Trizivir is a fixed-dose combination tablet comprising 150mg 3TC (lamivudine), 300mg abacavir and 300mg AZT (zidovudine) 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.

Ranbaxy make a generic version of this combination, called Abac-ALZ.

Trizivir is not recommended for use during pregnancy, and should only be used where the tablet’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 (Retrovir) and 3TC (Epivir) 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].

Taking the single Trizivir pill produces similar levels of AZT, 3TC and abacavir in the blood to the three drugs 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).