Final answer:
The nurse's best action would be to inform the patient of the primary actions of the medication.
Step-by-step explanation:
In this scenario, the nurse's best action would be to inform the patient of the primary actions of the medication. The fact that the medication is categorized as Category X indicates that it is contraindicated for use in pregnancy due to potential harm to the fetus. Therefore, it is important for the nurse to educate the patient about the medication's primary actions and advise her to refrain from getting pregnant while taking it.