The nurse is assessing a client who was recently diagnosed with Parkinson's disease (PD) and is taking carbidopa-levodopa. The client is concerned that the medication is not working. Which intervention should the nurse implement first?

A) Determine if the client is taking the medication before meals: While the timing of medication relative to meals can affect absorption, this action assumes a specific problem without first clarifying the client's concerns. It's important to understand the nature of the client's issue before assessing medication administration. B) Ask if his morning voiding is dark colored: Dark-colored urine may be a side effect of some medications, but this is a less direct approach to understanding why the client feels the medication is not working. It does not directly address the effectiveness of the medication. C) Explore what the client means by the drug not working: This is the most appropriate initial intervention. Understanding the client's perception and specific concerns about the medication's effectiveness will guide further actions, such as assessing medication adherence, side effects, or the need for a medication adjustment. D) Evaluate the client for signs of dyskinesia: While assessing for dyskinesia is important, it is more of a specific follow-up step. The priority is to understand the client's concerns about the medication's overall effectiveness before focusing on specific side effects.