August 22, 2009
The drugs in Truvada are called nucleoside analog reverse transcriptase inhibitors, or nukes. These drugs block the reverse transcriptase enzyme. This enzyme changes HIV’s genetic material (RNA) into the form of DNA. This has to occur before HIV’s genetic code gets inserted into an infected cell’s own genetic codes
There are no absolute rules about when to start antiretroviral therapy (ART). You and your health care provider should consider your CD4 cell count, your viral load, any symptoms you are having, and your attitude about taking ART. Fact Sheet 404 has more information about guidelines for the use of ART.
If you take Truvada with other antiretroviral drugs, you can reduce your viral load to extremely low levels, and increase your CD4 cell counts. This should mean staying healthier longer.
Truvada has not been tested in people under 18 years old and people who have hepatitis B infection. They should not take Truvada without careful discussion with their health care provider.
Some people with HIV had their hepatitis B get worse after they stopped taking emtricitabine, which is part of Truvada. Get tested for hepatitis B before you start taking Truvada to treat HIV. If you have hepatitis B and stop taking Truvada, your health care provider should carefully monitor your liver function for several months.
Truvada provides two drugs in one pill. It can be more convenient to use Truvada than some other combinations of drugs. This could mean fewer missed doses and better control of HIV.
Truvada is not recommended for use as part of a triple-nucleoside regimen.
Sometimes, if your virus develops resistance to one drug, it will also have resistance to other ARVs. This is called "cross-resistance."
Resistance can develop quickly. It is very important to take ARVs according to instructions, on schedule, and not to skip or reduce doses.
Truvada can be taken with food, or between meals. If you have kidney problems, you may need to take Truvada less often.
The most common side effects of Truvada are the same as with tenofovir (Viread) and emtricitabine (Emtriva). They include headache, nausea, vomiting, rash and loss of appetite. In some people, tenofovir can increase creatinine and transaminases. These are enzymes related to the kidneys and liver. High levels can indicate damage to these organs.
Tenofovir can reduce bone mineral density (see Fact Sheet 557). Calcium or vitamin D supplements may be helpful. This is especially true for people with osteopenia or osteoporosis. Fact Sheet 551 has more information on fatigue.
Levels of lactic acid in the blood (lactic acidosis, see Fact Sheet 556) increase in some people taking nucleoside analog drugs. Liver problems including "fatty liver" may also occur.
In rare cases, people taking emtricitabine had some limited changes in skin color.
Truvada should not be taken with 3TC (lamivudine, Epivir).
Truvada increases levels of ddI (Videx). The dose of ddI taken with Truvada should be reduced to 250 mg for people weighing 60 kg (132 lbs) or more. There is no information on ddI dosing for people weighing less than this.
Truvada should not be used with tenofovir (Viread) or emtricitabine (Emtriva, FTC) or with drugs containing lamivudine (Epivir, 3TC) including Combivir, Trizivir or Epzicom.
There are no data on interactions between emtricitabine and methadone. Tenofovir does not affect blood levels of methadone.