Ondansetron's Opposite Effect on Postoperative Analgesia of Acetaminophen
Condition: Postoperative Pain
MeSH terms: Pain, Postoperative
Study type: Interventional
Phase: Phase 4

Summary: 
      The purpose of the study is to determine whether the effect of ondansetron on the analgesic
      effect of acetaminophen. Because 5HT3 blockers prevent the analgesic effects of acetaminophen
      and also reduce opioid consumption
    

Detailed description: 
      The investigators enrolled 80 American Society of Anesthesiologists Physical Status I-II
      women 18-80 years old scheduled for hysterectomy under general anesthesia over the course of
      a year. The study will be restricted hysterectomies with horizontal abdominal skin incision
      who will be able to operate a patient-controlled analgesia (PCA) device.

      Participating women will be premedicated with 1-2 mg intravenous (IV) midazolam per
      preference of the attending anesthesiologist.

      Anesthesia will be induced with propofol (2 mg/kg IV); intubation will be facilitated by
      rocuronium (0.6 mg/kg IV); and anesthesia will be maintained by sevoflurane in combination
      with nitrous oxide 50% in oxygen. Fentanyl, 2 µg/kg intravenous will be given 3-5 min before
      the surgical incision.

      After endotracheal intubation, all patients' lungs will be mechanically ventilated to
      maintain the end-expiratory carbon dioxide values between 34 and 36 mmHg.

      A Pfannenstiel approach will be used in each woman, and the same surgeon will be conducted
      all operations.

      Randomization will be web-based and out of the control of any investigator. The web system
      will be accessed by the anesthesia resident at the induction. Drugs will be covered by opaque
      plastic to keep the surgical team and anesthesiologists blinded to treatment.

      Both groups patients will be received 1 g acetaminophen in 100 ml saline given every 6 hours
      starting with the skin closure for 24 hours, an amount generally regarded as safe.

        1. Group I patients will be received '8 mg ondansetron hydrochloride'

        2. Group II patients will be received '2 ml saline' Both of them will be applied in a 100
           ml saline bag at the same time with the skin closure.

      After return of spontaneous ventilation and tracheal extubation, patients will be transferred
      to the post anesthesia care unit (PACU).

      Patients were connected to a patient-controlled analgesia (PCA) device and postoperative
      analgesia will be provided using 20-mg intravenous bolus injections of tramadol at a lockout
      interval of 15 min and with a maximum 4-h limit of 150 mg. The PCA device will be
      discontinued when the patient made no demands for the opioid analgesic in the preceding 4-h
      interval or at a maximum of 24 hours after surgery.

        -  heart rate

        -  systolic arterial blood pressures

        -  diastolic arterial blood pressures

        -  mean arterial blood pressures

        -  oxygen saturation

        -  respiratory rate

        -  visual analogue scales while sitting and laying

        -  tramadol consumption

        -  additive analgesics

        -  complications

        -  postoperative nausea and vomiting scores

        -  antiemetic use will be assessed at PACU, 1th. hour, 4th hour, 8th hour, 12th hour, 16th
           hour, 20th hour and 24th hour.

        -  Pain satisfaction scale

        -  ambulation time

        -  first flatus time

        -  oral intake time

        -  Hospital anxiety and depression scale

      When pain scores were VAS ≥5, then as a rescue analgesics 75 mg diclofenac Na intramuscularly
      will be given. If systolic arterial pressure (SAP) will be <90 mmHg or mean arterial pressure
      will be <50 mmHg, 5 mg intravenous ephedrine HCl will be given. If the heart rate will be <50
      beats/minute, 0.5 mg atropine sulfate intravenous will be given. When patients sustained
      nausea or vomiting lasting longer than 5 minutes, metoclopramide (10 mg intravenously) will
      be given.
    

Intervention name(s): ondansetron; isotonic
Intervention type(s): Drug; Drug
Intervention description(s): 8 mg intravenous in the skin closure; 8 mg intravenous in the skin closure
Other intervention name(s): Zofran
Intervention MeSH terms: Ondansetron
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Care Provider, Investigator)
Primary purpose: Treatment
Keywords: Acetaminophen, ondansetron