Although the integrase inhibitor Isentress (raltegravir) is recommended for people going on treatment for the first time, it's the only first line drug that's taken twice, not once, a day. In an effort to simplify the dosing, a study compared taking Isentress twice a day vs. once a day.

Unfortunately, the 48-week results showed that fewer people who took Isentress once a day (83%) had undetectable viral loads below 50 copies compared to those who took it twice a day (89%). The reason for this is likely because the drug is quickly processed out of the body. Although this difference appears slight it was statistically significant, thereby showing once a day does not provide an equal level of HIV suppression that twice a day does, especially in people who started treatment at viral loads over 100,000.