ABSTRACT
The most common include constipation, nausea, and sedation, while dose-limiting side effects typically involve the central nervous system and include cognitive impairment, delirium, and myoclonus. In the noncancer setting, approximately 40% of chronic opioid users for pain management develop constipation. The exact prevalence of opioid-induced nausea is not known but estimated to be approximately 25%. A number of different antiemetic medications can be used to effectively to treat opioid-induced nausea and vomiting in palliative care patients, such as dopamine antagonists metoclopramide and haloperidol. For the management of opioid-induced nausea, a recent systematic review concluded that there is limited evidence to prioritize between symptomatic treatment and opioid adjustments in cancer patients. Opioid-induced neurotoxicity refers to a constellation of neuropsychiatric symptoms such as excessive sedation, cognitive impairment, delirium, hallucinations, myoclonus, seizures, and hyperalgesia.
