Designing drug regimens for special intensive care unit populations

Table 5 Pharmacokinetic considerations in the critically ill patient

Data from pharmacokinetic studies are no substitute for clinical monitoring of the individual patient’s response to therapy

Pharmacokinetic parameters derived from studies involving normal volunteers or less severely ill patients are not directly applicable to the critically ill patient

Average parameters for volume of distribution and clearance are larger and have much greater variability in critically ill patients compared with less severely ill patients

The duration of action of single or isolated IV doses of more lipophilic drugs used in the ICU is a function more of distribution than of clearance

The values for volume of distribution and clearance frequently change from baseline with prolonged drug administration because of factors such as accumulation or altered elimination

For drugs with active metabolites, the pharmacokinetics of the metabolites as well as the parent compound must be considered

Drug absorption is important not only with oral or enteral administration but also with intramuscular and subcutaneous injections

Reprinted with permission from Erstad[56]. ICU: Intensive care units.