Pharmacotherapy Newsletter

Volume 1, Issue 18, 05/18/2009

Question

What is the mechanism by which opioid agonists (e.g., hydromorphone, morphine, oxycodone) reduce pain transmission in the central nervous system?

Answer

Opioid analgesics have been used for decades for the management of both acute and chronic pain.  Unfortunately, many patients do not receive adequate treatment for their pain and thus, are left to suffer.^1-3  For example, the SUPPORT investigators found that 50% of seriously ill hospitalized patients reported pain with approximately 15% of patients reporting moderate to extremely severe pain at least half of the time and approximately 15% of those were dissatisfied with their pain control.²  This is one of many studies that have documented the need for better pain management strategies in community settings, hospitals and long-term care facilities.  In order to effectively manage acute and chronic pain, the clinician must not only recognize the various pharmacotherapeutic options for the different types of pain, but understand how they work to treat pain.  When clinicians say that opioids reduce the transmission of pain, what does that actually mean? How do opioids actually modify pain?