Tybost: Uses, Side Effects and Dosage

What is Tybost used for?

Tybost is used with another medicine called atazanavir (Reyataz^®) to treat Human Immunodeficiency Virus-1 (HIV) infection in adults. The safety and effect of Tybost has not been established in children under age 18.

How does Tybost work?

Tybost is a medicine called a pharmacokinetic enhancer (or “booster”). Tybost slows the enzyme that breaks down atazanavir (Reyataz) in the body. This causes a “boost” or an increase of atazanavir levels in the blood. Atazanavir will then stay in the body for longer. Tybost does not directly treat your HIV infection.

What are the ingredients in Tybost?

Medicinal ingredients: cobicistat.

Non-medicinal ingredients: croscarmellose sodium, iron oxide yellow, magnesium stearate, microcrystalline cellulose, polyethylene glycol, polyvinyl alcohol, silicon dioxide, sunset yellow FCF (FD&C Yellow #6) aluminum lake, talc, titanium dioxide.

Tybost comes in the following dosage forms:

Tablets: 150 mg. The tablets are orange, round, biconvex, and film-coated, debossed with “GSI” on one side and plain-faced on the other side.

Do not use Tybost if:

• You are allergic to Tybost or any of its ingredients. (Read also “What are the ingredients in Tybost?” above.)
• You are taking any medicines listed in this pamphlet under “Drugs that must not be taken with Tybost” or “If you are taking Tybost, you should not take:” sections.

To help avoid side effects and ensure proper use, talk to your healthcare professional before you take Tybost. Talk about any health conditions or problems you may have, including if you:

• Are taking another protease inhibitor. Tybost taken with atazanavir should not be used with another antiviral medicine that requires boosting.
• Have other medical conditions. Let your doctor know if you have other medical conditions, especially liver problems (including hepatitis B or C virus infection), or kidney problems.

Other warnings you should know about:

Redistribution or accumulation of body fat has been seen in people taking antiretroviral medications such as Tybost. This can include central obesity, dorsocervical fat enlargement (buffalo hump), peripheral wasting (loss of muscle), facial wasting (loss of fat in face), breast enlargement, and “cushingoid appearance”.

Using Tybost with atazanavir does not cure HIV infection or AIDS. The long-term effects of Tybost are not known at this time. People taking Tybost with atazanavir (Reyataz) may still get opportunistic infections or other conditions that happen with HIV infection. Opportunistic infections are infections that develop because the immune system is weak. Some of these conditions are pneumonia, herpes virus infections, and Mycobacterium avium complex (MAC) infections. It is very important that you see your doctor regularly while taking Tybost.

Using Tybost with atazanavir (Reyataz) has not been shown to reduce the risk of passing HIV to others through sexual contact or blood contamination. Continue to practice safe sex. Use latex or polyurethane condoms to lower the chance of sexual contact with any body fluids such as semen, vaginal secretions, or blood. Do not re-use or share needles.

Pregnancy:

If you are pregnant or plan to become pregnant, talk to your doctor before you take this medicine. The effects of Tybost during pregnancy are not known. Avoid pregnancy while taking Tybost. Tell your doctor if you become pregnant while taking Tybost:

Pregnancy Registry: There is a pregnancy registry for women who take antiviral medicines during pregnancy. This registry collects information about your health and your baby’s health. If you become pregnant while taking Tybost, talk with your doctor about taking part in this registry.

Breastfeeding:

If you are breast-feeding or plan to breast-feed: Do not breast-feed if you have HIV because of the chance of passing the HIV virus to your baby. It is not known if Tybost can pass through your breast milk and harm your baby. If you are a woman who has or will have a baby, talk with your doctor about the best way to feed your baby.

If you are taking other medicines: Some medicines can interact when taken together, including prescription and non-prescription medicines, herbal products and dietary supplements (see “Drugs that must not be taken with Tybost” and “If you are taking Tybost, you should not take:” section

Tybost should not be used in combination with another medicine called quetiapine. This is because serious and possibly life-threatening reactions can occur. This includes severe sedation and coma. If it is necessary for you to take Tybost with quetiapine your doctor may need to monitor you and adjust the dose of quetiapine.

Tell your healthcare professional about all the medicines you take, including any drugs, vitamins, minerals, natural supplements or alternative medicines.

Drugs that must not be taken with Tybost (contraindicated):

• alfuzosin hydrochloride (Xatral^®)
• apixaban (Eliquis^®), rivaroxaban (Xarelto^®)
• astemizole* (Hismanal^®) or terfenadine* (Seldane^®)
• carbamazepine (Tegretol^®)
• cisapride* (Propulsid^®)
• colchicine
• dronedarone (Multaq^®)
• drospirenone/ ethinyl estradiol (Yaz^®)
• elbasvir/grazoprevir (Zepatier^®)
• ergot-containing medicines: dihydroergotamine, ergonovine, ergotamine, methylergonovine, such as Migranal^® and others.
• indinavir* (Crixivan^®)
• irinotecan
• lomitapide (Juxtapid™)
• lovastatin* (Advicor^®, Mevacor^®)
• lurasidone (Latuda^®)
• midazolam* (Versed^®), when taken by mouth
• nevirapine
• phenobarbital, phenytoin (Dilantin^®)
• pimozide (Orap^®)
• rifampin (Rofact^®)
• ranolazine* (Ranexa^®)
• salmeterol (Serevent^®)
• sildenafil (Revatio^®), when used for treating lung problems
• simvastatin (Zocor^®)
• St. John’s Wort (Hypericum perforatum) or products containing St. John’s Wort
• triazolam

*Not available in Canada

If you are taking Tybost, you should not take:

• antiplatelets such as clopidogrel (Plavix^®)
• medications that may affect your kidneys and have not discussed this with your doctor.
• any other HIV protease inhibitors: eg, saquinavir (Invirase^®), tipranavir (Aptivus^®), or fosamprenavir (Telzir^®), lopinavir (Kaletra^®), darunavir (Prezista^®).
• other medicines that contain cobicistat (GENVOYA^®, Prezcobix^®, STRIBILD^®, Symtuza^®).
• ritonavir (Kaletra^®, Norvir^®)

Tell your doctor before using Tybost if you are taking these drugs:

The dosage of Tybost or the dosage of the following drugs may need to be changed:

• antivirals such as didanosine, delavirdine, efavirenz, maraviroc
• antiarrhythmic drugs (for the heart) such as amiodarone, bepridil, flecainide (Tambocor^®), quinidine
• anticancer drugs such as dasatinib, nilotinib, vinblastine, vincristine
• anticoagulants such as warfarin, dabigatran (Pradaxa^®), edoxaban (Lixiana^®)
• anticonvulsant drugs such as clonazepam
• antidepressants such as trazadone, desipramine
• antifungals such as itraconazole (Sporanox^®), ketoconazole (Nizoral^®), voriconazole (Vfend^®)
• antimycobacterials such as rifabutin, rifapentine
• antipsychotics such as risperidone, pimozide, perphenazine, quetiapine
• beta-blockers such as timolol, metoprolol (Lopresor^®)
• calcium channel blockers (for the heart) such as amlodipine (Norvasc^®), felodipine, verapamil
• corticosteroids such as betamethasone, budesonide, fluticasone (Flonase^®), mometasone, and triamcinolone
• HCV protease inhibitors such as boceprevir*
• H2 receptor antagonists (acid reducers) such as famotidine
• HMG-COA reductase inhibitors (lowers cholesterol) such as atorvastatin and rosuvastatin
• hormonal contraceptives such as norgestimate/ethinyl estradiol
• immunosuppressants such as cyclosporine (Neoral^®), sirolimus (Rapamune^®) and tacrolimus (Prograf^®)
• phosphodiesterase -5 inhibitors (for erectile dysfunction) such as sildenafil (Viagra^®), tadalafil (Cialis^®, Adcirca^®) and vardenafil (Levitra^®)
• proton pump inhibitors (acid reducers) such as omeprazole

*Not available in Canada

How to take Tybost:

Together with your doctor, you need to decide whether Tybost is right for you.

Stay under a doctor’s care when taking Tybost. Do not change your treatment or stop treatment without first talking with your doctor.

Take Tybost every day exactly as your doctor prescribed it. Follow the directions from your doctor, exactly as written on the label. Set up a dosing schedule and follow it carefully.

When your Tybost supply starts to run low, get more from your doctor or pharmacy. This is very important because the amount of virus in your blood may increase if the medicine is stopped for even a short time. If Tybost is not taken regularly, as prescribed, the virus may become harder to treat.

Only take medicine that has been prescribed specifically for you. Do not give Tybost to others or take medicine prescribed for someone else. Do not use if seal over bottle opening is broken or missing.

Usual dose:

The usual dose of Tybost is one tablet orally (by mouth) once a day. Swallow with plenty of water.

Take Tybost at the same time as atazanavir (Reyataz) with food. Taking Tybost with food helps get the right amount of medicine in your body.

Overdose:

Missed Dose:

It is important that you do not miss any doses.

If you miss a dose of Tybost by less than 12 hours, take the missed dose right away. Then take your next dose as usual with atazanavir (Reyataz). If you miss a dose of Tybost by more than 12 hours, wait and take the next dose of Tybost with atazanavir at your usual time.

If you miss a dose of atazanavir, follow the advice given in the Consumer Information Leaflet for this medicine. If you miss a dose of Tybost and atazanavir, follow the advice given in the Consumer Information Leaflet for atazanavir and take Tybost at the same time as atazanavir.

Do not take 2 doses at the same time. Call your doctor or pharmacist if you are not sure what to do. Always take Tybost with food.

What are possible side effects from using Tybost?

These are not all the possible side effects you may have when taking Tybost. If you experience any side effects not listed here, tell your healthcare professional.

The most common side effect seen in studies which included Tybost is yellowing of the skin, nausea and rash. Other side effects include yellowing of the eyes and an increase in the level of bilirubin in the blood (hyperbilirubinemia).

Changes in your immune system (Immune Reconstitution Inflammatory Syndrome) can happen when you start taking HIV medicines. Your immune system may get stronger and begin to fight infections that have been hidden in your body for a long time, or you could develop an autoimmune disease in which your immune system reacts against your own body (eg, Graves’ disease [which affects the thyroid gland], Guillain-Barré syndrome [which affects the nervous system] or polymyositis [which affects the muscles] and it may develop at any time, sometimes months later after the start of HIV therapy). Sometimes symptoms can be severe, so if you develop high temperature (fever), joint or muscle pain, redness, rash, swelling or fatigue, or any new symptoms, contact your doctor right away.

For more information on the side effects of atazanavir (Reyataz), see the Consumer Information Leaflet for atazanavir.

If you have a troublesome symptom or side effect that is not listed here or becomes bad enough to interfere with your daily activities, tell your healthcare professional.

Reporting Side Effects

Storage:

• Keep Tybost and all other medications out of reach and sight of children.
• Tybost should be stored at room temperature, 15 to 30ºC (59-86ºF). It should remain stable until the expiration date printed on the label.
• Do not keep your medicine in places that are too hot or cold.
• Do not keep medicine that is out of date or that you no longer need. If you throw any medicines away make sure that children will not find them.
• Keep Tybost in its original container and keep the container tightly closed.

If you want more information about Tybost:

• Talk to your healthcare professional.
• Find the full product monograph that is prepared for healthcare professionals and includes this Patient Medication Information by visiting the Health Canada website: (https://www.canada.ca/en/health-canada/services/drugs-health-products/drug-products/drug-product-database.html; the manufacturer’s website (www.gilead.ca), or by calling 1-800-207-4267.

Last Revised August 17, 2021

Gilead Sciences, Inc.

Foster City, CA 94404

USA

Gilead Sciences Canada, Inc.

Mississauga, ON

L5N 2W3

GENVOYA^®, STRIBILD^®, TRUVADA^®, and TYBOST^® are trademarks of Gilead Sciences, Inc. or its related companies.

All other marks referenced herein are the property of their respective owners.

© 2021 Gilead Sciences, Inc. All rights reserved.

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