title: Prophylactic administration of ondansetron in prevention of intrathecal morphine-induced pruritus and post-operative nausea and vomiting in patients undergoing caesarean section.
abstract: BACKGROUND
  Intrathecal morphine is commonly used for post caesarean analgesia. However, their use is frequently associated with the incidence of troublesome side effects such as nausea, vomiting and pruritus. Various mechanisms have been postulated for the opioid-induced pruritus, with a variety of medications with different mechanisms of actions formulated for the prevention and treatment. But, the results are inconsistent and hence the prevention and treatment of opioid-induced pruritus still remains a challenge. Ondansetron which is antiemetic, non-sedative and has no antianalgesic effect is an antagonist to 5-HT3 receptor, the receptor with which opioids interacts and imparts its effects. Ondansetron, thus, would be an attractive treatment strategy for both opioid-induced pruritus and post-operative nausea and vomiting.
  
  
  METHODS
  After the approval from institutional review committee and written consent received from the patient, 50 healthy parturients of ASA I and II physical status undergoing caesarean section under spinal anaesthesia were enrolled for the study. They were randomly categorized into placebo group (2 ml normal saline) and treatment group (2 ml of 4 mg ondansetron), each group containing 25 patients. Pruritus and post-operative nausea and vomiting scores were recorded up to 24 hours after the administration of intrathecal morphine. Statistical analysis was performed using chi-square test.
  
  
  RESULTS
  The incidence, severity and necessity of treatment for pruritus in the treatment group was significantly reduced compared to the placebo group (16% vs 88%). Similarly, the risk of post-operative nausea and vomiting in the treatment group was less compared to the placebo group (8% vs 56%).
  
  
  CONCLUSIONS
  Prophylactic administration of ondansetron to parturients receiving intrathecal morphine for post-operative analgesia provides a significant reduction of intrathecal morphine-induced pruritus and nausea and vomiting.
  
  
  BACKGROUND
  CTRI/2015/01/005362 registered on 07/01/2015 in Clinical Trials Registry-India (ctri.nic.in).
authors.affiliation: Department of Anaesthesia and Critical Care, KIST Medical College, Imadol, Lalitpur, Nepal. dr.koju@gmail.com.|Previously, Department of Anaesthesia and Critical Care, Patan Hospital, Patan, Lalitpur, Nepal. dr.koju@gmail.com.
authors.forename: Ram Bhakta
authors.initials: RB
authors.lastname: Koju
authors.affiliation: Department of Obstetrics and Gynaecology, KIST Medical College, Imadol, Lalitpur, Nepal. drbandanamd@gmail.com.
authors.forename: Bandana Sharma
authors.initials: BS
authors.lastname: Gurung
authors.affiliation: Department of Biochemistry, KIST Medical College, Imadol, Lalitpur, Nepal. theyashad@gmail.com.
authors.forename: Yashad
authors.initials: Y
authors.lastname: Dongol
mesh_terms: D000328:Adult; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000009:adverse effects*; D000932:Antiemetics / Q000008:administration & dosage*; D002585:Cesarean Section / Q000009:adverse effects; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D009020:Morphine / Q000008:administration & dosage / Q000009:adverse effects*; D017294:Ondansetron / Q000008:administration & dosage*; D020250:Postoperative Nausea and Vomiting / Q000517:prevention & control*; D011247:Pregnancy; D011446:Prospective Studies; D011537:Pruritus / Q000139:chemically induced / Q000517:prevention & control*
chemical_list: D000701:Analgesics, Opioid; D000932:Antiemetics; D017294:Ondansetron; D009020:Morphine