Therapeutic Monitoring, the Concentration-Effect Relationship and Impact on the Clinical Efficacy of Antibiotic Agents

Summary

Therapeutic monitoring is now technically feasible for a wide variety of antibiotic agents and data are accumulating on the relationship of blood levels and clinical efficacy. For each antibiotic a therapeutic range and dosage regimen can be based theoretically on its known pharmacokinetics, pharmacodynamics in vitro, and also use in animal and human treatment studies. Antibiotics can be characterised into two types by their mechanism of kill, as either concentration-dependent (for which achieving a large post-dose concentration to MIC ratio appears important) or concentration-independent / time-dependent (where efficacy is related to maintaining the overall concentration above the MIC).

Hopefully, concentration-controlled trials will be performed when new antibiotics are introduced, to determine a therapeutic range which correlates with clinical efficacy, and so enable monitoring to lead to a more rational approach to antibiotic administration.

Key words::

• Concentration-effect relationship
• clinical efficacy
• therapeutic monitoring