Trizivir (AZT/3TC/abacavir)

Trizivir is a fixed-dose combination tablet containing 150mg 3TC (lamivudine, Epivir), 300mg abacavir and 300mg AZT (zidovudine, Retrovir). It is manufactured by GlaxoSmithKline. 3TC, abacavir and AZT are nucleoside reverse transcriptase inhibitors (NRTIs), which reduce the amount of HIV in the body.

The standard dose of Trizivir is one tablet twice a day, with or without food. It is licensed for use in adults and children over twelve years of age. It was approved in the United States in November 2000 and in the European Union in March 2001.

Trizivir is not recommended for use during pregnancy, and should only be used when the drug's benefits outweigh its risks.

Trizivir was originally proposed as an easy and potent triple-drug regimen based on the results of two studies, showing equivalence to combinations of AZT and 3TC with either indinavir (Crixivan) or nelfinavir (Viracept).1,2 However, a large study known as ACTG A5095 demonstrated that Trizivir is a less potent first-line combination than the combination of AZT, 3TC, and efavirenz (Sustiva).3 Consequently, guidelines published by the British HIV Association in June 2003 recommended that Trizivir should not be used as a first-line regimen based on available evidence.

Despite the lack of potency, improved adherence and short-term tolerance are regarded as benefits of the triple NRTI regimen.4

The single Trizivir pill produces the same blood levels of AZT, 3TC and abacavir as are found when the three drugs are taken separately.5

For more information on 3TC, abacavir and AZT, including side-effects, resistance and drug interactions, see 3TC (lamivudine, Epivir), abacavir (Ziagen) and AZT (zidovudine, Retrovir).

References

  1. Staszewski S et al. Abacavir-lamivudine-zidovudine vs indinavir-lamivudine-zidovudine in antiretroviral naive HIV-infected adults: a randomized equivalence trial. JAMA 285: 1155-1163, 2001
  2. Matheron S et al. An open label study to compare efficacy and safety of the triple nucleoside analog combination Combivir / abacavir versus a protease inhibitor containing regimen in antiretroviral naïve adults. CNAF3007/Ecreuil. 13th International AIDS Conference, Durban, abstract WeOrB605, 2000
  3. Gulick RM et al. Triple-nucleoside regimens versus efavirenz-containing regimens for the initial treatment of HIV-1 infection. N Engl J Med 350: 1850-1861, 2004
  4. Opravil M et al. A randomized trial of simplified maintenance therapy with abacavir, lamivudine, and zidovudine in human immunodeficiency virus infection. J Infect Dis 185: 1251-1260, 2002
  5. Yuen GJ et al. Abacavir / lamivudine / zidovudine as a combined formulation tablet: bioequivalence compared with each component administered concurrently and the effect of food on absorption. J Clin Pharmacol 41: 277-288, 2001