Ondansetron is as effective as diphenhydramine for treatment of morphine-induced
pruritus after cesarean delivery.
Author(s): Siddik-Sayyid SM, Yazbeck-Karam VG, Zahreddine BW, Adham AM, Dagher CM, Saasouh
WA, Aouad MT.
Affiliation(s): Department of Anesthesiology, American University of Beirut-Medical Center,
Beirut, Lebanon.
Publication date & source: 2010, Acta Anaesthesiol Scand. , 54(6):764-9
BACKGROUND: Subarachnoid (SA) morphine, highly effective for the management of
pain after a cesarean delivery, is associated with a significant incidence of
pruritus in up to 80% of patients. No previous study has compared the
effectiveness of ondansetron (5-HT(3) antagonist) vs. diphenhydramine (H(1)
receptor blocker) for the treatment of this side effect.
METHODS: In this randomized, double-blind study, 113 patients with a pruritus
score 3 or 4 (1=absent; 2=mild, no treatment required; 3=moderate pruritus,
treatment required; and 4=severe pruritus) after SA morphine 0.2 mg were assigned
to group ondansetron, which received 4 mg intravenously (i.v.) ondansetron, and
group diphenhydramine, which received 25 mg i.v. diphenhydramine. Patients who
continued to have pruritus > or =3, 30 min after the study drug were considered
treatment failures and were treated with naloxone 0.04 mg i.v. repeatedly, as
well as patients who relapsed. Pain scores, nausea, vomiting, and sedation were
determined before and 30 min after the study drugs were administered. Patients
were followed up for 24 h.
RESULTS: The success rate was comparable between the two groups [40/57 (70%) and
38/56 (70%), P=0.79, in group ondansetron and group diphenhydramine,
respectively]. Among the successfully treated patients, the recurrence rates of
moderate to severe pruritus were 11/40 (28%) in group ondansetron and 13/38 (35%)
in group diphenhydramine, P=0.52. The side effect profile was similar between the
two groups.
CONCLUSION: Ondansetron is as effective as diphenhydramine in relieving pruritus
caused by SA morphine in patients undergoing a cesarean delivery. However, up to
50% of patients required naloxone either for primary failure or for recurrence.
|