amfAR, The Foundation for AIDS Research

The Clinical and Economic Benefits of Once-Daily Pills

Antiretroviral therapy (ART) has come a long way in making HIV a manageable chronic infection. In the 30 years of the epidemic, more than 20 antiretroviral agents have been approved by the U.S. Food and Drug Administration. The broader availability of newer, safer drugs and studies reporting on side effects of older drugs led the World Health Organization (WHO) to change its treatment guidelines in 2010 to promote less toxic regimens and those requiring fewer pills each day.

Researchers in the U.S. recently evaluated differences in adherence and hospitalizations depending on the number of antiretroviral pills taken each day.1 They assessed whether having to take fewer pills improved adherence and clinical outcomes in patients living with HIV.

The study found that patients taking a single pill each day had significantly better adherence when compared with patients taking multiple pills a day. Approximately 47 percent of patients taking a single daily pill achieved adherence rates of 95 percent or more, compared to 41 percent of patients on two pills and 34 percent on three or more pills a day. Furthermore, patients with at least 95 percent adherence had significantly lower rates of hospitalization. As the results show, achieving high levels of adherence is difficult regardless of the treatment regimen. However, once-daily regimens correlate with the highest levels of adherence and therefore should be prioritized to improve the effectiveness of ART.

Girl taking medicine
A child in Cambodia takes her antiretrovirals.

Although the study was based in a high-income country, the results may be applicable for patients in Asia. Fixed-dose, once-daily combination antiretroviral pills are available in many Asian countries, with some in less expensive generic forms. Despite WHO recommendations and research findings validating the benefits of once-daily pills, many Asian countries continue to use regimens with twice-daily or multiple pills due to lower costs.

Asian countries need to make greater efforts to promote simpler once-daily ART regimens that can result in better long-term treatment outcomes.


1.  Paul E. Sax, Juliana L. Meyers, Michael Mugavero, and Keith L. Davis. Adherence to Antiretroviral Treatment and Correlation with Risk of Hospitalization among Commercially Insured HIV Patients in the United States, PLoS One. 2012;7(2):e31591. Epub 2012 Feb 24.