Final answer:
A full therapeutic response to levodopa may take several months. Levodopa should be taken on an empty stomach, as high-protein foods can decrease its absorption. A common side effect of levodopa is vivid dreams.
Step-by-step explanation:
The nurse should inform the family member that a full therapeutic response to levodopa may take several months (A). It is important to manage expectations and understand that it may take time for the medication to have an optimal effect. The nurse should also emphasize that levodopa should be taken on an empty stomach, as high-protein foods can decrease the absorption of the medication (B). Lastly, the nurse should mention that a common side effect of levodopa is vivid dreams (C), which is important for the family member to be aware of.