What is the purpose of therapeutic drug monitoring?

• A. To optimize efficacy and minimize toxicity by measuring drug levels and adjusting dosing
• B. To screen for allergies
• C. To determine patient satisfaction
• D. To assess liver function

Answer: (A)

Therapeutic drug monitoring is about keeping drug exposure within an optimal range by measuring blood levels and adjusting the dose accordingly. For meds with a narrow therapeutic window or highly variable pharmacokinetics, checking concentrations helps ensure the medicine is effective while avoiding toxicity. The process involves timing the sample (often just before the next dose for a trough level, or at a specific time for certain drugs), comparing the result to established targets, and tweaking the dose or dosing interval based on the patient’s factors—kidney and liver function, drug interactions, age, weight, and adherence. This approach directly aims to maximize efficacy and minimize adverse effects.

Screening for allergies, assessing patient satisfaction, or evaluating liver function are not the goals of therapeutic drug monitoring; they address different clinical questions.