A comparison of oxycodone and fentanyl in the management of early postoperative pain and for patient-controlled analgesia after total abdominal hysterectomy

ABSTRACT

BACKGROUND: Although oxycodone has been known to be superior to other opioids in postoperative care, few studies have compared its analgesic potency with that of fentanyl. We therefore examined these two drugs in terms of their dose requirements, effects on pain intensity, time needed for relief of pain, and side effects after surgery. METHODS: We enrolled 56 healthy women scheduled for total abdominal hysterectomy and randomly allocated them to either oxycodone or fentanyl. The opioids were administered to the two groups 10 minutes before the end of the operation. In the post-anesthesia care unit (PACU) after surgery, a visual analog scale (VAS) was used to assess the patients' pain every 10 minutes Whenever pain control was required, a bolus of the same dose of the respective drugs was repeated at 10-minute intervals. Patient-controlled analgesia (PCA) was used to manage postoperative pain. After the patient arrived on the ward, pain scores were recorded at once and then 1, 2, 3, and 24 hours thereafter. RESULTS: During the hour spent in the PACU, fewer patients in the oxycodone group required the opioid, and the time needed to achieve pain relief was shorter with oxycodone than with fentanyl. Moreover, postoperative VAS levels were significantly lower in the oxycodone group both in the PACU and on the ward (over a 24-hours period). There were no significant differences in side effects between the patients given oxycodone and those given fentanyl. CONCLUSIONS: Oxycodone was more effective than fentanyl when administered on the basis of the recommended dose ratio (1 100). Although further evaluation is needed to investigate the optimal dose ratio, we would recommend a higher conversion factor (1 62).