Breakthrough pain (BTP) is episodic pain that emerges through the treatment of otherwise well-managed chronic background pain. Often called pain flare or transient pain, BTP negatively affects the function and quality of life of the patient and often results in a number of other physical, psychological and social problems. Breakthrough pain is a common occurrence affecting approximately two-thirds of the estimated 50 to 100 million chronic pain sufferers in the US. It can have multiple causes wi