The Nurse Is Speaking with a Female Client Taking Phenytoin

The nurse is speaking with a female client taking phenytoin (Dilantin) for seizure control. The client states that she has started using birth control pills to prevent pregnancy. Which of the following would be an important point for the nurse to stress to the client?

A) Oral contraceptives decrease the effectiveness of phenytoin.
B) Severe gastrointestinal side effects can occur when phenytoin and oral contraceptives are taken together.
C) There is an increased risk of thrombophlebitis when phenytoin and oral contraceptives are taken at the same time.
D) Phenytoin may decrease effectiveness of birth control pills, and additional measures should be taken to avoid pregnancy.