Pharmacometrics: Alternative approach of quantitative pharmacology

The needs of understanding the pharmacokinetics and pharmacodynamics by researchers and physicians to give the best rational therapy for the patient is high. Pharmacokinetics and pharmacodynamics characteristics are usually obtained from phase one and phase two of clinical trials which are mainly involved healthy subjects and patients with restricted criteria, respectively. In special populations, such as pediatric, pregnant women, patient in critically ill condition or organ dysfunction, show different physiology condition which could alter pharmacokinetics and pharmacodynamics of the drug. Therefore, data from phase one and two of clinical trials might not represent the daily clinical practice conditions, where physicians have to prescribe drug to the patient in various conditions. On the other hand, special populations is not able to be included as subjects in clinical trials because of the ethical reasons. Therefore, pharmacometrics is an alternative method that can be used to provide pharmacokinetics and pharmacodynamics data on special populations, which more reflect daily clinical practice conditions. This method applies mathematical and statistical concept to explain the relationship between dose, plasma drug concentration, drug response and covariate factors in particular conditions. Moreover, it can be used widely in drug development processes, from in vitro to clinical trials.