Pain shots usually work in about 20 minutes. When the patient after the operation, if the incision pain or the drainage tube mouth pain, need to be analgesic injection for analgesia. At first, choose non-steroidal anti-inflammatory drugs, because the analgesic effect is relatively weak can be, choose parecoxib to carry out the injection. If the patient’s pain is still very obvious, you can choose a slightly stronger analgesic effect of the drug, such as tramadol. If the patient’s pain is still very serious and not able to stop the pain, or patients with advanced tumors, cancer pain, it is generally recommended to choose opioid analgesics, such as morphine or pethidine, the effect is better. It is usually given temporarily, and if long-term administration is needed, it needs to be given 2 times/day at 12-hour intervals.