Combivir is a fixed-dose combination tablet comprising 150mg 3TC (lamivudine) and 300mg AZT (zidovudine) manufactured by GlaxoSmithKline. AZT and 3TC are both nucleoside reverse transcriptase inhibitors, which reduce the amount of HIV in the body. Combivir was the first tablet to combine more than one anti-HIV drug.

The standard dose of Combivir is one tablet twice a day, with or without food, in combination with at least one other anti-HIV drug. It is licensed for use in adults and children over twelve years of age. Its European license was granted in March 1998 and in the United States in September 1997.

Combivir was licensed following demonstration that it had similar anti-HIV effects to AZT (Retrovir) and 3TC (Epivir) taken separately, when they were combined with a protease inhibitor. In a study of 223 patients, success rates were similar in the two arms. However, fewer patients randomised to receive Combivir missed drug doses, probably due to the smaller number of pills that need to be taken every day^[1]. The efficacy of AZT and 3TC had already been demonstrated in previous studies.

Combivir is only recommended for use during pregnancy where the risks outweigh the benefits.

Generic versions of Combivir include Duovir, manufactured by Cipla. Ranbaxy and Aurobindo Pharma also produce generic combinations of AZT and 3TC.

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