Nonsteroidal antiinflammatory drug resistance in dysmenorrhea: epidemiology, causes, and treatment.

Although nonsteroidal antiinflammatory drugs can alleviate menstrual pain, about 18% of women with dysmenorrhea are unresponsive, leaving them and their physicians to pursue less well-studied strategies. The goal of this review is to provide a background for treating menstrual pain when first-line options fail. Research on menstrual pain and failure of similar drugs in the antiplatelet category suggested potential mechanisms underlying nonsteroidal antiinflammatory drug resistance. Based on these mechanisms, alternative options may be helpful for refractory cases. This review also identifies key pathways in need of further study to optimize menstrual pain treatment.