"New Research Suggests Oxycodone May be More Effective Than Morphine in Treatment of Visceral Pain"

SYDNEY, AUSTRALIA -- August 25, 2005 --
A new experimental study in healthy volunteers suggesting that the use of oxycodone, an established, modern synthetic opioid compound, may be better at treating visceral pain than morphine, has been presented today at the IASP 11th World Congress on Pain, in Sydney, Australia
(1). The results, consistent with clinical experience, show for the first time significant differences between oxycodone and morphine in the treatment of visceral pain, suggesting the compound may be used as a treatment for this type of pain. "Visceral pain is one of the most challenging symptoms of gastroenterology," explained Professor Jens Arendt-Nielsen, Department of Gastroenterolgy, Aalborg University, Denmark. "This study is the first time that analgesics have been assessed using a multi-modal, multi-tissue pain assessment approach, providing an opportunity to assess the differentiated effect of new and existing drugs on specific tissues and specific pain modalities." To collect the study results, visceral stimuli were applied to healthy volunteers in the oesophagus via a probe mounted on a balloon. The unique device was used to apply mechanical, heat pain and electrical pain stimuli. For stimulation in skin and muscles, electrodes, a pressure algometer and a 'thermo tester' were used. 24 subjects (12 women and 12 men) participated in this double blind, randomised experiment. After a baseline recording of the experimental pain, oxycodone (15 mg), morphine (30 mg) or placebo were randomly administered. Participants' pain responses were assessed in relation to the different pain stimuli, tested at baseline, 30, 60 and 90 minutes. Results from the study showed that both opioids had significantly better analgesic effect than placebo (all P values<.001). Most interesting, the opioids were equally effective in all tissues but the viscera, where oxycodone was shown to be more effective (P<.001). Visceral pain, classified as pain affecting 'soft' organs and body tissues, or viscera, is an extremely common condition that can be severely debilitating. Most people will have experienced this form of pain, which can range from mild discomfort (e.g. that associated with indigestion or mild gastro-oesophageal reflux) to excruciating agony (e.g. renal colic, severe irritable bowel syndrome etc). For many patients, visceral pain can be part of a complex syndrome involving pain signals from a number of organs and tissues
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