What is the primary purpose of prescribing both ritonavir and cobicistat?

Ritonavir is widely used to boost the effect of other PIs by blocking the CYP3A4 drug-metabolizing enzyme, which breaks down PIs. Cobicistat has a similar effect on CYP3A4 but has no direct impact on HIV.

Is cobicistat a CYP3A4 inhibitor?

Cobicistat is generally considered to be an equipotent inhibitor of CYP3A4 and P-gp as ritonavir, and is co-formulated with the PIs darunavir and atazanavir and the integrase inhibitor elvitegravir.

What is the generic name for Norvir?

Ritonavir (Norvir) is a protease inhibitor and a booster medication. At high doses it stops the HIV virus from making copies of itself, and at low doses it raises the levels of other HIV ARVs.

When did Norvir go generic?

Antiretroviral Agents Norvir (ritonavir): The generic equivalent for Norvir, ritonavir, was released by West-Ward Pharmaceuticals Corporation, in March 2018. Ritonavir is an HIV protease inhibitor that is FDA-approved for the treatment of HIV-1 infections.

Who makes cobicistat?

Cobicistat is marketed by Gilead Sciences, Inc., as Tybost®.

What class of drug is cobicistat?

Cobicistat is in a class of medications called cytochrome P450 3A (CYP3A) inhibitors. It works by increasing the amount of atazanavir or darunavir in the body so that they can have a greater effect.

What is the difference between cobicistat and ritonavir?

Although cobicistat (150 mg once daily) and ritonavir (100 mg once daily) are interchangeable as boosters of drugs metabolized by CYP3A, 9 cobicistat is a more specific CYP3A inhibitor than ritonavir and has no inducing properties. Consequently, differences are expected in their interaction profiles with some co-medications.

Is ritonavir a strong inhibitor of cytochrome P450?

Cobicistat and ritonavir are equally strong inhibitors of cytochrome P450 (CYP) 3A4 and consequently were shown to be equivalent pharmacokinetic enhancers for elvitegravir and for the PIs atazanavir and darunavir.

Is ritonavir a CYP3A boost agent?

Ritonavir and its structural analogue cobicistat, being inhibitors of the CYP3A subfamily, are boosting agents that prolong the action of some antiretroviral medicines. [footnote 1]

What are the limitations of ritonavir as a booster drug?

Ritonavir has antiviral activity, which raises concern about the development of PI resistance if ritonavir is used as a booster in non-PI-containing regimens. In addition, ritonavir is poorly soluble, which limits its coformulation with other agents.