Fentanyl transdermal patch costs about 70-80 yuan for one patch. Fentanyl transdermal patch is mainly composed of fentanyl, which is an opioid analgesic with strong analgesic effect, mainly used for cancer pain or chronic pain treatment, mostly for patients who are not able to take oral pain medication via mouth. The transdermal patch can be applied to the abdominal wall, and it is important to ensure that the transdermal patch is completely applied to the abdominal wall when it is applied, so that effective absorption can be achieved, and the effect of the drug will deteriorate after about three days. However, when replacing the transdermal patch after three days, the original transdermal patch should not be discarded at will, as it still contains a lot of fentanyl drug components inside.