Final answer:
The client demonstrates a good understanding of amitriptyline therapy by acknowledging that they should notify their doctor if they experience blurred vision, a potential side effect of the medication.
Step-by-step explanation:
When assessing the understanding of a client diagnosed with major depression and starting on the antidepressant amitriptyline hydrochloride, the nurse can determine that the client has a good understanding of the drug therapy if the client acknowledges potential side effects and the importance of continuing medication even after feeling better. In the given options, the correct statement that reflects a good understanding is: "I'll notify my doctor if I experience blurred vision." This statement is correct because blurred vision is a potential side effect of amitriptyline, and the client should report it to the doctor. Furthermore, patients should not discontinue amitriptyline abruptly based on feeling better, as antidepressants need to be taken consistently for several weeks to have a beneficial effect, and stopping them suddenly can lead to withdrawal symptoms or relapse.
Option d regarding the drug causing dry mouth is also an accurate understanding of a common side effect of amitriptyline. However, option c specifically refers to an action tied to adverse effects, which indicates better understanding of critical responses to therapy.