The Client Has Been Started on Elavil

The client has been started on Elavil. He tells the nurse that he does not take any other medication except for St. John's wort, which he has found to be mildly therapeutic. What should be the nurse's highest priority response to this information?

A) The combination of Elavil and St. John's wort can be particularly therapeutic.
B) Use of St. John's wort can cause the dosage of Elavil to require increase.
C) Use of St. John's wort can cause the Elavil to be completely ineffective.
D) The combination of St. John's wort and Elavil can produce serotonin syndrome.