Breakthrough pain and rapid-onset opioids in patients with cancer pain: a narrative review.

Breakthrough pain is transitory pain that occurs despite the use of opioids for background pain control. Breakthrough pain occurs in 40% to 80% of patients with cancer pain. Despite effective analgesic therapy, patients and their caregivers often feel that their pain is not sufficiently controlled. Therefore, an improved understanding of breakthrough pain and its management is essential for all physicians caring for patients with cancer. This article reviews the definition, clinical manifestations, accurate diagnostic strategies, and optimal treatment options for breakthrough pain in patients with cancer. This review focuses on the efficacy and safety of rapid-onset opioids, which are the primary rescue drugs for breakthrough pain.