Final answer:
For a medication with a low therapeutic index, monitoring serum peak and trough levels is essential to maintain the drug within the safe and effective range and avoid toxicity while optimizing dosage.
Step-by-step explanation:
The most appropriate nursing action for ensuring patient safety with a medication that has a low therapeutic index is monitoring serum peak and trough levels. A low therapeutic index means there is a narrow margin between therapeutic and toxic doses. Therefore, close monitoring of blood levels is critical to ensure the drug stays within the safe and effective range. Therapeutic drug monitoring (TDM) is the practice of measuring specific drug concentrations in the patient's plasma or serum and interpreting these levels to optimize dosing.
Furthermore, due to the significant inter-individual variability and the clear relationship between blood exposure and clinical effects for drugs with a low therapeutic index, serum peak and trough levels provide valuable information for adjusting doses individually. This approach helps both to avoid drug toxicity and to reduce therapeutic costs. Through this monitoring, medical personnel can evaluate dose proportionality, assess the margin of safety, and ensure that therapeutic levels are maintained without reaching toxic levels.