Pain relief injections usually work in about 20 minutes. When a patient has incisional pain or drainage port pain after surgery, pain relief injections are needed for analgesia. At first, choose a non-steroidal anti-inflammatory drug, because the analgesic effect is relatively weak on it, and choose parecoxib for the injection. If the patient’s pain is still very obvious, you can choose a drug with a slightly stronger analgesic effect, such as tramadol. If the patient’s pain is still very severe and cannot be relieved, or if the patient has advanced tumor with cancer pain, it is generally recommended to choose opioid analgesics, such as morphine or pethidine, which are more effective. It is usually given temporarily, and if long-term administration is needed, it needs to be given twice/day with an interval of 12 hours.