetron for preventing intrathecal fentanyl-induced pruritus.

Patients and Methods: Two hundred seven patients with ASA status I, II or III, who were candidate for pelvic or lower extremity surgery with spinal anesthesia (SA) using bupivacaine hyperbaric (10-15 mg) and fentanyl (25 µg) were included in the study. Patients were randomly assigned to two groups of case (ondansetron 8 mg IV) and control (4 ml normal saline IV). Patients’ hemodynamic indexes and side effects were evaluated at 5, 10, 30, 60 minutes and then hourly up to 6 hours after SA. Pruritus presence, degree, and site were evaluated after two and six hours. Data were analyzed using Kolmogorov-Smirnov test, student t-test, Mann–Whitney U, χ2, Fisher exact test, and Spearman linear correlation coefficient.

Results: The pruritus incidence was 60% in control and 34% in case group. Severe pruritus was observed in 18% of control group and 6% of case group. Ninety four percent of patients with pruritus in control group expressed it in above T6 dermatomes and 74% of patients with pruritus in case group had pruritus in T6-L1 dermatomes. The incidence of pruritus in L1-lower dermatomes was similar in two groups. Headache and nausea after anesthesia were more common in control group (p=0.035).

Conclusions: Ondansetron decrease incidence and degree of intrathecal fentanyl-induced pruritus. This reduction was more significant around injection area T6-L1 dermatomes. Ondansetron injection does not influence systolic blood pressure, duration of anesthesia and analgesia, and does not induced urinary retention and back pain.


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