atazanavir + ritonavir + tenofovir disoproxil fumarate + famotidine

This is a four-drug combination regimen consisting of three antiretroviral agents—atazanavir, ritonavir, and tenofovir disoproxil fumarate—used for the treatment of HIV infection, along with famotidine, an H2-receptor antagonist used to reduce gastric acid. Atazanavir is a protease inhibitor that blocks the HIV protease enzyme, preventing viral replication. Ritonavir acts as a pharmacokinetic booster by inhibiting cytochrome P450 3A4 (CYP3A4), thereby increasing plasma concentrations of atazanavir. Tenofovir disoproxil fumarate is a nucleotide reverse transcriptase inhibitor that inhibits HIV reverse transcriptase and prevents viral DNA synthesis. Famotidine reduces stomach acid by blocking histamine H2 receptor in gastric parietal cells; it is sometimes co-administered to manage gastrointestinal side effects or comorbid conditions requiring acid suppression. The combination has been studied due to potential drug-drug interactions: both tenofovir and famotidine can reduce plasma concentrations of atazanavir[1][2][3]. Dose adjustments or specific timing strategies are recommended when these drugs are used together to maintain effective antiretroviral activity[1][2][3]. This regimen is primarily indicated for the treatment of HIV infection.

Brand names

Reyataz (atazanavir)Norvir (ritonavir)Viread (tenofovir disoproxil fumarate)Pepcid (famotidine)

Other names

atazanavir sulfateritonavir oral solutionfamotidine oral tablet