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Tybost

Cobicistat
Used for HIV Treatment
Used for HIV Treatment

Tybost (cobicistat) is a booster medication that is used to raise the medication levels of other HIV antiretrovirals (ARVs) in your body.

Reviewed by:
reviewer
Hope Chang, PharmD, AAHIVP
reviewer
Michelle Nguyen, PharmD
Last reviewed on October 31, 2020
BasicsSide effectsPros & consPharmacist tipsFAQsWarningsDosageCostAlternativesPricesMedicare
basics-icon

What is Tybost (cobicistat)?

What is Tybost (cobicistat) used for?

  • HIV treatment, in combination with Reyataz (atazanavir) or Prezista (darunavir) once daily

How Tybost (cobicistat) works

Tybost (cobicistat) slows down an enzyme in our liver called CYP3A4. CYP3A4 metabolizes a lot of medications. By slowing down this enzyme, Tybost (cobicistat) can raise the levels of HIV ARV medications metabolized by CYP3A4.

Drug Facts

Common BrandsTybost
Drug ClassHIV ARV
Controlled Substance ClassificationNot a controlled medication
Generic StatusNo lower-cost generic available
AvailabilityPrescription only
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What are the side effects of Tybost (cobicistat)?

The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.

Common Side Effects

  • Yellowing of the skin and eyes (6%)
  • Rash (5%)

Other Side Effects

  • Nausea
  • Diarrhea
  • Headache
  • High blood sugar

Source: FDA

The following side effects have also been reported

Side effects that you should report to your care team as soon as possible:

  • Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat
  • Kidney injury—decrease in the amount of urine, swelling of the ankles, hands, or feet
  • Yellowing skin or eyes

Side effects that usually do not require medical attention (report to your care team if they continue or are bothersome):

pros-and-cons

Pros and cons of Tybost (cobicistat)

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Pros

Raises the medication levels of other HIV ARVs

Available in combination tablets with many other HIV ARVs

Easy once daily dosing

Dose is the same for adults and children

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Cons

No activity against HIV

Can't be used with all the protease inhibitors; Can only be used with Reyataz (atazanavir) and Prezista (darunavir)

Interacts with many other medications

Not a good option for people with kidney problems who are also taking tenofovir

pharmacist-tips

Pharmacist tips for Tybost (cobicistat)

pharmacist

  • Take Tybost (cobicistat) with food and at the same time as the drug it is boosting (Reyataz or Prezista).

    • If you're familiar with HIV ARVs, you might notice that Tybost (cobicistat) acts a lot like Norvir (ritonavir). Even though both of these medications are boosters, they are not interchangeable. If Tybost (cobicistat) is prescribed as a single HIV ARV, and not in a HIV ARV combo, then it can ONLY be used with Reyataz (atazanavir) or Prezista (darunavir) once daily.

      • Talk to your healthcare provider before starting any new medications. Tybost (cobicistat) interacts with a lot of medications, and make the levels in your body too high. Also make sure to tell your providers if you stop taking Tybost (cobicistat). Your providers might have lowered the dose of your other medications to adjust for the interaction.

        • Keep your regularly scheduled provider visits and lab appointments. These make sure your HIV ARVs are working against the virus without causing harmful side effects.

          • Tybost (cobicistat) is not recommended for people who are pregnant. Make sure you talk to your healthcare provider about your plans for becoming pregnant or options for birth control. If you become pregnant while taking Tybost (cobicistat), continue to take it and schedule an appointment with your provider as soon as possible. Do not stop taking it on your own.

            faqs

            Frequently asked questions about Tybost (cobicistat)

            Is Tybost (cobicistat) a protease inhibitor?
            No, Tybost (cobicistat) is not a protease inhibitor. It doesn't work on the HIV virus, instead it works on your liver to raise the levels of other HIV ARVs.
            Why is Tybost (cobicistat) used as a booster?
            Booster medications are prescribed with HIV ARVs to slow down the body's metabolism of the HIV ARV. These booster medications can raise medication levels which results in fewer tablets you have to take everyday.
            Can Tybost (cobicistat) be taken alone?
            No, Tybost (cobicistat) should always be prescribed with Reyataz (atazanavir) 300 mg tablet or Prezista (darunavir) 800 mg tablet. The combination of these HIV ARVs is still not a full HIV regimen and needs to be taken with at least 2 other HIV ARVs.
            How do you take Tybost (cobicistat)?
            Tybost (cobicistat) should be taken at the same time as your Reyataz (atazanavir) 300 mg tablet or your Prezista (darunavir) 800 mg tablet once daily. Since the other medications need to be taken with food, Tybost (cobicistat) should be taken with food as well.
            Is Tybost (cobicistat) bad for your kidneys?
            Tybost (cobicistat) can't be taken with certain medications because the 2 medications together can cause kidney problems. It can also raise a lab test called serum creatinine, which is used to monitor your kidney health. This doesn't mean that the medication is damaging your kidney. Your provider will check your serum creatinine and kidney function before you start Tybost (cobicistat) and then continue to monitor it with your routine labs.
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            What are the risks and warnings for Tybost (cobicistat)?

            Tybost (cobicistat) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.

            risk-warning

            CHANGES IN KIDNEY FUNCTION

            • Risk factors: History of kidney damage | Taking Viread (tenofovir)

              Tybost (cobicistat) can cause kidney damage or changes to your kidney function blood tests. This is more common in people with a history of kidney damage and those taking the older verion of tenofovir as part of their HIV ARV regimen. Make sure to have routine labs drawn so your provider can monitor your kidney function.

              risk-warning

              DRUG INTERACTIONS

              • Risk factors: Taking other medications or supplements

                Tybost (cobicistat) interacts with a lot of medications. The interaction usually makes the level of the other medication too high, and can lead to serious or fatal side effects. There are also medications that can lower the amount of Tybost (cobicistat) in your body, which will also lead to lower amounts of HIV ARVs that are boosted by Tybost (cobicistat). Talk to your healthcare provider or pharmacist before starting or stopping any medications.

                risk-warning

                Tybost (cobicistat) WITH OTHER HIV ARVS

                Tybost (cobicistat) can be a great addition to your HIV ARV regimen, but it can't be used with all HIV ARVs. It is only approved with certain protease inhibitors: atazanavir (Reyataz) and once-daily darunavir (Prezista), NOT twice-daily darunavir. It also can't be used with many NNRTIs, like Sustiva (efavirenz). Even though it's a booster like Norvir (ritonavir), it can't be used in place of Norvir (ritonavir) in a regimen. You should never be prescribed a HIV ARV regimen that includes Tybost (cobicistat) and Norvir (ritonavir).

                dosage

                Tybost (cobicistat) dosage forms

                Typical dosing for Tybost (cobicistat)

                The typical dose is 150 mg once daily, at the same time as Reyataz (atazanavir) 300 mg or Prezista (darunavir) 800 mg with food.

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                How much does Tybost (cobicistat) cost?

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                alternatives

                What are alternatives to Tybost (cobicistat)?

                There are a number of medications that your doctor can prescribe in place of Tybost (cobicistat). Compare a few possible alternatives below.
                Tybost (cobicistat)
                Used for:

                • HIV treatment, in combination with Reyataz (atazanavir) or Prezista (darunavir) once daily

                $324.95 Lowest GoodRx priceView Prices
                Ritonavir (Norvir)
                Used for:

                • Treatment of HIV infection (taken with other antiretroviral medications)

                $40.57 Lowest GoodRx priceView Prices

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