Emtricitabine (Emtriva) is a new nucleoside reverse transcriptase inhibitor that was recently approved by the U.S. Food and Drug Administration (FDA) for treating HIV-1 infection. Like some other HIV drugs, it is taken once a day and always with another anti-HIV medication.

How It Works
Nucleoside reverse transcriptase inhibitors (NRTIs) are antiretroviral medications. They prevent the human immunodeficiency virus (HIV) from multiplying. When the amount of virus in the blood is kept at a minimum, the immune system has a chance to recover and grow stronger.

Why It Is Used
Treatment with three or more antiretroviral medications (highly active antiretroviral therapy, or HAART) is a standard of care for HIV infection.

The recommended combination is two nuccleoside reverse transcriptase inhibitors (NRTIs) with one protease inhibitor (PI) or efavirenz (a nonnucleoside reverse transcriptase inhibitor, or NNRTI). Two PI combinations are also used, either alone or with NRTIs or an NNRTI.

How Well It Works
Combination therapy that includes two or more NRTIs plus an NNRTI or a PI:

Reduces viral loads, which can lead to stable or increased CD4+ cell counts (a sign that the immune system is still able to fight off opportunistic infections).

Decreases the number and severity of opportunistic infections.
Reduces or prevents the occurrence of drug resistance.
Prolongs life.

Antiretroviral therapy can also decrease symptoms of HIV infection, such as fever, weakness, and weight loss.

ZDV, either alone or in combination with other antiretrovirals, reduces the risk of the spread of HIV from an infected mother to her baby. 2

The rate at which antiretrovirals decrease viral loads is affected by: 2
CD4+ cell counts at the beginning of treatment.
Viral load at the beginning of treatment.
The dosage of the medications.
Whether the medications are taken exactly as prescribed.
Whether antiretroviral medications have been taken before.
Whether any opportunistic infections are present.
?BR>Side Effects
All of the NRTI medications can cause changes in the distribution of body fats, or a more serious side effect called lactic acidosis; lactic acidosis causes rapid breathing, excessive sweating, cool and clammy skin, sweet-smelling breath, abdominal pain, nausea or vomiting, and coma. In addition, each medication may be associated with its own unique side effects.

Abacavir
A serious, potentially life-threatening allergic reaction occurs in a small number of people who take abacavir. Symptoms of this allergic reaction may include:
Fever.
Muscle aches.
Diarrhea.
Rash.
Nausea or vomiting.
Abdominal pain.
Severe fatigue.
Cough.

Didanosine
Side effects of didanosine may include:
Inflammation of the pancreas (pancreatitis), which can lead to abdominal pain and vomiting. This side effect is more common in people who drink alcohol heavily.
Numbness, tingling, and painful sensations in the hands and feet (peripheral neuropathy).
Nausea or vomiting.
Diarrhea.

Lamivudine
Side effects of lamivudine are uncommon but may include:
Kidney problems.
Reduced numbers of red blood cells (anemia).
Reduced numbers of a certain type of white blood cell (neutropenia).

Stavudine
Side effects of stavudine may include numbness, tingling, or pain in the hands and feet (peripheral neuropathy).

Zalcitabine
Side effects of zalcitabine may include:
Inflammation of the pancreas (pancreatitis).
Sores in the mouth (stomatitis).
Numbness, tingling, or pain in the hands and feet (peripheral neuropathy).

Zidovudine
Side effects of zidovudine may include:
Nausea or vomiting.
Vague feeling of weakness or discomfort (malaise).
Headache.
Reduced numbers of red blood cells (anemia).
Severe fatigue.
Insomnia.

Abacavir, zidovudine, and lamivudine combinations
Side effects of any combination of abacavir, zidovudine, and lamivudine include side effects of all three medications, such as:
Fever.
Cough.
Nausea or vomiting.
Diarrhea.
Abdominal pain.
Severe fatigue.
Rash.

Emtricitabine
Side effects of emtricitabine can include:
Headache.
Diarrhea.
Nausea.
Rash.
Skin discoloration.
Serious side effects of emtricitabine can include:

Serious liver problems.
Flare-ups of hepatitis B in those who already have it.
Report all side effects to your health professional at your next visit. He or she can adjust your dose or give you other medications to reduce side effects. Some mild side effects, such as nausea, improve as your body adjusts to the medication.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About
Factors to consider when choosing a medication combination include:

The medications' abilities to reduce your viral load.
The likelihood that the virus will develop resistance to a certain class of medication. If you have already been treated with an antiretroviral medication, you may already know whether you are resistant to medications in that class.
Side effects and your willingness to tolerate them.
Many people think that antiretroviral medications always have severe side effects. In fact, only a few people experience severe side effects.

Like several other anti-HIV medications, emtricitabine is taken only once a day. If you have trouble taking multiple medications throughout the day, you may want to ask your health professional whether Emtriva is right for you. Emtriva is always combined with at least 2 other anti-HIV medications to treat HIV or AIDS.