Therapeutic Drug Monitoring Test

Therapeutic drug monitoring test (TDM) is commonly used to help physicians monitor and maintain drug levels within the therapeutic window. The therapeutic window is the concentration range in which a drug exerts its clinical effect with minimal adverse effects for most patients.
TDM is particularly useful for monitoring drugs that are used long-term or drugs that have a narrow therapeutic range.
Special circumstances may require both peak and trough measures to monitor achievement of short-term therapeutic concentration (peak) and clearance of drug to avoid toxicity (trough).
TDM is also useful to detect and monitor drug interactions and identify inadequate adherence as a cause of poor treatment response. It is important to recognize that the pharmacokinetics of each drug may vary with patient age, sex, weight, clinical status, and the presence of other drugs. TDM parameters are generalized guidelines and are not meant to replace patient assessment and clinical judgment.