Therapeutic Drug Monitoring of Therapy for Infectious Diseases

Abstract

Optimal use of antimicrobial agents is dependent on a multitude of factors. Empiric therapy should be based on the patient's underlying disease states, the most likely organisms suspected, and susceptibility patterns. Once susceptibilities are known, therapy should be streamlined. A number of factors must be evaluated during therapy. The site of infections must be considered when choosing antimicrobial agents. The minimum inhibitory concentration (MIC) should be evaluated ; the antimicrobial agent's MIC should be at or below the breakpoint for the organism to be considered susceptible. Antimicrobial agent selection and dosing should take into consideration not only the MIC, but also the post-antibiotic effect, if applicable. Serum concentrations of antimicrobial agents should be obtained and evaluated to ensure therapeutic levels and to avoid potential toxicities. The choice of an antimicrobial agent is complicated by the emergence of antibiotic resistance. Drug-resistant gram-positive and gram-negative infections are increasing. We must attempt to control resistance by choosing appropriate antimicrobial agents and maximizing dosages. Pharmacists can play a critical role in the management of patients who receive antimicrobial agents.