Lopinavir/ritonavir is the first fixed-dose combination of protease inhibitors approved by the FDA for the treatment of HIV infection. It is being marketed for use with other drugs in adults and children more than six months old. Lopinavir is a new drug available only in this combination. Ritonavir is often used with other protease inhibitors to raise their plasma concentrations.

View the Inhibitors and Inducers of CYP Enzymes, P-Glycoprotein, and Other Transporters tables

On December 22, 2021, the FDA issued an Emergency Use Authorization (EUA) for the investigational antiviral drug nirmatrelvir copackaged with the HIV-1 protease inhibitor ritonavir (Paxlovid – Pfizer) for oral treatment of mild to moderate COVID-19 in outpatients ≥12 years old who weigh at least 40 kg and are at high risk of progressing to severe disease, including hospitalization or death. Paxlovid was the first oral antiviral drug to be authorized in the US for treatment of COVID-19; Merck's oral antiviral drug molnupiravir was granted an EUA for treatment of COVID-19 on...

Three products are currently available in the US for treatment of high-risk,1 nonhospitalized adults with mild to moderate COVID-19: oral ritonavir-boosted nirmatrelvir (Paxlovid), IV remdesivir (Veklury), and oral molnupiravir (Lagevrio). Remdesivir is FDA-approved for such use; nirmatrelvir/ritonavir and molnupiravir are available under an FDA Emergency Use Authorization. Because the pivotal clinical trials of these products for outpatient use were conducted in patients who were not vaccinated against COVID-19, some clinicians have questioned whether they can benefit vaccinated...

Cobicistat, a pharmacokinetic enhancer that boosts levels of some HIV drugs but has no antiretroviral activity of its own, is now available alone as Tybost (Gilead) and in fixed-dose combinations with the protease inhibitors atazanavir (Evotaz — BMS) and darunavir (Prezcobix — Janssen) for treatment of HIV-1 infection. Both atazanavir and darunavir have traditionally been used in combination with the CYP3A inhibitor ritonavir (Norvir) to boost their serum concentrations, but neither is available in a fixed-dose combination with ritonavir.

Antiretroviral therapy is recommended for all HIV-infected patients, both to reduce the risk of disease progression and to prevent transmission of the virus to others. Various guidelines for treatment of HIV infection are available.

The FDA has approved elvitegravir (Vitekta – Gilead), an integrase strand transfer inhibitor (INSTI), for use with a protease inhibitor (PI) plus ritonavir and other antiretroviral drugs for treatment of HIV-1 infection in treatment-experienced adults. Elvitegravir is also available in a fixed-dose combination (Stribild) with the pharmacokinetic enhancer cobicistat and the nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) emtricitabine and tenofovir disoproxil fumarate (DF). A similar combination (Genvoya) that includes tenofovir alafenamide instead of tenofovir...

Tipranavir (Aptivus - Boehringer Ingelheim), a new protease inhibitor, has received accelerated approval from the FDA. It must be given with ritonavir (Norvir). The combination is indicated for use with other antiretrovirals to treat HIV infection in highly treatment-experienced adults who have ongoing viral replication or in those with HIV strains known to be resistant to multiple protease inhibitors.

Darunavir (Prezista - Tibotec), a new protease inhibitor, has received accelerated approval from the FDA for use in combination therapy of human-immunodeficiency virus (HIV) infection in previously treated adults. It is coadministered with low-dose ritonavir (Norvir), which increases its bioavailability.

The FDA has approved Viekira Pak (Abbvie), a fixed-dose combination of two new direct-acting antiviral agents (ombitasvir, paritaprevir) with the pharmacologic enhancer ritonavir in one tablet, co-packaged with a third new direct-acting antiviral agent (dasabuvir) in a second tablet, for oral treatment of chronic hepatitis C virus (HCV) genotype 1 infection. Genotype 1 is responsible for 70-80% of HCV infections in the US.