The invention relates to a method of using ulipristal acetate or a metabolite thereof for providing contraception or for treating a patient's condition, comprising providing a patient with ulipristal acetate or a metabolite thereof, and informing the patient or a medical care worker that ulipristal acetate or a metabolite thereof affects activity of a cytochrome p450 isozyme, and that administration of ulipristal acetate or a metabolite thereof with a substance that affects activity of a cytochrome p450 isozyme can affect plasma concentration, safety, efficacy or any combination thereof of ulipristal acetate or a metabolite thereof, the substance, or both.
