Approved for medical use in 2010, Ulipristal acetate is a medication used for emergency birth control and uterine fibroids. As emergency birth control, this drug should be used within 120 hours of unprotected intercourse. This medication basically works by preventing the effects of progesterone, thus stopping ovulation. Bear in mind that Ulipristal acetate has certain side effects that need to be taken into consideration such as headache, nausea, feeling tired, and abdominal pain. Remember that this drug should not be used in people who are already pregnant. You should take Ulipristal acetate exactly as your doctor tells you to. You will be asked to start taking the tablets during a week you are having a period. You can take your tablets before or after food. And if you forget to take a dose, take it as soon as you remember unless you are more than 12 hours late.