Hi, Primolut-N contains norethisterone which is a synthetic analogue of Progesterone which helps control the uterine bleeding. This drug is commonly prescribed for dysfunctional uterine bleeding, menorrhagia, polymenorrhea, premenstrual symptoms, etc. It regulates the uterine bleeding by controlling the uterine endometrial growth and shedding during the menstrual cycle. Common side effects of the drug are abnormal vaginal spotting, breast tenderness, dizziness, headache, nausea, vomiting, diarrhoea, etc. Tablet should be taken as per advice of your doctor. There may be withdrawal bleeding after stopping the medication. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Pradeepraj, General & Family Physician