Trizivir (lamivudine/3TC + zidovudine/AZT + abacavir)

August 2007     View PDF     En español
Reprinted from www.aidsmeds.com, US

What is Trizivir?
Trizivir is an anti-HIV medication. It is in a category of HIV medicines called nucleoside reverse transcriptase inhibitors (NRTIs). Trizivir prevents HIV from entering the nucleus of healthy T-cells. This prevents the cells from producing new virus and decreases the amount of virus in the body.

Trizivir is marketed by GlaxoSmithKline. It was approved by the U.S. Food and Drug Administration (FDA) for use by people living with HIV in 2000.

Trizivir is a combination of three previously approved drugs: 300mg of Retrovir (AZT), 150mg of Epivir (3TC), and 300mg of Ziagen (abacavir). Trizivir should be prescribed by a healthcare provider for patients who need to take all three drugs. For patients only taking AZT and 3TC, a combination tablet called Combivir is available. Also, any of these three drugs can be purchased individually for use in combination with other anti-HIV drugs.

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What is known about Trizivir?
Trizivir is taken twice daily, one tablet in the morning and one tablet in the evening, with or without food. It is approved by the FDA for use with or without other HIV medications.

Trizivir should not be any more or less effective than Retrovir, Epivir, and Ziagen taken as separate pills together. However, it is considered to be a much more convenient way of taking these three anti-HIV drugs.

For HIV-positive adults beginning anti-HIV drug therapy for the first time, Trizivir—used without other HIV medications—is listed as a “possible” treatment option by the United States Department of Health and Human Services in its treatment guidelines. This means that it can be used, but because of lingering concerns about effectiveness and/or safety, it is considered to be inferior to “preferred” or “alternative” drug combinations. The use of Trizivir without other HIV medications is only recommended when a preferred or alternative protease inhibitor (PI)- or a non-nucleoside reverse transcriptase inhibitor (NNRTI)-based regimen cannot be used because of side effects or significant drug-drug interactions.

See the “What is known about...” sections of Retrovir, Epivir, and Ziagen for information about possible drug resistance.

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What about drug interactions?
Trizivir should not be taken at the same time as Emtriva or Truvada (containing Viread and Emtriva). This is because the Epivir in Trizivir and Emtriva are very similar and it is not believed that combining these two anti-HIV drugs will make a regimen any more effective against the virus.

See the “What about drug interactions?” sections of sections of Retrovir, Epivir, and Ziagen.

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What about side effects?
A rare but potentially serious side effect of Retrovir (AZT), one of the three drugs in Trizivir, is myopathy (damage to the muscles, including the heart). People who use Retrovir for a long period of time, meaning several years, are at the greatest risk for myopathy. General symptoms of myopathy include weakness of limbs, usually proximal (located close to the center of the body).

Bone marrow problems, such as decreased production of red blood cells and/or white blood cells, can occur in people talking Retrovir, one of the three active drugs in Trizivir. Contact your doctor immediately if you develop unusual fatigue, pale skin, sore throat, fever, or chills, which may be signs of bone marrow problems.

An important side effect that doctors and patients need to be aware of is “hypersensitivity.” Approximately 5 percent of people who take Ziagen (abacavir), one of the three medications in Trizivir, are allergic to it. This can be serious and generally requires that Trizivir be stopped, and that Trizivir or Ziagen should not be taken again. A hypersensitivity reaction usually appears during the second week of therapy, but it can take as long as six weeks to notice any symptoms. The most common symptoms are fever and rash, followed by headaches, stomach upset, feeling sick or tired, sore throat, cough, and shortness of breath. These symptoms usually get worse over time and it is important that you report them to your doctor immediately. If you need to stop Trizivir because of this hypersensitivity reaction, you will still be able to take Retrovir and Epivir, the two other drugs in Trizivir.

An inexpensive laboratory test is available to look for an inherited gene, called HLA-B*5701, that has been linked to the hypersensitivity reaction in HIV-positive people taking Trizivir. While not all people with this gene experience an allergic reaction while taking Trizivir, most do. In turn, if you are tested and found to have this gene, Trizivir (or other medications containing abacavir) should either be avoided or used with caution. If you and your doctor are thinking about starting Trizivir or another abacavir-containing medication for the first time, be sure to discuss this genetic test.

Lactic acidosis, which can be fatal, and severe liver problems have been reported in people taking nucleoside reverse transcriptase inhibitors (NRTIs), including Retrovir, Epivir, and Ziagen, the three active drugs in Trizivir. Contact your doctor immediately if you experience nausea, vomiting, or unusual or unexpected stomach discomfort; weakness and tiredness; shortness of breath; weakness in the arms and legs; yellowing of the skin or eyes; or pain in the upper stomach area.

Anti-HIV drug regimens containing NRTIs, including Trizivir, can cause increased fat levels (cholesterol and triglycerides) in the blood, abnormal body-shape changes (lipodystrophy; including increased fat around the abdomen, breasts, and back of the neck, as well as decreased fat in the face, arms, and legs), and diabetes.

If you have hepatitis B and HIV and plan to stop taking Trizivir, your doctor might want to frequently check your liver enzymes after stopping treatment. This is because the Epivir in Trizivir is also active against the hepatitis B virus (HBV). If Epivir is stopped abruptly, it can cause liver disease to “flare” and damage the liver.

See the “What about side effects?” sections of Retrovir, Epivir, and Ziagen for additional possible side effects.

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Can pregnant women take Trizivir?
Trizivir is classified by the FDA as a pregnancy category C drug. Pregnancy category C means that animal studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks. HIV-positive women who become pregnant should discuss the benefits and possible side effects of anti-HIV treatment to help protect their babies from HIV.

It is not known whether Trizivir passes into breast milk and what effect they may have on a nursing baby. To prevent transmission of the virus to uninfected babies, it is recommended that HIV-positive mothers not breast-feed.

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What should I tell my doctor before taking Trizivir?
Before taking this medication, tell your doctor if you have: kidney disease; liver disease (including hepatitis B); or low blood cell counts (anemia or low white blood cells).

Be sure to tell your doctor if you’ve ever taken Trizivir, Epzicom, or Ziagen in the past. If you stopped these medications in the past because of an allergic reaction, you should not take Trizivir or any medication that contains Ziagen.

Tell your doctors and pharmacists about all medicines you take. This includes prescription medications, over-the-counter products, or herbal/natural remedies.

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Where can I learn more about clinical trials of Trizivir?
If you would like to find out if you are eligible for any clinical trials that include Trizivir, there is an interactive website run by ACRIA, the AIDS Community Research Initiative of America.

Another useful service for finding clinical trials is AIDSinfo.nih.gov, a site run by the U.S. National Institutes of Health. They have “health information specialists” you can talk to at their toll-free number at 1-800-HIV-0440 (1-800-448-0440).

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