Digoxin and furosemide were prescribed for a client with chronic heart failure, and the home health nurse is evaluating the client's self-care knowledge of these drugs. Which statement indicates that the client has a good understanding about the use of these drugs?

A. Low-density lipoprotein (LDL): Atorvastatin's primary effect is to decrease LDL cholesterol levels. A decrease in LDL levels would indicate the medication is working as intended, not an increase.
B. Prothrombin time (PT): PT is a measure of blood clotting, which is not directly affected by atorvastatin. This value is more relevant for monitoring anticoagulant therapy.

C. Creatine phosphokinase (CK): CK levels can be used to monitor for muscle damage or side effects related to statin use. An increase in CK levels would suggest muscle damage, not the effectiveness of the statin.
D. High-density lipoprotein (HDL): Atorvastatin is a statin medication used to lower cholesterol levels, particularly low-density lipoprotein (LDL) cholesterol, which is a key target in reducing the risk of coronary artery disease (CAD). While the primary goal of atorvastatin is to lower LDL cholesterol, an increase in HDL cholesterol (often termed "good" cholesterol) is also desirable as it can help reduce the risk of CAD. Therefore, an increase in HDL is a positive indicator that the medication is having a beneficial effect.

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.