How does this medication work? What will it do for me?

This is a combination product that contains 4 medications in 1 tablet: cobicistat, emtricitabine, elvitegravir, and tenofovir alafenamide. These 4 medications are used in combination to treat human immunodeficiency virus (HIV) infection. Together, these medications are antiretroviral medications. This combination product is used to treat HIV-1 infections in adults and adolescents who are 12 years of age or older, weigh more than 35 kg, and have not developed resistance to any of these individual medications for HIV. HIV is the virus responsible for acquired immune deficiency syndrome (AIDS). This product is not intended to be used in combination with any other product.

Emtricitabine and tenofovir belong to the class of medications called nucleoside reverse transcriptase inhibitors (NRTIs). Reverse transcriptase is an enzyme that needed by HIV to multiply and infect other cells. These two medications prevent reverse transcriptase from working properly.

Elvitegravir belongs to the class of medications known as integrase strand transfer inhibitors (INSTIs). Integrase is an enzyme that is needed for the HIV virus to be reproduced. INSTIs stop the action of this enzyme, blocking the virus from reproducing.

Cobicistat slows down the speed at which the body gets rid of these medications. It is included in this medication to increase the length of time that the body is exposed to these medications with each dose.

This medication does not cure AIDS and does not prevent it from being spread to others. It is used in combination with other anti-HIV medications to slow further growth or reproduction of HIV and 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.

What form(s) does this medication come in?

Each green, capsule-shaped, film-coated tablet debossed with "GSI" on one side and the number "510" on the other contains 150 mg of elvitegravir,150 mg of cobicistat, 200 mg of emtricitabine, and 10 mg of tenofovir alafenamide (which is equivalent to 11.2 mg of tenofovir alafenamide hemifumarate). Nonmedicinal ingredients: lactose monohydrate, microcrystalline cellulose, silicon dioxide, croscarmellose sodium, hydroxypropyl cellulose, sodium lauryl sulfate, and magnesium stearate. The tablets are film-coated with a coating material containing indigo carmine (FD&C Blue No. 2) aluminum lake, polyethylene glycol, polyvinyl alcohol, talc, titanium dioxide, and yellow iron oxide.

How should I use this medication?

The recommended dose of this medication is 1 tablet (containing 150 mg of elvitegravir, 150 mg of cobicistat, 200 mg of emtricitabine and 10 mg of tenofovir alafenamide) taken by mouth, once daily.

This medication should be taken with food.

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 it is more than 6 hours until your next dose, take it with food as soon as possible and continue with your regular schedule. If it is less than 6 hours until your next dose, skip the missed dose and continue with your regular dosing schedule.  Do not take more than one dose of this medication in a day. 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 in its original container at room temperature. Protect it from light and moisture, and keep it out of the reach of children.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

Do not take emtricitabine - elvitegravir - cobicistat - tenofovir alafenamide if you:

  • are allergic to cobicistat, emtricitabine, elvitegravir, tenofovir  alafenamide, or any ingredients of the medication
  • are taking any of the following medications:
    • alfuzosin
    • ergot derivatives for migraines (e.g., dihydroergotamine, ergonovine, ergotamine, methylergonovine)
    • cisapride
    • midazolam
    • pimozide
    • rifampin
    • salmeterol
    • seizure medications (e.g., carbamazepine, phenobarbital, or phenytoin)
    • sildenafil for pulmonary arterial hypertension
    • "statin" cholesterol-lowering medications (e.g., atorvastatin, simvastatin, lovastatin)
    • St. John's wort
    • 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.

  • abnormal dreams
  • diarrhea
  • gas
  • headache
  • nausea
  • stomach pain
  • tiredness
  • upset stomach
  • 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)
  • muscle inflammation (e.g., fever, joint or muscle pain, redness, rash, swelling, fatigue)
  • rash
  • signs of infection (symptoms may include fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
  • signs of liver problems (e.g., yellowing of skin and eyes, dark urine, light-coloured stools, nausea, vomiting, and stomach pains)

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

  • signs of lactic acidosis (e.g., nausea, vomiting, increased breathing rate, abdominal pain, unusual tiredness, dizziness, rapid irregular heart rate)
  • signs of pancreatitis (e.g., abdominal pain on the upper left side, back pain, nausea, fever, chills, rapid heartbeat, swollen abdomen)
  • signs of a serious allergic reaction (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)
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.

Bone effects: Tenofovir alafenamide may reduce bone strength and bone growth in adolescents. The effect of tenofovir alafenamide on bone density and risk of fractures is not known, but other forms of tenofovir appear to be associated with decreased bone density. If you experience bone pain or a bone fracture while taking this medication, contact your doctor. Your doctor may do tests to monitor the effect of this medication on your bones. If you have concerns regarding bone health, discuss this with your doctor.

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, breast, around the back, chest, and stomach area, or loss of fat from the legs, arms, and face. The long-term effects of this are not known.

Hepatitis B: For patients with hepatitis B, your doctor will talk to you about HIV treatment before you begin taking this medication. The safety and effectiveness of taking this medication if you have both HIV and hepatitis B have not been determined. People with hepatitis B who have taken emtricitabine or tenofovir (two of the medications in this product) have experienced severe recurrences of hepatitis B when the emtricitabine or tenofovir have been stopped.

Immune reconstitution syndrome: This medication may cause immune reconstitution syndrome, where signs and symptoms of inflammation from previous infections appear. These symptoms occur soon after starting anti-HIV medication 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.

Kidney function: This medication has been reported to cause changes in kidney function. If you have reduced kidney function or kidney disease, 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.

Lactic acidosis and enlarged liver: This medication can cause a rare but serious condition called lactic acidosis (buildup of lactic acid), together with an enlarged fatty liver. Your doctor will periodically monitor you and perform laboratory tests to check your liver function. If you notice any symptoms of this condition such as nausea, vomiting, stomach pain, weakness, tiredness, feeling cold, dizziness, lightheadedness, or irregular heartbeat, seek immediate medical attention.

Liver function: Elvitegravir and cobicistat are removed from the body by the liver and may cause liver problems. If you have liver disease or decreased liver function, 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.

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 (inflammation of the pancreas): Tenofovir may cause or worsen 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. If you develop signs of pancreatitis (e.g., upper left abdominal pain, back pain, nausea, fever, chills, rapid heartbeat, swollen abdomen), contact your doctor.

Stopping the medication: If you stop taking this medication, your HIV infection could get worse. Some people who also have hepatitis B infection experience a flare-up of the hepatitis B when tenofovir or emtricitabine are discontinued. Take the medication exactly as prescribed by your doctor, and do not stop taking the medication without checking with your doctor first.

Pregnancy: This 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 cobicistat, elvitegravir, or tenofovir alafenamide passes into breast milk. Emtricitabine passes into breast milk and may affect your baby. Women 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 who are less than 12 years of age or weigh less than 35 kg.

What other drugs could interact with this medication?

There may be an interaction between cobicistat-emtricitabine-elvitegravir-tenofovir and any of the following:

  • abiraterone
  • acyclovir
  • adefovir
  • alpha blockers (e.g., alfuzosin, doxazosin, silodosin, tamsulosin)
  • aliskiren
  • alitretinoin
  • almotriptan
  • amiodarone
  • aminoglycoside antibiotics (e.g., amikacin, gentamicin, tobramycin)
  • antacids (e.g., aluminum hydroxide, calcium carbonate, sodium bicarbonate)
  • antipsychotic medications (e.g., haloperidol, quetiapine, risperidone)
  • apixaban
  • aprepitant
  • atazanavir
  • atomoxetine
  • “azole” antifungals (e.g., itraconazole, ketoconazole, voriconazole)
  • benzodiazepines (e.g., clonazepam, diazepam, lorazepam)
  • barbiturates (e.g., pentobarbital, phenobarbital)
  • bicalutamide
  • bisoprolol
  • boceprevir
  • bosentan
  • brentuximab
  • brinzolamide
  • bromocriptine
  • buprenorphine
  • buspirone
  • calcitriol
  • calcium channel blockers (e.g., amlodipine, diltiazem, nifedipine, verapamil)
  • cancer-treating medications (e.g., doxorubicin, etoposide, irinotecan, vincristine)
  • captopril
  • carbamazepine
  • carvedilol
  • celecoxib
  • cetirizine
  • chloroquine
  • cidofovir
  • cilostazol
  • cimetidine
  • cinacalcet
  • ciprofloxacin
  • cisapride
  • colchicine
  • conivaptan
  • inhaled corticosteroids (e.g., budesonide, ciclesonide, fluticasone)
  • oral corticosteroids (e.g., budesonide, dexamethasone, methylprednisolone)
  • cyclosporine
  • cyproterone
  • dabigatran
  • dantrolene
  • dapsone
  • darifenacin
  • defirasirox
  • dextromethorphan
  • didanosine
  • digoxin
  • disopyramide
  • dofetilide
  • domperidone
  • dronedarone
  • eplerenone
  • ergot alkaloids (e.g., dihydroergotamine, ergonovine, ergotamine, methylergonovine)
  • estrogens (e.g., conjugated estrogen, estradiol, ethinyl estradiol)
  • ethosuximide
  • everolimus
  • flecainide
  • flutamide
  • “gliptin” diabetes medications (e.g., linagliptin, saxagliptin, sitagliptin)
  • guanfacine
  • HIV non-nucleoside reverse transcriptase inhibitors (NNRTIs; e.g., delaviridine, efavirenz, etravirine, nevirapine)
  • HIV protease inhibitors (e.g., atazanavir, indinavir, ritonavir, saquinavir)
  • hormonal birth control
  • hydrocortisone
  • ivermectin
  • lamivudine
  • levomilnacipran
  • lidocaine
  • lomitapide
  • loperamide
  • losartan
  • macitentan
  • macrolide antibiotics (e.g., clarithromycin, erythromycin)
  • maraviroc
  • mefloquine
  • mestranol
  • methadone
  • methamphetamine
  • metronidazole
  • metoprolol
  • mifepristone
  • mirtazapine
  • modafinil
  • montelukast
  • naloxegol
  • nateglinide
  • nefazodone
  • nitrates (e.g., isosorbide dinitrate,  isosorbide mononitrate)
  • non-steroidal anti-inflammatory medications (NSAIDs; e.g., diclofenac, ibuprofen, naproxen)
  • norfloxacin
  • ondansetron
  • oxcarbazepine
  • oxybutynin
  • perampanel
  • phenytoin
  • phosphodiesterase-5 inhibitors (sildenafil, tadalafil, vardenafil)
  • pimecrolimus
  • prasugrel
  • praziquantel
  • primaquine
  • primidone
  • procainamide
  • progestins (e.g., dienogest, levonorgestrel, medroxyprogesterone, norethindrone)
  • propafenone
  • propranolol
  • protein kinase inhibitors (e.g., bosutinib, crizotinib, dasatinib, imatinib, nilotinib)
  • proton pump inhibitors (PPIs; e.g., lansoprazole, rabeprazole)
  • prucalopride
  • quinidine
  • quinine
  • ranitidine
  • repaglinide
  • rifabutin
  • rifampin
  • riociguat
  • rivaroxaban
  • romidepsin
  • St. John's wort
  • salmeterol
  • saxagliptin
  • selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, fluoxetine, paroxetine, sertraline)
  • simeprevir
  • sirolimus
  • solifenacin
  • "statin" cholesterol medications (e.g., atorvastatin, simvastatin)
  • tacrolimus
  • telaprevir
  • tetrabenazine
  • tetracycline
  • theophylline
  • ticagrelor
  • tizanidine
  • tocilizumab
  • tolterodine
  • tolvaptan
  • tramadol
  • trazodone
  • tricyclic antidepressants (e.g., amitriptyline, imipramine, nortriptyline, trimipramine)
  • trimethoprim
  • ulipristal
  • valacyclovir
  • valganciclovir
  • venlafaxine
  • warfarin
  • zolpidem
  • zopiclone

If you are taking any of these 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. Medications other than those listed above may interact with this medication. 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.