This product is used with other HIV medications to help control HIV infection. It helps to decrease the amount of HIV in your body so your immune system can work better. This lowers your chance of getting HIV complications (such as new infections, cancer) and improves your quality of life. This product is a combination of two different drugs: darunavir and cobicistat. Darunavir belongs to a class of drugs known as protease inhibitors. Cobicistat is used to increase ("boost") the levels of darunavir.

Brand name:Prezcobix

Active Ingeridents:Darunavir/Cobicistat

Company Name: Janssen

Package:30 Tablets

Strength :Darunavir 800mg + Cobicistat 150mg

Mechanism of action:


Darunavir is a HIV protease inhibitor which prevents HIV replication by binding to the enzyme's active site, thereby preventing the dimerization and the catalytic activity of the HIV-1 protease. Darunavir selectively inhibits the cleavage of HIV encoded Gag-Pol polyproteins in virus-infected cells, which prevents the formation of mature infectious virus particles. Structual analyses suggests that the close contact that darunavir has with the main chains of the protease active site amino acids (Asp-29 and Asp-30) is an important contributing factor to its potency and wide spectrum of activity against multi-protease inhibitor resistant HIV-1 variants. Darunavir can also adapt to the changing shape of a protease enzyme because of its molecular flexibility. Darunavir is known to bind to two distinct sites on the enzyme: the active site cavity and the surface of one of the flexible flaps in the protease dimer.


Cobicistat is a mechanism-based inhibitor of cytochrome P450 3A (CYP3A) isoforms. Inhibition of CYP3A-mediated metabolism by cobicistat increases the systemic exposure of CYP3A substrates atazanavir and darunavir and therefore enables increased anti-viral activity at a lower dosage. Cobicistat does not have any anti-HIV activity on its own.

Dosage and Administration:

Use Prezcobix (Darunavir/Cobicistat) as directed by your doctor. Check the label on the medicine for exact dosing instructions

  • An extra patient leaflet is available with Prezcobix (Darunavir/Cobicistat). Talk to your pharmacist if you have questions about this information.

  • Take Prezcobix (Darunavir/Cobicistat) by mouth with food.

  • If you also take didanosine, take it at least 1 hour before or 2 hours after Prezcobix (Darunavir/Cobicistat).

  • Ask your health care provider any questions you may have about how to use Prezcobix (Darunavir/Cobicistat).

Side effects:

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome:

Diarrhea; headache; nausea; stomach pain; vomiting.


Before taking Prezcobix (Darunavir/Cobicistat), tell your doctor or pharmacist if you are allergic to either of the medications; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: liver disease (including hepatitis B, C), kidney disease, a certain bleeding problem (hemophilia), diabetes, heart problems (coronary artery disease, heart attack), lipid problems (high cholesterol or triglycerides/fats).


Store Prezcobix (Darunavir/Cobicistat) at room temperature, between 68 and 77 degrees F (20 and 25 degrees C). Store away from heat, moisture, and light. Keep Prezcobix (Darunavir/Cobicistat) out of the reach of children and away from pets.


Prezcobix (Darunavir/Cobicistat) is a prescription drug and should be used under proper medical guidance and advice. The information provided here is for general educational purposes only and does not constitute medical or pharmaceutical advice which should be sought from qualified medical and pharmaceutical advisers.