Drug Information



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Brand Name
Prezcobix
Common Name
cobicistat - darunavir
How does this medication work? What will it do for me?

This combination product contains two medications: darunavir and cobicistat. These two medications are used in combination with other medications to treat human immunodeficiency virus (HIV) infection.

Darunavir is a protease inhibitor and works by blocking an enzyme called protease, which the virus needs to multiply. Cobicistat slows down the speed at which the body gets rid of darunavir. It is included in this medication to increase the amount of darunavir in your blood. By interfering with enzymes that are needed for HIV to multiply, cobicistat-darunavir lowers the amount of HIV in the blood. They may also help the immune system by increasing the number of CD4 (T) cells in the body. This medication does not cure AIDS and does not reduce the risk of passing HIV to others through sexual contact or blood contamination. It is used in combination with other anti-HIV medications to slow further growth or reproduction of HIV. It also seems to slow down the destruction of the immune system. This may help to delay the development of problems such as infections related to AIDS or HIV disease.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

How should I use this medication?

The recommended adult dose of cobicistat-darunavir is one tablet taken by mouth, once daily. Cobicistat-darunavir should be taken with food. This helps to increase the amount of medication that is absorbed by the body.

Swallow the tablets whole and do not break or crush them.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor.

If you miss a dose, and less than 12 hours have passed, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, in its original container, and keep it out of reach of children.

What form(s) does this medication come in?

Each pink, oval-shaped, film-coated tablet, debossed with "800" on one side and "TG" on the other side contains darunavir ethanolate equivalent to 800 mg of darunavir per tablet and 150 mg cobicistat. Nonmedicinal ingredients: silicified microcrystalline cellulose, crospovidone, hypromellose, and magnesium stearate; tablet film coating: Opadry® II Pink (polyethylene glycol, polyvinyl alcohol - partially hydrolyzed, talc, titanium dioxide, iron oxide red, iron oxide black).

Who should NOT take this medication?

Do not take this medication if you:

  • are allergic to darunavir, cobicistat or any ingredients of the medication
  • have severely decreased liver function
  • are taking certain other medications, including but not limited to
    • alfuzosin
    • amiodarone
    • apixaban
    • carbamazepine
    • colchicine (people with decreased kidney or liver function)
    • dabigatran
    • dronedarone
    • elbasvir/grazoprevir
    • ergot derivatives (e.g., dihydroergotamine, ergonovine, ergotamine, methylergonovine)
    • ivabradine
    • lidocaine
    • lomitapide
    • lovastatin
    • lurasidone
    • naloxegol
    • phenobarbital
    • phenytoin
    • pimozide
    • rifampin
    • rivaroxaban
    • salmeterol
    • sildenafil (for treatment of pulmonary arterial hypertension)
    • simvastatin
    • St. John's wort
    • ticagrelor
    • triazolam
What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • abdominal pain
  • diarrhea
  • headache
  • nausea
  • vomiting

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • changes in fat distribution (increased fat in the upper back and neck, breasts, and trunk; and loss of fat from the arms, legs, and face)
  • increased blood cholesterol, triglycerides
  • signs of infection (e.g., fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
  • signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
  • signs of pancreatitis (e.g., abdominal pain on the upper left side, back pain, nausea, fever, chills, rapid heartbeat, swollen abdomen)
  • skin rash
  • symptoms of high blood sugar (e.g., frequent urination, increased thirst, excessive eating, unexplained weight loss, poor wound healing, infections, fruity breath odour)

Stop taking the medication and seek immediate medical attention if any of the following occur:

  • signs of a serious allergic reaction (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)
  • signs of a severe skin reaction such as blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever or discomfort

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Allergy: Some people who are allergic to sulfonamide antibiotics also experience allergic reactions to darunavir. Before you take this medication, inform your doctor about any previous adverse reactions you have had to medications, especially sulfonamide antibiotics such as sulfamethoxazole-trimethoprim. Contact your doctor at once if you experience signs of an allergic reaction, such as skin rash, itching, difficulty breathing, or swelling of the face and throat.

Bleeding: Darunavir may cause a reduced number of platelets in the blood, which can make it difficult to stop cuts from bleeding. If you notice any signs of bleeding, such as frequent nosebleeds, unexplained bruising, or black and tarry stools, notify your doctor as soon as possible. Your doctor will order routine blood tests to make sure potential problems are caught early. The risk of bleeding may be increased in people who have hemophilia. Discuss any concerns you may have with your doctor.

Blood tests: Darunavir can cause changes in your blood test results, such as red blood cell count, platelet count, cholesterol level, and sugar level. Your doctor will explain these to you and monitor your blood levels.

Diabetes: Antiretroviral medications such as darunavir may increase blood sugar levels. If you have diabetes or are at risk for developing diabetes, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is required.

Fat redistribution: Over time, this medication may change how fat is distributed in your body and may change your body shape. You may notice increased fat in the upper back and neck, breasts, or around the back, chest, and stomach area. Or you may notice loss of fat from the legs, arms, and face. The long-term effects of this are not known.

Immune reconstitution inflammatory syndrome: This medication may cause immune reconstitution inflammatory syndrome, where signs and symptoms of inflammation from previous infections appear. These symptoms occur soon after starting anti-HIV medications and can vary. They are thought to occur as a result of the immune system improving and being able to fight infections that have been present without symptoms, such as pneumonia, herpes, or tuberculosis. Report any new symptoms to your doctor immediately.

Liver function: Liver disease or reduced liver function may cause this medication to build up in the body, causing side effects. If you have liver problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. Your doctor may want to test your liver function regularly with blood tests while you are taking this medication. People with severe liver disease should not take cobicistat-darunavir.

There have been reports of serious liver problems while taking darunavir. People with liver problems (including hepatitis B or hepatitis C infection) are at a risk of experiencing worsening of these problems while taking this medication. If you experience symptoms of liver problems (e.g., abdominal pain, persistent vomiting, feeling unwell, fever, itching, yellowing of the skin and eyes, dark urine), contact your doctor immediately.

Pancreatitis: This medication may cause inflammation of the pancreas (pancreatitis). If you have a history of or are at risk for developing pancreatitis, you should be closely monitored by your doctor while taking this medication. Discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is required.

If you develop signs of pancreatitis (e.g., upper left abdominal pain, back pain, nausea, fever, chills, rapid heartbeat, swollen abdomen), contact your doctor.

Skin rashes: This medication can cause skin rash, which is usually mild or moderate. However, darunavir can cause severe skin reactions. If you develop a skin rash with fever, fatigue, blisters, muscle aches, or sores in and around the mouth, stop taking this medication and contact your doctor immediately.

Stopping the medication: If you stop taking this medication, your HIV infection could get worse. Take the medication exactly as prescribed by your doctor, and do not stop taking the medication without checking with your doctor first.

Pregnancy: The medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: It is not known if darunavir or cobicistat pass into breast milk. People who have HIV infection are cautioned against breast-feeding because of the risk of passing HIV to a baby who does not have the infection.

Children: The safety and effectiveness of using this medication have not been established for children.

What other drugs could interact with this medication?

For a full list of interactions, use the Drug Interaction Checker available on the Drugs.com website.

If you are taking other medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

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