A nurse is reinforcing teaching with a client who has a new prescription for amitriptyline. The client reports taking herbal supplements. The nurse should instruct the client that they should avoid taking which of the following supplements?

A. Echinacea is primarily used to support immune function and does not have a significant interaction with tricyclic antidepressants like amitriptyline. B. St. John's wort can increase serotonin levels and may interact with antidepressants, increasing the risk for serotonin toxicity. It should be avoided when taking amitriptyline. C. Saw palmetto is typically used for benign prostatic hyperplasia and does not significantly interact with amitriptyline. D. Glucosamine is commonly used for joint health and does not have a known serious interaction with amitriptyline.