The Role of Therapeutic Drug Monitoring in the Management of HIV-infected Patients.

The concept of targeting drug therapy based on plasma concentrations, also called therapeutic drug monitoring (TDM), has been used in the treatment of infectious diseases and other illnesses for decades. A number of clinical trials have demonstrated that drug concentrations are an important factor in response to therapy for HIV, but whether TDM will become a tool for the routine management of HIV infection remains to be determined. The concept of the inhibitory quotient, which integrates drug concentrations and resistance testing, also shows promise in a number of retrospective analyses. Logistical problems still remain with regard to its feasibility, and theoretical issues such as protein binding, variability, and the appropriate time of sampling continue to be debated. A growing body of literature supports the concept of TDM in HIV, but it is important that it be used with other interventions such as resistance testing, adherence monitoring, and patient counseling to be an effective tool in patient management.