Antiretroviral pharmacology and drug–drug interactions

There are now >30 antiretroviral medications available for the treatment of HIV. These drugs have distinct sites of action in the HIV life cycle, and unique pharmacological properties that dictate how they can be used safely in the treatment of HIV. Drug–drug interactions (DDIs) can occur because of alterations to several pharmacodynamic processes, including absorption and drug transport, but hepatic metabolism is clinically the most important. Co-administration of antiretrovirals with other, more commonly used drugs is commonplace, and clinicians must be aware of potential serious interactions that can lead to treatment failure and/or drug toxicity.