Eight studies (approximately 1,861 participants) were included in the review; one study was a follow-on trial and included some of the same patients as an earlier included study.
In the two studies of post-operative pain relief, oxymorphone immediate release was significantly more effective than placebo or oxycodone immediate release, but the doses of oxymorphone and oxycodone given were not equivalent.
In one study of post-operative pain relief and five of chronic pain, oxymorphone extended release was significantly more effective than placebo and was equivalent to controlled-release oxycodone or morphine.
The adverse event profile of oxymorphone was comparable with those of oxycodone or morphine.
Unpublished data from the manufacturer found no difference in efficacy according to age, but the side effects of dizziness, somnolence, nausea and confusion were more common in older (≥65 years) patients than in younger patients.