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Previous Tips:Methadone: Starting Dosing Information
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Opioids and Nausea (article one of two) Author: David E. Weissman MD Background: Why do patients get nauseated and vomit after receiving an opioid? Commonly described as an “allergy”, opioid-induced nausea/vomiting is not an allergic reaction. In fact, rather than indicating a pathologic reaction, nausea indicates normal functioning of the brain. Opioid-induced nausea occurs through the following mechanisms:
Do all opioids produce the same degree of nausea? There is little research on this topic. In clinical practice, morphine and codeine are often mentioned as the worst offenders. Why are some patients more sensitive to the emetic effects of opioids than others? Unknown. What is the natural history of opioid-induced nausea? Most patients develop tolerance to the emetic effects, so that within 7-10 days, at a constant opioid dose, What are management approaches?
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Controlled Release Oxycodone Author: David E. Weissman, MD Background: Controlled release oxycodone (CRO) has received considerable attention in the lay press over the past several years. Much of the coverage has been negative, related to the illicit use of CRO due to diversion outside of legitimate medical practice, CRO is an effective long acting oral opioid product, very similar to control released morphine. This article reviews CRO usage in palliative care. Indication: CRO is indicated for moderate to severe pain requiring continuous, around the clock analgesia for an extended period of time. Pharmacology: Oxycodone is a semi-synthetic opioid that interacts with both mu-and kappa-opioid receptors, but behaves in most respects identically to morphine. CRO has greater oral bioavailability than morphine, and a bi-phasic absorption pattern, with peaks at 37 minutes and 6.2 hours. Peak pain relief occurs in one hour. Unlike morphine, oxycodone has minimally active metabolites, demonstrating little to no analgesic or anti-analgesic properties. Oxycodone should be used with caution in patients with renal and liver impairment and avoided in in hemodialysis patients. CRO can lead to all the traditional opioid side effects. Anecdotal reports suggest less nausea and hallucinosis compared to morphine, although these observations have not been substantiated in controlled trials. Equianalgesic Information: Studies comparing round the clock immediate release oxycodone to controlled release oxycodone products demonstrate equivalent results. The conversion factor between between morphine and oxycodone has been controversial, but the most commonly accepted data suggests that 30 mg of morphine is equivalent to 20 mg of oxycodone. Since all equianalgesic values are rough guidelines, prescribers need to use their clinical judgment in determining the most appropriate starting dose. Dosage: The starting dose of CRO in an opioid naïve patient is 10 mg q 12 hours; Cost: CRO is more expensive than generic long-lasting morphine; there is currently no generic CRO on the market. Diversion: CRO has been associated with greater diversion to the illicit drug market than morphine. Illicit users will commonly crush the tablet then chew, snort, or dissolve the product in water for intravenous injection. CRO can bring $1.00 per milligram or more on the illicit market. Summary: CRO oxycodone is an effective long-acting oral opioid. Due to cost and concerns about diversion, controlled release morphine is the drug of first choice for a long- acting oral opioid product. There is not data that CRO offers any analgesic References: Regional Hospice We’re here when you need us. Medical Director: Dr. Jeff Lewis Nursing Director: Lynda Anderson Executive Director: Joe Muench Ashland Office: Hayward Office:
Previous Tips:Methadone: Starting Dosing Information
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