Prezcobix (Darunavir + Cobicistat) - HIV Drug Information

Prezcobix pill front and back
Photograph courtesy Janssen Therapeutics

Prezcobix (darunavir + cobicistat) is a fixed-dose combination antiretroviral drug used in the treatment of HIV. The two drug components contained in Prezcobix are individually marketed at Prezista (darunavir) and Tybost (cobicistat).

The single-pill, co-formulated tablet offers easy, once-daily dosing, with the cobicistat component effectively boosting and sustaining by plasma concentration of Prezista in the body.

Prezcobix was approved by the U.S. Food and Drug Administration (FDA) in January 2015 for both new and experienced adult patients with HIV-1 infection.


The film-coated oblong tablet, comprised of 800mg of darunavir and 150mg of cobicistat, is pink in color and embossed with "TG" on one side and "800" on the other.


One tablet is taken daily with food. Prezcobix cannot be used alone but must be taken in combination with one or more accompanying antiretroviral drug(s).


Before starting, patients should be tested to assess their estimated creatinine clearance as Prezcobix can potentially impair renal (kidney) function, most often in patients with known or undiagnosed renal dysfunction. When coadministered with Viread (tenofovir)—a drug also known to cause renal impairment in some—it is recommended that patients be tested for estimated creatinine clearance, urine glucose, and urine protein.

It is also recommended that treatment-experienced patients, particularly those exposed to HIV protease inhibitors, be provided genetic resistance testing before taking Prezcobix. If genotypic testing is not available, Prezcobix should be avoided for anyone previously exposed to HIV protease inhibitors.

Common Side Effects

In Phase III human clinical studies, a number of potential drug side effects have been identified when using Prezcobix. The most common adverse events, reported in 5% or less of patients, were:

  • Diarrhea
  • Nausea
  • Rash
  • Headache
  • Abdominal pain
  • Vomiting

Drug Contraindications

Prezcobix should not be taken with the following drugs or herbal supplements:

  • Anti-anginal medication: Ranexa
  • Anti-arrhythmic medications: Multaq
  • Anti-cholesterol medications: Mevacor, Zocor
  • Anti-gout medications: Uroxatral
  • Anti-hypertension medications: Revatio
  • Antipsychotic medications: Latuda, Orap
  • Cancer medications: Camptosar, Campto
  • Ergot-containing anti-migraine derivatives: DHE 45, Ergotrate, Hydergine, Migranal
  • Rifampin-based anti-tuberculosis medications: Mycobutin, Rifater, Rifamate, Rimactane, Rifadin, Priftin
  • Sedatives: Dormicum, Halcion, Hypam, Hyponvel, Trilam, Versed
  • St. John's Wort

Antiretroviral Drug Interactions

The use of Prezcobix with following antiretroviral drugs may result either in the loss of therapeutic effect of the accompanying drug or the increased risk of side effects:

  • Crixivan (indinavir) should not be coadministered with Prezcobix.
  • Videx (didanosine) should be taken either one hour before or one hour after taking Prezcobix.
  • Intelence (etravirine) should not be coadministered with Prezcobix.
  • Viramune (nevirapine) should not be coadministered with Prezcobix
  • Selzentry (maraviroc) dosage should be adjusted to 150mg twice daily if coadministered with Prezcobix.

Other Interactions or Considerations

  • Inform your doctor of any known or suspected renal (kidney) condition you may have before starting Prezcobix.
  • Erectile dysfunction medication (Viagra, Levitra, Cialis) should be used with caution as the cobicistat component in Prezcobix can boost the level of adverse side effects, including visual disturbances, hypotension, and priapism (painful, sustained erections). It is recommended that Viagra dosage is decreased to no more than 25mg in 48 hours; Levitra dosage is decreased to no more than 2.5mg  in 72 hours, and Cialis dosage is decreased to no more than 10mg in 72 hours.​
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Article Sources
  • Bristol-Myers Squibb. "PREZCOBIX - FULL PRESCRIBING INFORMATION." New York, New York