A 20 mg Piroxicam or 75 mg Diclofenac sodium intramuscularly show similar results in treating primary dysmenorrhea in the emergency unit, as per a research published in the Medical Science Monitor. NSAIDs are considered as the frequently used agents in treating dysmenorrhea as they help to alleviate menstrual pain by decreasing PGF2alpha levels and uterine pressure in the menstrual fluid. 

A prospective cohort study was conducted to estimate the efficacies of two NSAIDs; Diclofenac sodium and Piroxicam in context to the primary dysmenorrhea with the participants with Visual Analogue Scale (VAS) score greater than five. Selected patients (n = 400) were categorized into two groups (n = 200 each) and either administered Diclofenac sodium or Piroxicam intramuscularly. Pain levels were estimated at baseline and 15, 30, 45, and 60 min. Further, the verbal scale, numeric scale, VAS of 10 cm, pain relapse after 24 hours, additional symptoms and needed analgesics were also noticed.

An average reduction in VAS scores was seen after Diclofenac and Piroxicam introduction. After the 24 hours of treatment, 41 participants of the Diclofenac sodium group and 30 participants of the Piroxicam group required repeat medication with rescue analgesic treatment. Both drugs impact equally on reducing primary dysmenorrhea associated pain.