Prezcobix (Darunavir and Cobicistat) – Oral

What Is Prezcobix?

Prezcobix (darunavir and cobicistat) is a prescription medication used with other human immunodeficiency virus-1 (HIV-1) drugs to treat HIV-1 in adults and children weighing at least 88 pounds. It does not cure HIV but slows down and prevents the virus from causing acquired immunodeficiency syndrome (AIDS).

Prezcobix contains two active ingredients: darunavir and cobicistat. Darunavir works by blocking the HIV protease enzyme from cutting Gag-Pol polyproteins in infected cells into smaller functional viral proteins and enzymes. This process stops infected cells from growing and infecting other healthy cells in the body.

Cobicistat is a strong cytochrome P450 3A4 (CYP3A4) inhibitor. Because darunavir is rapidly metabolized in the liver, cobicistat is used to boost darunavir's effects by competing with its metabolism in the liver.

Prezcobix is available by prescription as a tablet to take by mouth.

Drug Facts

Generic Name: Darunavir and cobicistat

Brand Name(s): Prezcobix

Drug Availability: Prescription

Administration Route: Oral

Therapeutic Classification: Antiretroviral agent, protease inhibitor

Available Generically: No

Controlled Substance: N/A

Active Ingredient: Darunavir and cobicistat

Dosage Form(s): Tablet

What Is Prezcobix Used For?

Prezcobix is used along with other HIV-1 medications to treat HIV-1 in adults and children weighing at least 88 pounds. It contains the prescription medications darunavir and cobicistat.

HIV is a virus that attacks the body's immune system. While there is no cure for HIV, antiretroviral therapy (ART) can reduce the amount of the virus in your body. However, if left untreated, HIV can lead to AIDS.

How to Take Prezcobix

You should take Prezcobix with food on a regular basis (once per day) as prescribed by your healthcare provider. Prezcobix should not be the only medication used to treat HIV-1.

Do not stop taking Prezcobix without talking with your healthcare provider first. Stopping this medication, even briefly, may make it harder to treat your HIV-1 infection. Read all instructions that come with this medication.


Store Prezcobix in a closed container at room temperature (between 68 and 77 degrees Fahrenheit), away from heat, moisture, and direct light. Do not store it in the bathroom.

What Are the Side Effects of Prezcobix?

This is not a complete list of side effects and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your healthcare provider. You may report side effects to the Food and Drug Administration (FDA) at or 800-FDA-1088.

Common Side Effects

Common side effects of Prezcobix include:

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

Severe Side Effects

Call your healthcare provider immediately if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and symptoms can include the following:

  • Increased bleeding risk in people with hemophilia (an inherited bleeding disorder)
  • Immune system changes
  • High blood sugar
  • Changes in body fat
  • Severe life-threatening skin reactions including Stevens-Johnson syndrome, toxic epidermal necrolysis (TEN), or drug rash with eosinophilia and systemic symptoms (DRESS): Call your healthcare provider immediately if you develop any skin changes along with fever, tiredness, muscle or joint pain, blisters or skin lesions, mouth sores or ulcers, and red or inflamed eyes such as conjunctivitis (pink eye).

Report Side Effects

Prezcobix may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program website or by phone (800-332-1088).

Dosage: How Much Prezcobix Should I Take?

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The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (tablets):
    • For treatment of HIV infection:
      • Adults and children weighing at least 40 kilograms (kg)—One tablet once a day. Each tablet contains 800 milligrams (mg) of darunavir and 150 mg of cobicistat.
      • Children weighing less than 40 kg—Use and dose must be determined by your doctor.


Do not take this medication during pregnancy. It could harm a developing fetus. You should not breastfeed while using this medication, as HIV can be spread to nursing babies through breast milk. Although HIV treatment can decrease viral levels in the body, and therefore decrease the likelihood of passing HIV through breastfeeding, this does not mean there is no risk.

Tell your healthcare provider immediately if you become pregnant. Birth control pills may not work as well with Prezcobix, so it is important to use another form of birth control, like condoms, along with your birth control.

Missed Dose

If you miss your dose of Prezcobix, take your dose as soon as you remember. If your next dose is in less than 12 hours, wait until then and take a regular amount. Do not take extra medicine to make up for a missed dose.

Overdose: What Happens If I Take Too Much Prezcobix?

An overdose with Prezcobix is not common. Generally, an overdose of Prezcobix is addressed by treating the symptoms and monitoring the individual's vital signs.

Symptoms of overdose can include:

  • Nausea and vomiting
  • Redistribution of body fat (lipodystrophy)
  • Elevated liver enzymes
  • High blood sugar (hyperglycemia)
  • Rash
  • Stevens-Johnson syndrome (rare disorder of the skin and mucous membranes)
  • Liver failure (rare)

What Happens If I Overdose on Prezcobix?

If you think you or someone else may have overdosed on Prezcobix, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking  Prezcobix, call 911 immediately.


Drug Content Provided and Reviewed by IBM Micromedex®

It is very important that your doctor check your progress at regular visits, especially during the first few weeks that you take this medicine, to make sure it is working properly. Blood and urine tests may be needed to check for any unwanted effects.

This medicine should not be used together with alfuzosin (Uroxatral®), carbamazepine (Tegretol®), cisapride (Propulsid®), dronedarone (Multaq®), elbasvir/grazoprevir (Zepatier®), ivabradine (Corlaonor®), lomitapide (Juxtapid®, Lojuxta®), lovastatin (Mevacor®), lurasidone (Latuda®), naloxegol (Movantik®, Moventig®), oral midazolam (Versed®), phenobarbital (Luminal®), phenytoin (Dilantin®), pimozide (Orap®), ranolazine (Ranexa®), rifampin (Rifadin®, Rimactane®), sildenafil (Revatio®), simvastatin (Zocor®), St. John's wort, triazolam (Halcion®), or ergot medicines (eg, dihydroergotamine, ergotamine, methylergonovine, Cafergot®, Ergomar®, Wigraine®). Do not use this medicine together with colchicine (Colcrys®) if you have kidney or liver disease.

Using this medicine while you are pregnant can harm your unborn baby. Birth control pills may not work as well to prevent pregnancy when used with this medicine. Use another form of birth control (eg, condoms, spermicide) along with your pills to keep from getting pregnant during treatment with this medicine. If you think you have become pregnant while using this medicine, tell your doctor right away.

Check with your doctor right away if you have pain or tenderness in the upper stomach, pale stools, dark urine, loss of appetite, nausea, unusual tiredness or weakness, or yellow eyes or skin. These could be symptoms of a serious liver problem.

Serious skin reactions (eg, Stevens-Johnson syndrome, toxic epidermal necrolysis, drug rash with eosinophilia and systemic symptoms, and acute generalized exanthematous pustulosis) can occur with this medicine. Check with your doctor right away if you have any of the following symptoms: severe rash, blistering, peeling, or loosening of the skin, chills, cough, diarrhea, itching, joint or muscle pain, red skin lesions, often with a purple center, skin rash, sore throat, sores, ulcers, or white spots in the mouth or on the lips, or unusual tiredness or weakness.

This medicine may increase your risk for kidney problems, including acute kidney failure or Fanconi syndrome (when used together with tenofovir DF). Check with your doctor right away if you have changes in how much you urinate, decreased mental sharpness, nausea, vomiting, loss of appetite, or muscle twitches or cramps.

This medicine may increase blood sugar levels. Check with your doctor if you notice a change in the results of your blood or urine sugar tests.

This medicine may cause you to have excess body fat. Tell your doctor if you notice changes in your body shape, such as an increased amount of fat in the upper back and neck, or around the chest and stomach area. You might also lose fat from the legs, arms, and face.

Your immune system may get stronger when you start taking HIV medicines. Tell your doctor right away if you notice any changes in your health. Sometimes the immune system will start to fight infections that were hidden in your body, such as pneumonia, herpes, or tuberculosis. Autoimmune disorders (eg, Graves' disease, polymyositis, Guillain-Barré syndrome, and autoimmune hepatitis) may also occur.

This medicine does not decrease the risk of transmitting the HIV infection to others through sexual contact or by contaminated blood. Make sure you understand and practice safe sex, even if your partner also has HIV. Avoid sharing needles with anyone.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or non-prescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

What Are Reasons I Shouldn’t Take Prezcobix?

You should not take Prezcobix if you have severe liver or kidney disease.

Tell your healthcare provider if you have:

  • Kidney disease
  • Liver disease
  • Diabetes
  • Hemophilia
  • An allergy to sulfa drugs

Prezcobix can cause the following:

  • Liver problems
  • Serious skin reactions
  • New or worsening kidney problems
  • High blood sugar levels, which could become permanent
  • Increased risk of bleeding

Do not take Prezcobix if you are taking any of the following medications:

Taking these medications with Prezcobix can cause serious health problems, as well as death.

What Other Medications Interact With Prezcobix?

Prezcobix may interact with the following medications:

Talk to your healthcare provider if you are using any of the above-listed medications. Your healthcare provider may suggest alternative medications or change your dose. This is not an all-inclusive list of drugs that can interact with Prezcobix. Please discuss any new prescription or over-the-counter (OTC) medications, vitamins, or herbal supplements with your healthcare provider or pharmacist.

What Medications Are Similar?

Other combination HIV-1 medications that include a protease inhibitor include:

  • Evotaz (atazanavir and cobicistat), a two-drug combination of an HIV-1 protease inhibitor (atazanavir) and CYP3A inhibitor (cobicistat) used with ART agents in adults and children weighing at least 77 pounds
  • Lexiva (fosamprenavir calcium) with Norvir (ritonavir)
  • Kaletra (lopinavir and ritonavir), an HIV-1 protease inhibitor used with other ART agents in adults and children 14 days and older

Frequently Asked Questions

  • What is Prezcobix used for?

    Prezcobix is a prescription medication used along with other medications to treat HIV-1 infection in adults and children weighing at least 88 pounds. It is a combination medication containing darunavir and cobicistat.

  • How does Prezcobix work?

    Darunavir is a protease inhibitor. It works to treat HIV by preventing the HIV protease enzyme from cutting Gag-Pol polyproteins in infected cells into smaller functional viral proteins and enzymes. This process stops infected cells from growing and infecting other healthy cells in the body.

    Cobicistat is a strong CYP3AA inhibitor. It helps boost darunavir's effects by competing with the metabolism of darunavir in the liver.

  • What are the most common side effects of Prezcobix?

    Common side effects associated with Prezcobix include rash, abdominal (stomach) pain, diarrhea, nausea and vomiting, and headache.

How Can I Stay Healthy While Taking Prezcobix?

Although Prezcobix can help keep your HIV under control, it will not prevent you from transmitting the virus to others. Continue to practice safer sex, even if your partner also has HIV. Your healthcare provider will perform regular lab tests to monitor how well Prezcobix works for you.

Here are other tips to keep in mind if you are living with HIV:

  • Do not share needles or other items that may have blood or body fluids on them.
  • Follow up and attend scheduled medical appointments while taking your medication.
  • Take your medications every day and exactly as prescribed. Try using adherence strategies such as pill boxes, reminder apps, and medication diaries to track your schedule.
  • Talk to your healthcare provider before starting new prescription or OTC medications, vitamins, or herbal supplements. Prezcobix has many different interactions that could affect how well it works or cause detrimental side effects.

If you are having trouble affording your HIV treatment, consider asking your healthcare team or the medication's manufacturer about co-pay and patient assistance programs.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food and Drug Administration. Prezcobix label.

  2. Deeks ED. Cobicistat: a review of its use as a pharmacokinetic enhancer of atazanavir and darunavir in patients with HIV-1 infection. Drugs. 2014;74(2):195-206. doi:10.1007/s40265-013-0160-x

  3. National Institutes of Health. FDA-approved HIV medicines.

  4. Bristol Myers Squibb. Evotaz label.

  5. DailyMed. Label: Lexiva- fosamprenavir calcium tablet, film coated. Lexiva-fosamprenavir, calcium suspension.

  6. AbbVie. Kaletra label.