Abstract
Breakthrough pain is a transient exacerbation of pain that occurs either spontaneously, or in relation to a specific predictable or unpredictable trigger, despite relatively stable and adequately controlled background pain. Typically, breakthrough pain has a fast onset and short duration, and a significant impact on patients' quality of life. Normal-release oral opioids are the traditional pharmacological approach for patients who are receiving an around the clock opioid regimen; however, their onset and duration of action may not be suitable for treating many breakthrough pains. Efforts to provide nonparenteral opioid formulations that could provide more rapid, and more effective, relief of breakthrough pain have led to the development of transmucosal opioid formulations including fentanyl sublingual spray (FSLS). This is a formulation of fentanyl available in doses of 100, 200, 400, 600, and 800 μg strengths approved for the management of breakthrough pain in adult cancer patients already receiving and who are tolerant to opioid therapy for their underlying persistent cancer pain. Published pharmacokinetic, efficacy, tolerability, and safety data suggest that FSLS has a valuable role to play in the symptomatic pharmacological management of breakthrough pain. The effective dose of FSLS is determined by titration according to the needs of the individual patient.