[For the Clinical Use-Clinical Guidelines for Pharmacological Management of Cancer Pain 2020].

The Japanese Society of Palliative Medicine published its first clinical guidelines for pharmacological management of cancer pain in 2010. The guidelines were thereafter revised in 2014 and 2020. In this article, the 2020 revised edition is discussed. Regarding the compilation principles, the 2020 edition differs from the previous editions in that evidence rating was made concerning randomized comparative trials alone with only a few exceptions. Recommendations were made about 28 clinical questions, but they are classified according to the contents into those regarding(1)analgesics,( 2)adverse effects of opioids, and(3)treatments under special circumstances. A major point of change concerning recommendations is that potent opioids were recommended(strong recommendation)for patients with moderate or severe pain and that weak opioids( eg, tramadol, codeine)were recommended(weak recommendation)only when potent opioids cannot be used. In addition, recommendations were made concerning the following new clinical questions. 1. The administration of methadone is recommended(strong recommendation)for patients with cancer pain in whom appropriate analgesia cannot be obtained even with potent opioids. 2. Fentanyl injection or buprenorphine injection is recommended as the first-line opioid for patients with severe kidney dysfunction, and the use of morphine and codeine should be avoided(strong recommendation). 3. Continuous administration of opioid injection should be performed for more rapid analgesia in patients with severe pain (strong recommendation).