Chapter 26
Clinical Pharmacokinetics and TDM
Using serum drug levels to individualize therapy
What is Therapeutic Drug Monitoring (TDM)?
Therapeutic drug monitoring (TDM) uses serum drug concentrations (SDCs), pharmacokinetics, and pharmacodynamics to individualize and optimize a patient's response to drug therapy.
TDM promotes optimum treatment by keeping the serum drug concentration (SDC) inside a therapeutic range. Above that range, drug-induced toxicity happens too often; below it, the drug is too often ineffective. TDM is not used for every drug -- only for a small group where the level actually guides dosing.
The One-Sentence Definition
TDM = measuring drug levels for a small group of drugs that have (1) a correlation between serum concentration and response AND (2) a narrow range of effective and safe concentrations, to assess patient status as an adjunct to clinical observation.
📖 “TDM: use of SDC for drugs with a correlation between concentration and response and a narrow range of effective/safe concentrations, to assess patient status as an adjunct to clinical observation.”