Why don't NSAIDS always help with period pain?

There are many reasons why NSAIDS might not work. However, new work by our lab provides evidence that absorption may be partially responsible for ineffectiveness:

To explain the etiology of NSAID resistance, we evaluated naproxen absorption and metabolism in relation to pain relief in a pilot study of women with dysmenorrhea. Our preliminary findings suggest that poor drug absorption contributes to ineffective pain relief in dysmenorrheic women. Future studies should explore whether malabsorption contributes to NSAID resistance for other pain conditions. To read the full publication see below:

https://academic.oup.com/painmedicine/advance-article/doi/10.1093/pm/pnaa133/5850634?guestAccessKey=a307b51f-366c-40bf-a296-1b75ee1fcc28