Feminax ultra contains 250mg of naproxen which is used to treat menstrual pain or dysmenorrhoea or more commonly known as period pains feminax ultra tablets provides long lasting relief for up to 8 hours and works directly at the site of the pain relieving period pains and cramps feminax can be purchased without a prescription and is suitable for women between the ages of 15 50 years old it is better to start taking feminax ultra the very first day of your period periods are caused by t