Sustiva (efavirenz) is both safe and no less effective at fighting HIV when the standard dose is reduced by a third. Researchers conducted a global study of 630 HIV-positive participants who started their first antiretroviral regimen with either 600 or 400 milligrams of Sustiva plus Truvada (tenofovir and emtricitabine), which are the components of Atripla.  

After 48 weeks of treatment, 94 percent of those on the cut dose and 92 percent of those on the standard dose achieved a suppressed viral load—essentially equivalent results.

While reducing the Sustiva dose didn't affect the number of adverse side effects or improve the drug's tolerability, fewer people stopped treatment because of central nervous system reactions in the lower-dose group.

According to the study's lead author, Rebekah Puls, PhD, of the University of New South Wales in Australia, the dose reduction translates to a savings of $20 per year per person in poorer nations.

Considering a new global push to greatly increase HIV treatment worldwide, Puls reflects, “That's a huge savings. That's literally millions and millions of dollars.”