A randomized controlled trial of pentazocine versus ondansetron for the treatment of intrathecal morphine-induced pruritus in patients undergoing cesarean delivery.
BACKGROUND
Ondansetron is effective for the treatment of intrathecal morphine-induced pruritus. There is evidence that kappa-opioid receptor agonists have antipruritic activity. Pentazocine is an agonist of kappa-opioid receptors and partial agonist at mu-opioid receptors. We therefore performed a randomized, double-blind trial to compare the efficacy of pentazocine and ondansetron for the treatment of pruritus associated with intrathecal injection of morphine in patients undergoing cesarean delivery.


METHODS
Two hundred eight parturients who developed moderate to severe pruritus after the administration of intrathecal morphine were randomly allocated to 2 groups: IV pentazocine 15 mg (n = 104) and IV ondansetron 4 mg (n = 104). The successful treatment of pruritus (no or mild pruritus) and other adverse effects were determined 15 min after study drug administration, and patients were observed for recurrence of pruritus for 4 h.


RESULTS
The treatment success rate at 15 min was higher in the pentazocine group (96.1%) than in the ondansetron group (80.8%) (95% confidence interval of difference: 7.0%, 23.8%; P = 0.001). The recurrence rate of moderate to severe pruritus within 4 h after treatment in the pentazocine group (12.0%) was lower than in the ondansetron group (32.1%) (P = 0.001). There were no significant differences between groups in nausea/vomiting, sedation, shivering, pain scores, and pain at injection site. No respiratory depression was observed.


CONCLUSIONS
Pentazocine 15 mg is superior to ondansetron 4 mg for the treatment of intrathecal morphine-induced pruritus and has a lower recurrence rate. The side effects after treatment are mild.
Program in Clinical Epidemiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
Decha
D
Tamdee
Somrat
S
Charuluxananan
Yodying
Y
Punjasawadwong
Chamaiporn
C
Tawichasri
Jayanton
J
Patumanond
Pin
P
Sriprajittichai
D000328:Adult; D016362:Analgesia, Obstetrical / Q000009:adverse effects*; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use*; D000982:Antipruritics / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D002585:Cesarean Section; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D007278:Injections, Spinal; D009020:Morphine / Q000008:administration & dosage / Q000009:adverse effects*; D017294:Ondansetron / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D010423:Pentazocine / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D011247:Pregnancy; D011446:Prospective Studies; D011537:Pruritus / Q000139:chemically induced / Q000188:drug therapy*; D012008:Recurrence; D012720:Severity of Illness Index; D016896:Treatment Outcome
D000701:Analgesics, Opioid; D000982:Antipruritics; D017294:Ondansetron; D009020:Morphine; D010423:Pentazocine