Trizivir is a three-in-one combination pill containing Retrovir (zidovudine or AZT), Epivir (lamivudine or 3TC), and Ziagen (abacavir). Putting more than one drug in a single tablet means you get to take fewer pills each day and may have lower insurance co-payments.

Trizivir is made up of HIV drugs from a class called nucleoside reverse transcriptase inhibitors (NRTIs), also known as nucleoside analogs or “nukes.”

The NRTIs block reverse transcriptase, a protein that HIV needs to make more copies of itself. This may slow down HIV disease.

The Food and Drug Administration (FDA) has approved Trizivir for use alone or in combination with other HIV drugs for the treatment of HIV infection in adults and adolescents over 12 years of age.

Trizivir comes as a tablet that contains:

• 300 milligrams (mg) of Retrovir
• 150 mg of Epivir
• 300 mg of Ziagen

The dose is one tablet twice daily.

You can take Trizivir with food or on an empty stomach, but taking it with food may cut down on nausea or other side effects.

Trizivir may be used by itself or with other medications to treat HIV. However, Trizivir on its own may not be potent enough to control viral load for a prolonged period of time. This is especially true in people who start out with higher viral loads (above 100,000 copies) or resistance to some of the drugs contained in Trizivir.

It is probably best to use Trizivir in combination with drugs from other classes, such as the non-nucleoside reverse transcriptase inhibitors (NNRTIs) or protease inhibitors (PIs).

You should not take Trizivir if you weigh less than 88 pounds.

You should not take Trizivir if you have experienced a hypersensitivity reaction to Ziagen (see description of hypersensitivity reaction in “Side Effects” section).

Speak to your doctor if you have liver, kidney, or pancreas problems, or anemia.

As with all HIV drugs, it is important to take Trizivir as prescribed. Missing or skipping doses can cause your blood levels of the drug to fall too low and resistance can develop. When your virus becomes resistant to an HIV medication, that drug may stop working.

Trizivir can be used if you’re just starting on treatment.

Trizivir can be used if you’ve been on treatment before; however, it is not clear how well Trizivir works for people who are already resistant to Retrovir, Epivir, or Ziagen.

Your doctor can run a resistance test to help determine whether the drugs in Trizivir are likely to work for you.

Some of the drugs in Trizivir cross the blood-brain barrier (which protects the brain and spinal cord), so it may be able to fight HIV in the brain.

If your virus develops resistance to the drugs in Trizivir then it may stop working or not work as well for you. You also may not get as much benefit from the other NRTIs.

Sometimes taking more than one medication can cause drug interactions. Taking certain drugs (including methadone and ribavirin) with Trizivir can change the amount of each drug in your blood. Your doctor may need to adjust the doses of your drugs to avoid under- or overdosing.

Some drugs should not be taken with Trizivir, such as Retrovir, Epivir, Ziagen, Combivir, Zerit (stavudine or d4T), Emtriva (emtricitabine or FTC), Epzicom, Truvada, and Hivid (zalcitabine or ddC). You should also avoid using alcohol while taking Trizivir.

Several other medications can make the side effects of Trizivir worse. Be sure your doctor knows about all the medications you are taking (including over-the-counter, prescription, street drugs, and herbs), even if you only use them occasionally.

For more information and additional resources to check interactions between the particular drugs you are taking, see our info sheet on drug interactions.

Trizivir is associated with the same side effects as the drugs it contains. However, the side effects are likely to be temporary and go away as your body adjusts to the medication. If you are experiencing any of the side effects listed below, call your doctor for advice. Do not just stop taking your medication.

• Nausea
• Vomiting
• Diarrhea
• Loss of appetite
• Headaches
• Fatigue (unusual tiredness)
• Insomnia (trouble falling or staying asleep)
• Rash

More serious side effects:

• Hypersensitivity reaction: About 8 percent of people who take Ziagen—which is part of Trizivir—develop a very serious, potentially fatal side effect called a hypersensitivity (allergic) reaction. Signs to watch for include fever; skin rash; severe nausea, vomiting, or abdominal pain; cough, sore throat, or difficulty breathing. If you experience any of these symptoms, call your doctor immediately. If your doctor has you stop taking Trizivir because of a suspected hypersensitivity reaction, do not take Trizivir, Epzicom, or Ziagen ever again. All fatal hypersensitivity reactions have happened when someone re-started the drug after discontinuation.
• Low white blood cell count (neutropenia) or low red blood cell count ( anemia).
• Myopathy (muscle damage) – this can make your muscles feel achy and weak.
• An increase of lactic acid in the blood ( lactic acidosis), an enlarged and fatty liver, and liver failure, have been reported in people using NRTIs. Lactic acidosis is a rare but potentially fatal side effect. Symptoms include nausea, vomiting, or stomach pain; feeling very weak and tired; shortness of breath.
• Lipodystrophy, which may include elevated blood sugar (glucose), elevated lipid levels ( cholesterol and triglycerides), and fat gain or loss in certain areas. The exact causes of lipodystrophy are not known, but may include HIV and/or HIV drugs. It is unclear if the drugs in Trizivir will cause or impact symptoms of lipodystrophy. For more information on lipodystrophy, see our info sheet.

If you are experiencing persistent, unusual, or serious side effects, call your doctor right away.

Trizivir has been studied in both men and women. Its effectiveness and side effects seem very similar in both men and women. But some research suggests that women are more likely than men to develop liver problems and the rare but very serious side effect, lactic acidosis, while taking NRTI drugs.

The drugs in Trizivir (Retrovir, Epivir, and Ziagen) have been studied in many women (see the fact sheets on these separate drugs for more information).

There is still controversy about whether Trizivir should be used alone, especially by people with a high viral load. A study of Trizivir (ACTG 5095) was recently stopped early because it did not work as well as drug regimens that contained Sustiva (efavirenz). This study included 19 percent women, or about 218 women out of 1,147 total participants.

But for some people, Trizivir may still be the right choice. A study of lipodystrophy (ESS40002) that included half women found that Trizivir was less likely to cause increased blood fat levels than drug regimens that contained Viracept (nelfinavir). This small study was unusual because it included 50 percent women (about 129 women out of 258 total participants).

In this study, women were less likely than men to develop abnormal blood fat levels, but among people with very low HIV viral loads, the drug did not appear to work as well in women as in men.

A European study called Trizal also found that people who switched to Trizivir from a PI- or NNRTI-based drug regimen had decreased cholesterol levels. This study included 20 percent women, or about 41 women out of 209 total participants.

Retrovir greatly reduces transmission of HIV from mother to child. Retrovir and Epivir have been used during pregnancy without any significant negative effect to mother or baby; however, long- term effects on the child are not known.

There have been no formal studies on the use of Ziagen or Trizivir during pregnancy. Check with your doctor about the best treatment options for you and your baby if you are thinking of getting pregnant.

Click this link for more information about pregnancy.

A lower dose formulation of Epivir, one of the components of Trizivir, is used to treat hepatitis B (HBV) infection. Get tested for hepatitis B before you start taking Trizivir to treat HIV.

If you are co-infected with HIV and HBV, speak to your doctor about treatment options. In addition, if you are taking Trizivir for HIV treatment, discontinuing the drug may result in worsening hepatitis symptoms.

People who are starting HIV treatment for the first time may develop Immune Reconstitution Syndrome or IRS (also called Immune Reconstitution Inflammatory Syndrome or IRIS). IRS can happen as a result of the immune system getting stronger and responding to an HIV-related infection such as Mycobacterium avium infection (MAC), cytomegalovirus (CMV), Pneumocystis jirovecii pneumonia (PCP), or tuberculosis (TB). People may have been treated for these infections in the past or not even know they have them. If you notice any unusual symptoms soon after starting HIV drugs for the first time, let your doctor know right away so you can be evaluated and, if necessary, treated.

1		National Institute of Allergy and Infectious Diseases. (2003). Clinical advisory: Important interim results from a phase III, randomized, double-blind comparison of three protease-inhibitor-sparing regimens for the initial treatment of HIV infection ( AACTG Protocol A5095).
2		Opravil, M., et. al. (2002). A randomized trial of simplified maintenance therapy with abacavir, lamivudine, and zidovudine in human immunodeficiency virus infection. Journal of Infectious Diseases, 185(9). 1251-1260.
3		Podzamczer, D., et. al. (2002). A randomized, open, multicenter trial comparing Combivir plus nelfinavir or nevirapine in HIV-infected naïve patients (the COMBINE study). 40th Interscience Conference on Antimicrobial Agents and Chemotherapy. Toronto, Canada. Abstract 694.