sofosbuvir + ritonavir + atazanavir + emtricitabine + tenofovir disoproxil fumarate

This is a **combination regimen of five antiviral agents**: sofosbuvir (a nucleotide analog inhibitor of hepatitis C virus NS5B polymerase), ritonavir (a pharmacokinetic enhancer and HIV-1 protease inhibitor), atazanavir (an HIV-1 protease inhibitor), emtricitabine (an HIV-1 reverse transcriptase inhibitor, nucleoside class), and tenofovir disoproxil fumarate (an HIV-1 reverse transcriptase inhibitor, nucleotide class). This combination is sometimes investigated or used in **patients coinfected with HIV and hepatitis C**, combining direct-acting antiviral therapy for hepatitis C (sofosbuvir) with an optimized antiretroviral regimen (atazanavir/ritonavir + emtricitabine + tenofovir disoproxil fumarate) for HIV. Ritonavir acts mainly as a booster for atazanavir. **Coadministration increases exposure and potential toxicity of some agents—especially tenofovir—and requires close renal monitoring**. Clinical data mainly support the safety and utility of these agents in pairs or triplets; use of all five is complex and should only be undertaken when other alternatives are unavailable, and usually in a supervised, inpatient, or clinical trial setting[1][5].