Combivir is a combination of two drugs: 300mg of Retrovir (zidovudine) and 150mg of Epivir (lamivudine). Combivir should be prescribed by a healthcare provider for patients who need both of these drugs. Both of these drugs can still be purchased individually for use in combination with other HIV drugs.
Combivir must be combined with at least one other HIV drug, usually a protease inhibitor (PI) or a non-nucleoside reverse transcriptase inhibitor (NNRTI).
Combivir should not be taken at the same time as Emtriva or Truvada (containing Viread and Emtriva). This is because the Epivir in Combivir is very similar to Emtriva, and it is not believed that combining these two HIV drugs will make a regimen any more effective against the virus. Similarly, Combivir should not be taken at the same time as Retrovir, Epivir, Epzicom (containing Ziagen and Epivir) or Trizivir (containing Ziagen, Epivir and Retrovir).
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.
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 two active drugs in Combivir. Contact your doctor immediately if you develop unusual fatigue, pale skin, sore throat, fever, or chills, which may be signs of bone marrow problems.
A rare but potentially serious side effect of Retrovir, one of the two drugs in Combivir, 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).