Affiliation:
1. Millennium Pain Center, Bloomington, IL
Abstract
Medications which bind to opioid receptors are increasingly being prescribed
for the treatment of multiple and diverse chronic painful conditions. Their use
for acute pain or terminal pain is well accepted. Their role in the long-term
treatment of chronic noncancer pain is, however, controversial for many reasons. One of the primary reasons is the well-known phenomenon of psychological addiction that can occur with the use of these medications. Abuse and
diversion of these medications is a growing problem as the availability of these
medications increases and this public health issue confounds their clinical utility. Also, the extent of their efficacy in the treatment of pain when utilized on a
chronic basis has not been definitively proven. Lastly, the role of opioids in the
treatment of chronic pain is also influenced by the fact that these potent analgesics are associated with a significant number of side effects and complications. It is these phenomena that are the focus of this review.
Common side effects of opioid administration include sedation, dizziness,
nausea, vomiting, constipation, physical dependence, tolerance, and respiratory depression. Physical dependence and addiction are clinical concerns that
may prevent proper prescribing and in turn inadequate pain management.
Less common side effects may include delayed gastric emptying, hyperalgesia, immunologic and hormonal dysfunction, muscle rigidity, and myoclonus.
The most common side effects of opioid usage are constipation (which has a
very high incidence) and nausea. These 2 side effects can be difficult to manage and frequently tolerance to them does not develop; this is especially true
for constipation. They may be severe enough to require opioid discontinuation,
and contribute to under-dosing and inadequate analgesia. Several clinical trials are underway to identify adjunct therapies that may mitigate these side effects. Switching opioids and/or routes of administration may also provide benefits for patients. Proper patient screening, education, and preemptive treatment
of potential side effects may aid in maximizing effectiveness while reducing the
severity of side effects and adverse events. Opioids can be considered broad
spectrum analgesic agents, affecting a wide number of organ systems and influencing a large number of body functions.
Key words: Opioids, morphine, methadone, fentsnyl, oxycodone, hydrocodone, xymorphone, codeine, adverse events, narcotics, side effects, constipation, sedation, hearing loss, tolerance, addiction, hyperalgesia
Publisher
American Society of Interventional Pain Physicians
Subject
Anesthesiology and Pain Medicine