Opioid analgesics mainly include fentanyl and pethidine. Opioid analgesics are alkaloids extracted from the opium poppy and derivatives in vitro and in vivo that provide pain relief by interacting with center-specific receptors. Common opioid analgesics include dihydrocodeine, methadone, fentanyl, and pethidine, which are mainly used for the treatment of moderate to severe pain, such as that caused by cancer. Opioid analgesics have a certain degree of dependence, cancer patients usually need to use opioid analgesic treatment for a long period of time, which can cause the body to tolerate addiction, symptoms such as anxiety, muscle pain, insomnia, and other symptoms, but also nausea, vomiting, constipation, respiratory depression and other adverse reactions. During treatment with opioid analgesics, doctors usually take active precautions to minimize or avoid adverse drug reactions. If there is a need for medication, it should be used as prescribed by a doctor and not blindly self-administered.