Hao, J., Wang, K., Shao, Y., Cheng, X., & Yan, Z. (2013). Intravenous flurbiprofen axetil to relieve cancer-related multiple breakthrough pain: A clinical study. Journal of Palliative Medicine, 16, 190–192.

To compare the effects of immediate-release morphine to those of flurbiprofen axetil in the treatment of cancer-related breakthrough pain

For the treatment of cancer-related breakthrough pain, patients in the flurbiprofen group received 50–100 mg flurbiprofen axetil IV and patients in the control group received a proportional dose of immediate-release morphine. Incidents of breakthrough pain were assessed for three days.

• The sample was composed of 217 patients.
• Mean patient age was 49.7 years.
• Of all patients, 60% were male and 40% were female.
• Cancer types in the sample included lung, prostate, breast, liver, esophagus, and pancreas cancers. All patients had severe pain that they rated at 7 or higher on a visual analog scale. Patients' background pain was controlled, and all patients experienced multiple instances of breakthrough pain.

• Single site
• Inpatient
• China

Two-group observational study

• Visual analog scale (VAS)
• Number of breakthrough episodes
• Time to relief of breakthrough pain
• World Health Organization criteria for adverse events

Average time to meaningful pain relief following administration of the rescue medication was 16 minutes in the flurbiprofen group and 27.3 minutes in the morphine group (p < 0.01). Patients in the flurbiprofen group and the morphine group received significant reduction in pain, from an average of 7 to 2.2 or 3.0, respectively, on the VAS. The number of breakthrough episodes was significantly lower in the fluribprofen group than in the morphine group (p = 0.000). Most patients needed 50 mg flurbiprofen; only five patients required a dose increase. No serious complications were observed. The prevalence of side effects was similar in both groups

IV flurbiprofen may be an effective intervention for cancer-related breakthrough pain.

• The study had risks of bias due to no blinding and no randomization and as a result of sample characteristics.
• Authors did not specify unintended interventions or other interventions that would influence results. 
• Measurement tools and methods were not well described.
• The study does not state clearly if patients were assigned to study groups or if assignment was random. The timing of pain assessments is unclear. Authors provide no information about background analgesics or duration of pain.
• Authors defined adequate pain control at baseline as pain with a VAS rating of 7 or higher. Whether this is actually adequate control is questionable. In addition, the study does not specify whether the VAS rating referred to worst pain or usual pain.

Flurbiprofen appears to be a promising agent for the management of cancer-related breakthrough pain. This study has several limitations. Further research regarding flurbiprofen is warranted.