Oxycodone vs. fentanyl in the treatment of early post-operative pain after laparoscopic cholecystectomy: a randomised double-blind study

BACKGROUND: It has been suggested that oxycodone is superior to other opioids in the treatment of visceral pain. We therefore compared the effect of intravenous (i.v.) oxycodone and i.v. fentanyl on post-operative abdominal (visceral) pain after outpatient laparoscopic cholecystectomy.

METHODS: Seventy-eight patients were randomised to intra- and post-operative pain treatment with either oxycodone (n=39) or fentanyl (n=39). The patients received 10 mg oxycodone/100 microg fentanyl at the end of anaesthesia. In the post-anaesthetic care unit (PACU), 5 mg oxycodone/50 microg fentanyl was administered to patients with moderate pain [3-5 on a numeric rating scale (NRS)], and 10 mg oxycodone/100 microg fentanyl was administered to patients with severe pain (>5 on an NRS). The following measures were recorded: intensity of pain at arrival, after 30, 60 and 90 min and at discharge from the PACU; total consumption of oxycodone/fentanyl; nausea; vomiting; sedation and pressure tolerance thresholds.

RESULTS: The median intra- and post-operative consumption of oxycodone was 15 mg (range: 10-40 mg) and the consumption of fentanyl was 200 microg (range: 100-500 microg). The intensity of abdominal pain was significantly lower in the oxycodone group at arrival (P<0.05), after 30, 60 and 90 min, and at discharge from the PACU (P<0.01). There was a strong tendency towards more side effects with oxycodone.

CONCLUSIONS: Oxycodone provided better analgesia but also more side effects, suggesting that the doses used in the present study may not be equipotent.