September 15, 2012
Combination medications are pills or tablets that contain more than one medication to fight HIV. They are listed in the tables below. Pharmaceutical companies have been working hard to make their medications easier to take. Part of this effort has been to combine more than one medication in a single pill. These combinations are referred to as fixed-dose combinations, or FDCs.
The first FDC to treat HIV was Combivir by ViiV Healthcare*. Combivir contains two nucleoside analog reverse transcriptase inhibitors. This was followed by Trizivir, also by ViiV Healthcare, which includes 3 nukes. Some antiviral products are only available outside the US through the US President's Emergency Plan for AIDS Relief (PEPFAR.) For more information, see Fact Sheet 925 or www.pepfar.gov.
Be sure that you do not take a combination medication along with any of its components! For example, do not take Truvada with tenofovir (Viread) or emtricitabine (Emtriva); do not take Combivir along with zidovudine (Retrovir) or lamivudine (Epivir.)
When some medications are taken by mouth, their levels in the blood are very low. For them to fight HIV, they have to be taken at high doses. Another possibility is to "boost" their blood levels. This is done by slowing down the processing (metabolism) of these drugs. A drug that slows down the metabolism is called a "PK booster." PK stands for pharmacokinetic. This refers to the way that medications are processed by the body.
The first PK booster used in HIV was ritonavir by Abbott. Ritonavir slows down the metabolism of many drugs by the liver. This increases the blood levels of some anti-HIV medications so that a lower dose can be taken. However, it can also increase blood levels of many other drugs. In some cases, this can cause a harmful overdose.
2. Combinations of a Non-Nucleoside Reverse Transcriptase Inhibitor and Reverse Transcriptase Inhibitors
NOTE: a small dose of ritonavir is used to boost blood levels of other protease inhibitors. The amount of ritonavir is not high enough to fight HIV.
(Note: a small dose of ritonavir or cobicistat is used to boost blood levels of the integrase inhibitor.)
NOTE: There are many combination medications approved as part of the US President's Emergency Plan for AIDS Relief. For more information, see www.fda.gov/oia/pepfar.htm.
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