One Step Closer to the Target: Intracellular Pharmacokinetics of Gemcitabine

Drug dosing is based on the premise that the amount of drug given influences the toxicity and response. The premise of pharmacokinetics is that it is not the amount of drug given, but the amount the patient is exposed to, that determines drug effect. Measurements of drug exposure are usually performed by determining the concentration in serum or plasma. This accounts for variability in drug clearance in determining the patient’s exposure. This has resulted in such dosing strategies as carboplatin dosing based on creatinine clearance, therapeutic dose monitoring of methotrexate and pharmacogenetically modified dosing for irinotecan.