Fulminant pain is the most common form of intractable pain. Most cancer pains are persistent and chronic. Maintaining appropriate blood levels of pain medication on time will effectively relieve chronic pain in most cancer pain patients. However, many patients with cancer pain may still have frequent episodes of explosive pain along with persistent chronic pain. The main reasons for frequent episodes of explosive pain: 1. characteristics of certain pain lesions themselves, for example, about 63% of patients with bone metastases are accompanied by activity-related explosive pain. 2. Inadequate doses of long-acting pain medications or progression of the disease, requiring adjustment of the pain medication dose. 3. The efficacy of pain medication is not maintained for as long as the medication is given on time, which is a weakness of long-acting opioids themselves, known as the end-dose release problem of long-acting pain medication. For example, sometimes the effect of fentanyl transdermal patch is less than 72 hours, and the effect of morphine controlled-release tablets is less than 12 hours. Warm tip: For predictable bursts of pain, choose opioid immediate-release agents for early prophylactic dosing, such as 30 minutes before an event. For unanticipated pain flare-ups, choose lipid-soluble opioid immediate-release agents. Fentanyl “lollipop” through the mucous membrane of the oral inhalation is the ideal relief of explosive pain, when the drug can be contained under the tongue, the drug quickly and effectively through the sublingual mucosa into the systemic blood circulation, pain relief effect of 5 to 10 minutes, similar to the onset of action of morphine intravenous drugs.