atazanavir + stavudine + didanosine

This drug is a **combination of three antiretroviral agents**: **atazanavir**, **stavudine**, and **didanosine**, used primarily in the treatment of HIV-1 infection. Atazanavir is a protease inhibitor that prevents the cleavage of HIV Gag-Pol polyproteins, leading to the production of immature, non-infectious viral particles. Stavudine and didanosine are nucleoside reverse transcriptase inhibitors (NRTIs) that act as chain terminators after incorporation into viral DNA by reverse transcriptase, preventing viral replication. This combination has been studied in antiretroviral-naive patients as part of combination therapy regimens for HIV, but is not marketed as a fixed-dose combination. Each agent has specific pharmacokinetics, adverse effects, and interaction profiles; didanosine and stavudine, particularly, are associated with increased risks of lactic acidosis and peripheral neuropathy, especially when used together[1][4][8]. Administration requires careful attention to drug-drug interaction timing, particularly between atazanavir and didanosine[2][4][6]. These drugs are not commonly co-formulated and their combination is less recommended in newer HIV guidelines due to toxicity concerns.