Treatment Guidelines for the Use of Antiretroviral Agents in HIV-Infected Adults and Adolescents: An Update

Drug Interactions

Given the availability of numerous once-daily ART regimens, prescribing ART has been greatly simplified. Nonetheless, there are many pharmacokinetic drug-drug interactions between antiretroviral drugs and concomitant medications. When changing either the ART or adding or changing other medications, the clinician must always pay attention to potential drug-drug interactions. Consideration must be given to the interaction with drugs that affect antiretroviral absorption—particularly, acid-reducing agents and products that contain polyvalent cations, including calcium and magnesium.

When antiretrovirals that undergo hepatic metabolism are given with other drugs that also are metabolized by the cytochrome P450 enzyme system or other hepatic enzymes, the levels of antiretrovirals or other drug may be significantly increased or decreased. ¹ The 2 booster—cobicistat and ritonavir—used to increase certain antiretrovirals levels also may alter the metabolism of other drugs. ^28,29 The new guidelines contain updated and detailed tables on drug-drug interactions. Given the comorbid conditions, particularly among those aging with HIV, polypharmacy is an increasingly common concern. It is essential for clinicians to work with knowledgeable HIV pharmacists to ensure the correct and safe prescribing of all medications.

HIV/AIDS Demographics in U.S.

Of the more than 1.2 million people aged > 13 years in the U.S. living with HIV, about 1 in 8 are unaware of their infection. ³⁰ The Centers for Disease Control and Prevention (CDC) estimates that about 50,000 people are newly infected every year. ³¹ Men who have sex with men (MSM) are the group most impacted by HIV, and African American MSM are disproportionately represented. Although MSM were only about 4% of the U.S. male population in 2010, 78% of the newly diagnosed HIV infections among males were in MSM (63% of all new HIV infections). ^32,33 The groups at greatest risk of HIV infection are now young black and Latino MSM aged 13 to 24 years. ³³ Decreasing the rate of new HIV infections in this high-risk population remains challenging.

Across the U.S., the HIV epidemic continues to disproportionately impact southern states. An estimated 44% of all people living with HIV in the U.S. reside in the District of Columbia and in 16 southern states. ³⁴ Among the 10 states with the highest death rate for persons diagnosed with HIV, 7 are southern states–Louisiana, Alabama, Mississippi, South Carolina, Kentucky, and Maryland. ^35,36 The HIV epidemic in southern states is not confined to urban centers but instead extends across rural areas that have limited access to adequate health care and high rates of poverty. ³⁷

HIV Care Continuum

In July 2013, President Obama established the HIV Continuum Care Initiative directing federal departments to accelerate efforts and direct resources to increase the proportion of HIV-infected persons successfully receiving care in each stage of the continuum as part of the National HIV/AIDS Strategy. ^38,39 In November 2014, the CDC released a report on HIV in the U.S. that found about 14% of those with HIV infection have never been diagnosed, and only 40% are receiving HIV medical care. ⁴⁰ Despite the much improved and simplified ART regimens, only 30% of those living with HIV infection in the U.S. have achieved viral suppression. The CDC has outlined 4 steps for achieving viral suppression, the ultimate goal of all HIV treatment (Table 2). ⁴¹