Final answer:
The nurse should prioritize teaching the client how to titrate the medication based on pain.
Step-by-step explanation:
The nurse should prioritize teaching the client about how to titrate the medication based on pain. Titrating the medication allows the client to adjust the dose to achieve optimal pain relief without experiencing excessive side effects or sedation. By teaching the client how to titrate the medication, the nurse empowers the client to actively manage their pain and take control of their pain management plan.