Approaches for understanding and predicting drug interactions in human immunodeficiency virus-infected patients.

INTRODUCTION: Knowledge of drug interactions is vital to maximize antiretroviral efficacy and avoid drug-related toxicities. Treatment of co-morbidities has become a difficult task in HIV-infected individuals because pharmacokinetic and/or pharmacodynamic interactions are common when other medications are prescribed along with antiretroviral agents. AREAS COVERED: This article provides an update of the most relevant drug interactions that occur between antiretroviral agents and other drugs. The article additionally revisits how these drug interactions can be prevented from occurring as well as how they can be managed. EXPERT OPINION: Interactions between antiretrovirals and other drugs are frequent in clinical practice. The most common are those affecting drug metabolism due to induction or inhibition of the CYP450, leading to abnormal drug exposure. It is by this mechanism that most HIV protease inhibitors, non-nucleoside reverse transcriptase inhibitors and maraviroc often interact with other medications. In contrast, nucleoside reverse transcriptase inhibitors and some integrase inhibitors, which do not or only marginally affect CYP450, are relatively free of significant pharmacokinetic interactions, although nucleoside analogs might be involved in some pharmacodynamic interactions.