Title: Fast Fact and Concept #57: Neuroexcitatory Effects of Opioids: Patient Assessment
Author(s): Robin Wilson; David E. Weissman
Everyone recognizes the common opioid side effects: constipation, nausea, pruritis, and urinary retention. Less well appreciated are the neuroexcitatory effects, commonly seen among patients on chronic opioids. Among these, myoclonus is typically the herald symptom. Myoclonus may occur in patients on chronic therapy with most opioids including morphine, hydromorphone, fentanyl, meperidine, and sufentanil. Higher doses more frequently result in myoclonus, but the dose relationship is variable. Myoclonus can occur with all routes of administration. Current research implicates the 3-glucuronide opioid metabolites as the most likely cause of neuroexcitatory side effects. Co-morbid factors including renal failure, electrolyte disturbances, and dehydration can also contribute.
Myoclonus, the uncontrollable twitching and jerking of muscles or muscle groups, usually occurs in the extremities, starting with only an occasional random jerking movement; a patient's spouse may be the first to recognize this symptom. With continued administration, the jerking may increase in frequency; at the extreme, there is constant jerking of random muscle groups in all extremities. As myoclonus worsens, patients may develop other neuroexcitatory signs: hyperalgesia (increased sensitivity to noxious stimuli), delirium with hallucinations, and eventually, grand mal seizures. Well meaning clinicians may misinterpret the hyperalgesia as an increased need for opioid, leading to a vicious cycle of increasing dose, increasing hyperalgesia, increasing dose, worsening delirium, and finally seizures. After identifying a patient with possible opioid toxicity, the clinician should complete the following assessment.Physical Examination a) Assess frequency of myoclonic jerks. Stand at the bedside and observe a patient for 30-60 seconds. Watch for and count the number of uncontrolled jerking movements.
Chart Reviewa) Review recent opioid analgesic history: What is the current drug and dose? How has the dose changed over the past few days and weeks?
Once the assessment process is complete, a rational treatment decision can be made (see Fast Fact #58: Neuroexcitatory Effects of Opioids: Treatment).
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Copyright and Referencing Information: Users are free to download and distribute Fast Facts for educational purposes only. Citation for referencing. Fast Facts and Concepts #57 Wilson RK and Weissman DE. Neuroexcitatory effects of opioids: Patient Assessment. December, 2001. End-of-Life Physician Education Resource Center www.eperc.mcw.edu.
Fast Facts and Concepts was originally developed as an end-of-life teaching tool by Eric Warm, MD, U. Cincinnati, Department of Medicine. See: Warm, E. Improving EOL care--internal medicine curriculum project. J Pall Med 1999; 2: 339-340.
Disclaimer: Fast Facts provide educational information, this information is not medical advice. Health care providers should exercise their own independent clinical judgment. Some Fast Fact information cites the use of a product in dosage, for an indication, or in a manner other than that recommended in the product labeling. Accordingly, the official prescribing information should be consulted before any such product is used.
Creation Date: 12/2001
Purpose: Instructional Aid, Self-Study Guide, Teaching
|Training: Fellows, 1st/2nd Year Medical Students, 3rd/4th Year Medical Students, PGY1 (Interns), PGY2-6, Physicians in Practice|
|Specialty: Anesthesiology, Emergency Medicine, Family Medicine, General Internal Medicine, Geriatrics, Hematology/Oncology, Neurology, OB/GYN, Ophthalmology, Pulmonary/Critical Care, Pediatrics, Psychiatry, Surgery|
ACGME Competencies: Medical Knowledge, Patient Care
Keyword(s): Addiction, Chronic non-malignant pain, Controlled substance regulations, Pain, Pain assessment, Pain treatment
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