Disclosures of Competing Interests: This letter to the editor was completed without any external funding. 18 No commercial organizations had any role in the writing of this paper for publication. 20 request from the corresponding author) and declares: no financial relationships with any organizations that 21 might have an interest in the submitted work in the previous 3 years.

Therapeutic drug monitoring (TDM) is the clinical practice of measuring specific drugs at designated intervals to maintain a constant concentration in a patient's bloodstream, thereby optimizing individual dosage regimens. It is unnecessary to employ TDM for the majority of medications, and it is used mainly for monitoring drugs with narrow therapeutic ranges, drugs with marked pharmacokinetic ...