Final answer:
The nurse should instruct the client to report chest pain to the provider as an adverse effect of sumatriptan.
Step-by-step explanation:
The nurse should instruct the client to report chest pain to the provider as an adverse effect of sumatriptan. Chest pain can be a serious side effect that should be evaluated by the healthcare provider. Increased appetite, drowsiness, and dry mouth are common side effects of sumatriptan and may not require immediate reporting but should be mentioned to the healthcare provider at the next follow-up appointment.