[Management of opioid-induced nausea and vomiting]

Opioids are available for patients with chronic non-cancer pain. At the start of treatment, side effects such as nausea and vomiting may occur. As these symptoms appear at a dose lower than that at which analgesic actions are achieved, preventive strategies are important. CTZ stimulation, vestibular stimulation, and motor stagnation of the digestive tract may be involved in the mechanism of opioid-induced nausea and vomiting (OINV). To prevent these symptoms, it is recommended that each mechanism-matched antiemetic agent be administered. Anti-dopaminergic, antihistaminergic, and digestive tract movement-enhancing agents are used as first-choice drugs, respectively. However, it must be considered that the long-term administration of antiemetic agents may cause extrapyramidal symptoms. It is also effective to use opioid rotation or change the administration route from oral to continuous subcutaneous administration. However, concerning chronic, non-cancer pain, the opioid rotation regimen is limited to a combination of codeine preparations, morphine preparations, and fentanyl patches. For long-term administration, the continuous intravenous/subcutaneous injection of opioids is not indicated.