For cancer pain, a three-stage approach to analgesia is currently used. The analgesic drugs used in each stage vary if optimal pain relief is achieved. In the first stage, start with non-opioid analgesics, such as aspirin and anti-inflammatory pain suppositories. If relief is not achieved at this point, add weak opioid analgesics on top of this. In the second stage, paracetamol, aspirin or a non-steroidal anti-inflammatory drug can be used in combination with an immediate-release weak opioid analgesic, such as codeine, dihydrocodeine, tramadol, etc., or a combination of a low-dose opioid, such as morphine, oxycodone, etc. In the third stage, for patients with severe cancer pain, morphine is most commonly used and preferred for oral administration, mainly including morphine sulfate extended-release tablets, oxycodone hydrochloride extended-release tablets, fentanyl transdermal patches, buprenorphine transdermal patches, etc.