3. 8 Why three or more drugs are used
Current HIV drugs are not powerful enough to fight HIV on their own.
But using several drugs in combination ART is strong enough. Using ART to bring viral load to undetectable levels prevents HIV replicating and controls HIV infection.
- When the first HIV drugs were developed (roughly 1987 to 1993), each drug was used as single drug treatment. From 1994 to 1996 combinations of two drugs were used. In both cases the benefits only lasted a few months or perhaps a year or two at the most. This was because HIV developed drug resistance to the drugs.
- Since 1996, ART has used three or more drugs together to treat HIV. This suppressed the virus to very low levels and the risk of drug resistance was dramatically reduced.
Some drugs combine several drugs into the same pill. Sometimes a whole combination is fitted into a once-daily pill.
In 2016, there are six full combinations in a single pill that are recommended in UK and US gudielines. There are several combinations of two-drug combinations to be used with other drugs.
Generic HIV drugs are also available in numerous single pill formulations. Some drug combinations are only available in generic formulations.
Although some studies reported good results using only a boosted protease inhibitor (PI/b), the results are not as good as with three-drug combinations.
In October 2015, several small studies reported results from using single therapy with the integrase inhibitor dolutegravir, or using dolutegravir plus lamivudine (3TC). Although these studies produced exciting results, further research is still needed.
Last updated: 1 January 2016.