The role of pharmacokinetics in (combination) chemotherapy.

Measurements of the behavior of a drug in the body, so-called pharmacokinetics, can help to establish that a given dose of drug reaches its target, that a degree of metabolism, required or not required, takes place, and that clearance either by bile, breath, or urine is achieved. Whereas manipulation of these parameters is not usually of value in improving response rates, insight into pharmacokinetics may often explain failure of effect, may assist in prediction and/or prevention of toxicity, and should be exploited to provide guidelines for optimal dosage and scheduling. In combination chemotherapy, drug monitoring is also indicated to detect and eventually exploit drug interactions.