Drug-drug interactions with newer antiretroviral agents.

Knowledge of drug interactions among antiretroviral agents and other drugs used by HIV-infected patients is essential to maintaining safety and efficacy of drug treatment. Often, the clinical impact of drug-drug interactions cannot be predicted on the basis of pharmacokinetic interactions alone, highlighting the need for studies and analyses that provide exposure-response data. Drug interactions in HIV-infected patients can be complex and sometimes counterintuitive, and practitioners must increasingly rely on a concerted approach to gathering information on drug interactions that goes beyond studies showing exposure changes for coadministered drugs.