Tybost – Cobicistat uses, dose and side effects


150 mg film-coated tablets

What Tybost is and what it is used for

Tybost contains the active substance cobicistat.

Tybost is used to treat infection by human immunodeficiency virus type 1 ( HIV -1 ), the virus that causes acquired immunodeficiency syndrome ( AIDS ). It is used in adults and adolescents aged 12 years and older who are infected with HIV and who:

  • weigh at least 35 kg (when Tybost is given together with atazanavir 300 mg) or
  • weighing at least 40 kg (when Tybost is given together with darunavir 800 mg).

Tybost acts as a booster of atazanavir or darunavir ( both of which are protease inhibitors ) to enhance their effect (see section 3 of this leaflet).

Tybost does not treat your HIV directly but works by boosting the levels of atazanavir and darunavir in the blood. It does this by slowing the breakdown of atazanavir and darunavir, which then remain longer in the body.

What you need to know before using Tybost

Do not use Tybost

  • if you are allergic to cobicistat or any of the other ingredients of this medicine (listed in section 6 of this leaflet).
  • If you are taking medicines containing any of the following:
  • alfuzosin used to treat enlarged prostate gland
  • amiodarone, and quinidine, used to correct irregular heartbeats
  • dabigatran used to prevent and treat blood clots
  • carbamazepine, phenobarbital, and phenytoin used to prevent seizures
  • rifampicin used to prevent and treat tuberculosis and other infections
  • dihydroergotamine, ergometrine, and ergotamine are used to treat migraine headaches
  • St. John’s wort ( Hypericum perforatum ), a natural remedy, is used for depression and mild anxiety
  • lovastatin, simvastatin, is used to lower the cholesterol level in the blood
  • pimozide, and lurasidone, used to treat abnormal thoughts or feelings
  • sildenafil is used to treat pulmonary arterial hypertension – a lung disease that makes breathing difficult
  • midazolam (administered orally), triazolam, used to help you sleep and/or reduce anxiety)

→If any of these apply to you, do not take Tybost and inform your doctor immediately.

Warnings and precautions

Your treatment with Tybost must be followed up by a doctor at all times.

You can still transmit HIV while taking this medicine, although the risk is reduced with effective antiretroviral therapy. Talk to your doctor about the precautions needed to avoid infecting other people. This medicine does not treat your HIV infection directly. You can still develop an infection or other diseases associated with HIV infection. You must have regular contact with your doctor.

Talk to your doctor before taking Tybost:

  • If you take another protease inhibitor. Tybost taken with atazanavir or darunavir should not be used with any other antiviral medicine that needs to be boosted.
  • Talk to your doctor or pharmacist if you have or have had kidney disease or if tests have shown that you have problems with your kidneys. Your doctor will carefully consider whether you should be treated with Tybost.
  • Talk to your doctor or pharmacist if you have or have had serious liver disease or if tests have shown that you have liver problems. Your doctor will carefully consider whether you should be treated with Tybost.

→If any of these apply to you, talk to your doctor before taking Tybost.

Children and young people

Do not give this medicine to children under 12 years of age, or who weigh less than 35 kg (or 40 kg), as explained in section 3 of this leaflet. The use of Tybost in children under 12 years of age or weighing less than 35 kg has not been studied.

Other medicines and Tybost

Tell your doctor or pharmacist if you are taking, have recently taken, or might take any other medicines. Tybost can affect or be affected by other substances. This can lead to the amount of Tybost or other medicines in the blood being affected. The medicines may then not work properly or any side effects may worsen. In some cases, the doctor may need to change the dose or check the amount of medicine in the blood.

Certain medicines should never be taken with Tybost.

These are under the heading “Do not take Tybost – If you take medicines that contain any of the following”.

Medicines used to treat HIV infection:

You should not take Tybost with other medicines that contain:

  • ritonavir
  • cobicistat
  • Talk to your doctor if you are taking
  • another protease inhibitor
  • efavirenz
  • etravirine
  • nevirapine
  • maraviroc

→Inform the doctor if you are taking any of these HIV medicines.

Other types of medicines:

  • ketoconazole , itraconazole, voriconazole, posaconazole and fluconazole , medicines used to treat fungal infections
  • clarithromycin and rifabutin, medicines used to treat bacterial infections such as tuberculosis
  • dasatinib, nilotinib, vinblastine, and vincristine, medicines used to treat cancer
  • corticosteroids include betamethasone, budesonide, fluticasone, mometasone, prednisone, and triamcinolone. These medicines are used to treat allergies, asthma, inflammatory bowel diseases, inflammatory conditions in the skin, eyes, joints, and muscles, and other inflammatory conditions. These drugs are usually taken orally, inhaled, injected, or applied to the skin or eye. If there are no alternatives, the drug should be used only after medical judgment and under close monitoring by your doctor for side effects of corticosteroids
  • metformin, a medicine used to treat type 2 diabetes
  • oral or implanted hormonal contraceptives used to prevent pregnancy
  • amlodipine, digoxin, diltiazem, disopyramide, felodipine, flecainide, lidocaine, metoprolol, mexiletine, nicardipine, nifedipine, propafenone, timolol and verapamil, drugs used to treat heart problems
  • bosentan, a drug used to treat pulmonary arterial hypertension
  • apixaban, edoxaban, rivaroxaban and warfarin , medicines used to prevent and treat blood clots
  • salmeterol, a medicine used to treat asthma
  • atorvastatin, fluvastatin, pitavastatin, pravastatin, and rosuvastatin, medicines used to lower blood cholesterol levels
  • sildenafil and vardenafil, drugs used to treat impotence, and tadalafil, a drug used to treat impotence and pulmonary hypertension
  • trazodone, a drug used to treat depression
  • ciclosporin, sirolimus, and tacrolimus, medicines used to control the body’s immune system after a transplant
  • buspirone, clorazepate, diazepam , estazolam, flurazepam, perphenazine, risperidone , thioridazine, or zolpidem, medicines used to treat disorders of the nervous system
  • colchicine, a medicine used to treat gout
  • clopidogrel, a medicine used to reduce the risk of blood clots

→Inform the doctor if you are taking any of these medicines.

→Tell the doctor if you are taking any of these or other medicines. You should not stop treatment without talking to your doctor.

Pregnancy and breastfeeding

If you are pregnant or breastfeeding, think you may be pregnant, or are planning to have a baby, consult your doctor or pharmacist before using this medicine.

  • Tell your doctor immediately if you are pregnant, think you may be pregnant, or are planning to have a baby. Pregnant women should not take Tybost with atazanavir or darunavir. The amount of this medicine in the blood may decrease during pregnancy, which may cause it to stop working properly.
  • Do not breastfeed during treatment with Tybost. It is unknown whether the active substance in this medicine can pass into human breast milk. If you are an HIV -infected woman, you should not breastfeed your infant to avoid transmission of HIV to the baby through breast milk.

Driving ability and use of machinery

Some patients reported dizziness when Tybost was taken at the same time as atazanavir or darunavir. If you are affected while taking Tybost, you should not drive a car or use any tools or machines.

Tybost contains para-orange aluminum lacquer (E110)

Tell the doctor if you are allergic to para-orange aluminum lacquer (E110).

Tybost contains para orange aluminum lacquer which can cause allergic reactions.

Ty cheese contains sodium

This medicine contains less than 1 mmol (23 mg) of sodium per tablet, i.e. it is almost ‘sodium-free’.

How to use Tybost

Always take this medicine as directed by your doctor. Ask your doctor or pharmacist if you are unsure.

The recommended dose for adults:

  • One tablet a day by mouth with food. You must not chew, crush or split the tablet.
  • Tybost must be taken together with atazanavir (300 mg) or darunavir (800 mg).

The recommended dose for adolescents aged 12 to under 18 years:

  • One tablet every day by mouth, in conjunction with food. The tablet must not be chewed, crushed, or split.
  • When Tybost is taken together with atazanavir (300 mg), adolescents must weigh at least 35 kg.
  • When Tybost is taken together with darunavir (800 mg), adolescents must weigh at least 40 kg.

Always take the dose prescribed by the doctor to ensure that the medicine is effective. Do not change the dose unless your doctor tells you to.

If you have taken too much Tybost

If you accidentally take more than the prescribed dose of Tybost, the risk of side effects with this medicine may increase (see section 4 of this leaflet).

Contact your doctor or nearest emergency department immediately for advice. Save the jar so you can easily describe what you have taken.

If you forget to take Tybost

You mustn’t miss a dose of Tybost.

If you miss a dose and notice it:

  • within 12 hours of the time, you usually take Tybost, you must take the tablet as soon as possible. The tablet must always be taken with food. Then take the next dose as usual in combination with atazanavir or darunavir.
  • 12 hours or more after the time you usually take Tybost, do not take the missed dose. Wait and take the next dose with food at its regular time.

Do not stop taking Tybost

Do not stop taking Tybost without talking to your doctor. If you stop taking Tybost and atazanavir or darunavir, it may seriously affect the success of future treatments prescribed by your doctor.

Make sure you always have enough Tybost so you don’t run out. When your supply of Tybost starts to run low, get more from your doctor or pharmacist.

If you have any further questions about this medicine, ask your doctor or pharmacist.

Possible side effects

Like all medicines, this medicine can cause side effects, although not everybody gets them. When treating HIV infection, it is not always possible to know which of the unwanted effects are caused by Tybost, by other medicines you are taking, or by the HIV disease. The following side effects may occur when Tybost is taken together with atazanavir.

Very common side effects are

(may affect more than 1 in 10 people)

  • nausea
  • yellow skin and/or yellow whites of the eyes (jaundice)

Common side effects are

(may affect up to 1 in 10 people )

  • high blood sugar ( hyperglycemia )
  • increased appetite, taste changes, dry mouth
  • headache, dizziness
  • vomiting, diarrhea, stomach ache, problems with digestion causing pain after eating ( dyspepsia ), feeling bloated, gas formation ( flatulence )
  • increased levels of bilirubin in the blood (hyperbilirubinemia)
  • rash
  • difficulty sleeping, abnormal dreams, sleepiness, tiredness

Less common side effects are

(may affect up to 1 in 100 people )

  • blood in the urine ( hematuria )
  • protein in the urine ( proteinuria )
  • Depression
  • itching
  • muscle pain, weakness
  • kidney stones are
  • fever
  • sleep disorder

For more information about the side effects of atazanavir or darunavir, see the package leaflets for these medicines.

How Tybost should be stored

Keep this medicine out of sight and reach of children.

Use before the expiry date which is stated on the can and carton after {EXP}. The expiration date is the last day of the specified month.

No special storage instructions.

Medicines must not be thrown into the drain or among the household waste. Ask the pharmacist how to dispose of medicines that are no longer used. These measures will help to protect the environment.

Contents of the packaging and other information

Contents declaration

The active substance is cobicistat. One film-coated tablet contains 150 mg of cobicistat.

Other ingredients are

Tablet core

Croscarmellose sodium, magnesium stearate, microcrystalline cellulose (E460), silicon dioxide (E551).

Film coating

Para-orange aluminum lake (E110), macrogol 3350 (E1521), polyvinyl alcohol (partially hydrolyzed) (E1203), talc (E553), titanium dioxide (E171), yellow iron oxide (E172) (see section 2 of this leaflet).

Appearance and package sizes of the medicine

Tybost film-coated tablets are orange, round, biconvex tablets, debossed on one side with “GSI” and plain on the other side.

Tybost is supplied in cans containing 30 tablets (with desiccant in the form of silica gel in a sachet or container which must be kept in the can to protect the tablets from moisture). The desiccant (silica gel) is in a separate sachet or container and should not be swallowed.

The following pack sizes are available: Outer cartons containing 1 bottle of 30 film-coated tablets and 90 (3 bottles of 30) film-coated tablets. Not all pack sizes may be marketed.

Marketing authorization holder and manufacturer

Marketing Authorisation Holder

Gilead Sciences Ireland UC


County Cork, T45 DP77



Gilead Sciences Ireland UC

IDA Business & Technology Park


County Cork


Contact the representative of the marketing authorization holder if you want to know more about this medicine.

België/Belgique/BelgienGilead Sciences Belgium SPRL-BVBATel/Tel: + 32 (0) 24 01 35 50LithuaniaGilead Sciences Poland Sp. z o. iPhone: + 48 22 262 8702
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