Pharmacotherapy: Pharmacologic Management of Opioid-Induced Adverse Effects
Many providers hesitate to use opioid analgesics for fear of adverse effects. This philosophy can interfere with the optimal management of the person with pain. In this article, Dr. Carbonara briefly discusses the pathophysiology of selected opioid-related adverse effects and provides the clinician with practical treatment strategies to overcome them.
—Charles D. Ponte, PharmD
Opioid analgesics are effective agents for the treatment of various types of pain. Often, it is the resulting side effects of opioid use that negatively affect outcomes and the ability to continue care.1 A recent report stated that approximately 56% of patients discontinue treatment with opioid analgesics due to ineffectiveness or adverse effects.1
There is no ceiling dose for opioid agonists that may be required for pain control, but it is often the presence of adverse effects that limit the dose that can be tolerated. Adverse effects and therapeutic effects result from the binding of the opioid agonists to their various receptors throughout the body.2 Most opioid adverse effects result from binding to the receptors in the central nervous system and gastrointestinal tract. Common adverse effects seen in clinical practice include sedation, confusion, respiratory depression, nausea and vomiting, constipation, pruritis, and urinary retention.2
There are many strategies that have been recommended to limit the adverse effects of opioid therapy. The American Pain Society recommends the following options: changing the dosing regimen or route of administration of the same drug to maintain constant blood levels, instituting a different opioid, considering multi-drug or multi-modal therapy, adding another drug that counteracts the adverse effect, or changing the route of administration to minimize the drug concentration at the targeted site for the adverse effect.3 This article will focus on adjunctive strategies and provide practical information on pharmacologic recommendations for managing constipation, nausea and vomiting, sedation, and respiratory depression seen with the use of chronic opioids. Table 1 provides a summary of adjuvants for managing opioid-induced adverse effects.
Opioid-induced bowel dysfunction (OBD) results from the actions of opioids within the gastrointestinal tract.4 Constipation is the most common symptom of chronic OBD, and it can be debilitating for patients.4 Constipation results from the binding of opioids to the m?2 receptors in the gastrointestinal tract.5 This results in increased smooth muscle tone, thereby inhibiting peristalsis and the antegrade movement of stool through the gastrointestinal tract. This decrease in motility, along with reduced secretions in the gut, leads to the formation of dry, hard stools that are difficult to pass.4
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