TRIZIVIR

Basic Informations

Trizivir is an 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 CD4 cells. This prevents the cells from producing new virus and decreases the amount of virus in the body.

Trizivir is marketed by ViiV Healthcare. 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 (zidovudine), 150mg of Epivir (lamivudine), 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 zidovudine and lamivudine, a combination tablet called Combivir is available. For patients only taking abacavir and lamivudine, a combination tablet called Epzicom is available. Also, any of these three drugs can be purchased individually for use in combination with other HIV drugs.

Drugs 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.

Ziagen can increase the rate at which methadone, a drug often used to help manage symptoms of heroin withdrawal, is cleared from the body. If you are taking methadone and Ziagen at the same time, it might be necessary to increase your methadone dose.

Retrovir should not be combined with either Rebetol or Copegus, two brand-name versions of ribavirin. Ribavirin is an oral medication used to treat hepatitis C. Ribavirin affects the way Retrovir is broken down by the body into its active form, potentially make Retrovir less effective and more toxic.

Retrovir can interact with some medications used to treat TB, MAC and other bacterial infections. Rifadin (rifampin) and Mycobutin (rifabutin) can lower levels of Retrovir in the bloodstream, which can cause the drug to be less effective against HIV. If you need to take Rifadin or Mycobutin, it might be necessary to switch your Retrovir for another nucleoside reverse transcriptase inhibitor (NRTI) that does not interact with these drugs.

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.

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. These side effects of HIV drug therapy are reviewed in our lessons on Lipodystrophy, Facial Lipoatrophy, and Risks To Your Heart (Hyperlipidemia).

Taking medications like Trizivir that contain Ziagen may increase the risk of a heart attack. The reason for the increased risk associated with Ziagen, compared with other NRTIs, has not been established. The risk of a heart attack is highest among people living with HIV taking Ziagen who have other cardiovascular disease (CVD) factors, including high blood pressure, high lipids, diabetes, cigarette smoking, family history of CVD.

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.