[Note: a full-text pdf of this 12-page article, including a glossary of pain terminology, a guide to differentiating this condition from others, and strategies for minimizing the risk, is available free at http://pain-topics.org/clinical_concepts/comments.php ]
Healthcare providers are becoming increasingly aware that ongoing opioid therapy for chronic pain might paradoxically worsen the pain in some patients – a condition called Opioid-Induced Hyperalgesia or OIH.
According to Peggy Compton, RN, PhD, author of this evidence-based review, present indications are that OIH does not arise in the majority of patients taking opioid analgesics, but when it does occur it can be difficult to manage.
Source: Pain Treatment Topics, August 20, 2008. By Compton P, http://pain-topics.org/