Final answer:
The most appropriate nursing action is to perform discharge teaching regarding the drug.
Step-by-step explanation:
The most appropriate nursing action when a client with angina is experiencing migraine headaches and has been prescribed Sumatriptan succinate (Imitrex) is to perform discharge teaching regarding the drug. It is important for the nurse to educate the client about the drug, including its purpose, dosing instructions, potential side effects, and any precautions or contraindications. By providing comprehensive education, the nurse can ensure that the client understands how to take the medication safely and effectively.