All of the following drugs are used in treating spasmodic dysmenorrhoea, EXCEPT:

NSAIDS, steroid contraceptives, gonadotropin releasing hormone agonists and androgens are the commonly used drugs for the treatment of dysmenorrhea. Commonly used NSAIDS are ibuprofen, naproxen, mefenamic acid and ketoprofen. Combination hormone bih control methods and progestin-only contraceptives are also used to treat dysmenorrhea. Both NSAIDs and steroid contraceptives acts by reducing prostaglandin production. Gonadotropin-releasing hormone agonists and androgens such as danazol by its estrogen lowering effects leads to endometrial atrophy and lower prostaglandin production. Ref: Hoffman B.L., Schorge J.O., Schaffer J.I., Halvorson L.M., Bradshaw K.D., Cunningham F.G., Calver L.E. (2012). Chapter 11. Pelvic Pain. In B.L. Hoffman, J.O. Schorge, J.I. Schaffer, L.M. Halvorson, K.D. Bradshaw, F.G. Cunningham, L.E. Calver (Eds), Williams Gynecology, 2e.