Assessing Hydromorphone Sustained-Release Tablets in Elderly Cancer Pain Patients With Renal Insufficiency

This clinical study aims to understand whether domestic hydromorphinone sustained-release tablets are effective and safe in treating moderate to severe cancer pain in elderly patients with renal insufficiency. It will also understand key safety concerns, especially regarding renal function and neurotoxicity. The main questions it aims to answer include:1. Can hydromorphinone sustained-release tablets effectively relieve the pain of such patients and improve their quality of life?2. During the treatment period, what effect does this drug have on renal function (measured by eGFR)? 3. In this specific population, what are the occurrence and characteristics of neurotoxicity and other side effects induced by opioids? Researchers will compare elderly cancer pain patients with renal insufficiency with those with normal renal function (both receiving the study drug treatment) to observe whether there are differences in efficacy and safety results. Participants will: Receive a standardized treatment plan: First, subcutaneous injection of hydromorphinone injection for dose titration, and then switch to daily oral administration of hydromorphinone sustained-release tablets for 4 weeks. Visit the clinic for assessment and examination (including renal function tests) during the baseline period, on the 7th day, and at the weekends of the 2nd, 3rd, and 4th days. Regularly monitor and record the degree of pain, the occurrence of explosive pain, the use of medication, and any side effects.