PoPCRN : Research Abstracts : Minimizing Opioid-Induced Sedation

DOZING ON THE ROAD TO OZ: MINIMIZING OPIOID-INDUCED SEDATION, PoPCRN 3/02 Newsletter Clinical Feature

By Daniel Johnson MD, University of Colorado Health Sciences Center, Denver, CO.

One might contend (well, not really) that the 1939 film adaptation of L. Frank Baum's Wizard of Oz is an early pharmacology lecture on the side effects of opioids. Few people can forget the image of the Wicked Witch of the West gazing into her clouded crystal ball, concocting a field of poppies to interrupt Dorothy (played by Judy Garland) and her new-found friends' trek through the land of Oz. Ultimately, Dorothy, Toto, and the Cowardly Lion (the only other "biological creatures") drift into a deep slumber amidst the meadow of poisonous flowers only moments away from their destination - the Emerald City.

There is no question that opioids can provide our patients dramatic relief from multiple symptoms, most prominently pain and dyspnea. Unfortunately, the side effects of opioids can lead some patients and/or providers to limit the use of these drugs despite uncontrolled symptoms.* To some of our patients, their "trek to Oz", a quest to find relief from their pain, is fraught with a trip through the poppy field - daytime drowsiness and mental cloudiness. Depending on the goals of patients and their families, this sedation may create significant distress, especially if it interferes with communication with loved ones.

Some basic points regarding the management of opioid-induced sedation:

• 1. Sedation is most prominent at the initiation (or escalation) of opioid use and typically lessens over several days. Recent studies confirm that morphine produces little measurable impairment of cognitive and psychomotor function, particularly for patients receiving continuous treatment with stable doses. Minimize sedation by using long-acting or sustained release agents (minimizing peaks), combined with an immediate-acting agent for breakthrough symptoms.
• 2. Excessive sleepiness in many patients may represent "catch-up" sleep rather than oversedation. Patients who have just begun opioid treatment often have experienced days to weeks of severe pain and are often deprived of much-needed sleep. Leave the opioid dose the same for the first few days, and if the patient still complains of excessive drowsiness, lower the dose.
• 3. Sedation is often multifactorial. Minimize contributing causes where possible, paying special attention to other medications. Suspect medications include benzodiazepines, barbiturates, cimetidine, anticholinergic drugs (e.g. tricyclic antidepressants), antihistamines, alcohol, and drugs that decrease glomerular filtration in the context of opioid treatment (ACE inhibitors and NSAIDs). Other causes of sedation include infection, brain metastasis, subdural hematoma, hypercalcemia, hyponatremia, uremia or hepatic failure.
• 4. Symptomatic interventions to reduce narcotic induced sedation include changing or reducing the opioid agent or adding a psychostimulant. If sedation persists when contributing factors are eliminated, try decreasing the dose of the sustained-release opioid by 10 to 25% and monitor the patient's use of rescue medication (to assess symptom control). Psychostimulants include methylphenidate (begin at 2.5 mg QD), dextroamphetamine (begin at 2.5 mg QD) and pemoline (for patients who cannot swallow pills, begin at 18.75 mg AM +Noon). In one study, methylphenidate (Ritalin) was effective in reducing drowsiness in over 90% of cancer patients.
• 5. Remember that understanding the patient's (and families) goals of care is critical when assisting patients and families in symptom management decisions at the end of life. For example, for some patients, the drowsiness associated with opioid use may cause little or no distress.

Of interest, a new PoPCRN survey (to be distributed this month), "Hospice Nurses Symptom Management Study" will explore the hospice nurses perceived barriers to effective symptom management. Limiting the use of certain medications secondary to unwanted side effects is one example of a potential barrier to effective symptom management.

References:

• Abrahm JL. A Physician's Guide to Pain and Symptom Management in Cancer Patients. Baltimore: The Johns Hopkins University Press, 2000.
• Dolye, Derek, Hanks, MacDonald, eds. Oxford Textbook of Palliative Medicine, 2nd ed. Oxford: Oxford University Press, 1998.

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