This medication is a combination of three medications: sofosbuvir, velpatasvir, and voxilaprevir. These medications all belong to the class of medications called antivirals. Together, these medications are used to treat chronic hepatitis C infection, caused by specific genetic variants of hepatitis C virus (HCV), after other medications have not been effective.

Sofosbuvir and velpatasvir work by blocking one of the steps in the reproduction of the virus, helping to stop the duplication of the virus and allowing the body to get rid of the virus. Voxilaprevir blocks the action of protease, an enzyme that is needed by viruses for reproduction.

This medication does not prevent the spread of hepatitis C through sexual contact or blood contamination and it does not prevent you from being reinfected with the hepatitis C virus.

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.

The recommended adult dose of sofosbuvir - velpatasvir - voxilaprevir is 1 tablet taken by mouth once a day for 12 weeks.

This medication should be taken with food. Swallow the tablets whole with some water. Do not crush or chew the tablet.

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.

Finish all this medication, even if you have started to feel better. Do not stop taking the medication without talking to your doctor first.

If you vomit and it is less than 4 hours after you have taken the medication, take another dose and continue with your regular schedule. If it is more than 4 hours after you have taken the day's dose of medication, you do not need to take another tablet and can continue with your normal dosing schedule.

If you miss a dose, and it is less than 18 hours since the missed dose, take it 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 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.

Each beige-coloured, capsule-shaped, film-coated tablet debossed with "GSI" on one side and "3" on the other contains 400 mg of sofosbuvir, 100 mg of velpatasvir, and 100 mg of voxilaprevir. Nonmedicinal ingredients: colloidal silicon dioxide, copovidone, croscarmellose sodium, lactose monohydrate, magnesium stearate, and microcrystalline cellulose; film coating: ferrosoferric oxide, iron oxide red, iron oxide yellow, polyethylene glycol, polyvinyl alcohol, talc, and titanium dioxide.

Do not take this medication if you:

• are allergic to sofosbuvir, velpatasvir, voxilaprevir, or any ingredients of the medication
• are taking any of the following medications:
• dabigatran
• phenobarbital
• phenytoin
• rifampin
• rosuvastatin
• St. John's wort

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.

• diarrhea
• decreased energy
• decreased strength
• fatigue
• headache
• nausea
• trouble sleeping
• unusual weakness

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:

• symptoms of slow heartbeat (e.g., fainting or near-fainting, dizziness or lightheadedness, not feeling well; feeling weak or very tired, shortness of breath, chest pains, confusion or memory problems)
• 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)

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

• 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.

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.

Heart rate: Sofosbuvir can cause a life-threatening decrease in heart rate when taken with certain other medications used to regulate the speed that your heart beats. If you are taking medications for heart conditions, particularly heart conditions that affect your heart rate, such as amiodarone, 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.

Hepatitis B reactivation: People who have hepatitis B infection that is dormant may experience the infection returning, causing further liver dysfunction or liver failure. If you have a history of hepatitis B infection, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this mediation, and whether any special monitoring is needed.

If you experience symptoms of worsening liver function, such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.

Human immunodeficiency virus (HIV) co-infection: The safety and effectiveness of using this medication have not been established for people who also have HIV infection. If you have HIV infection, 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. Some of the medications used to treat HIV infection are affected by sofosbuvir, velpatasvir, or voxilaprevir and may contribute to severe side effects.

Liver transplant: The safety and effectiveness of using sofosbuvir - velpatasvir - voxilaprevir while waiting for a liver transplant or after having a liver transplant have not been determined. This medication is not recommended for anyone who has had a liver transplant.

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. This medication is not recommended for people with severe kidney disease or end-stage kidney disease.

Lactose intolerance: This medication is prepared with lactose. If you have lactose or galactose intolerance you should not take this medication.

Liver function: Decreased liver function or liver disease may cause this medication to build up in the body, causing increased 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. This medication is not recommended for people with reduced liver function.

If you experience symptoms of liver problems such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.

Other medications for hepatitis B and hepatitis C: There are several combination medications available to treat viral infections causing hepatitis, and many of these have combinations that include one or more of the ingredients in this medication. They may also include ingredients that work the same way as the ingredients in this medication. Taking 2 combination medications is dangerous and can cause fatal drug interactions. With your doctor or pharmacist, review the ingredients of any medication that may be prescribed and compare it to the medications you are currently taking.

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 sofosbuvir - velpatasvir - voxilaprevir passes into breast milk. If you are breast-feeding and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

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

There may be an interaction between sofosbuvir - velpatasvir - voxilaprevir and any of the following:

• aliskiren
• antacids (e.g., aluminum hydroxide, calcium carbonate, magnesium hydroxide, sodium bicarbonate)
• antiarrhythmics (e.g., amiodarone, dronedarone, propafenone, quinidine)
• "azole" antifungal medications (e.g., fluconazole, ketoconazole, voriconazole)
• bilastine
• bosentan
• calcium channel blockers (e.g., amlodipine, diltiazem, nifedipine, verapamil)
• carvedilol
• cobicistat
• colchicine
• cyclosporine
• dabigatran
• deferasirox
• diabetes medications (e.g., acarbose, canagliflozin, glyburide, liraglutide, lixisenatide, insulin, metformin, rosiglitazone, sitagliptin)
• digoxin
• dipyridamole
• edoxaban
• elagolix
• eltrombopag
• eluxadoline
• enzalutamide
• estrogens (e.g., ethinyl estradiol)
• everolimus
• H2 antagonists (e.g., cimetidine, famotidine)
• other hepatitis C antivirals (e.g., glecaprevir and pibrentasvir, grazoprevir, ledipasvir )
• HIV non-nucleoside reverse transcriptase inhibitors (NNRTIs; e.g., efavirenz, etravirine, nevirapine)
• HIV protease inhibitors (e.g., atazanavir, indinavir, ritonavir, saquinavir)
• leflunomide
• lumacaftor and ivacaftor
• macrolide antibiotics (e.g., azithromycin, clarithromycin, erythromycin)
• medications used to treat cancer (e.g., apalutamide, brentuximab, docetaxel, doxorubicin, etoposide, irinotecan, methotrexate, paclitaxel, venetoclax, vincristine)
• modafinil
• morphine
• nadolol
• naloxegol
• ozanimod
• propranolol
• protein kinase inhibitors (e.g., afatinib, lapatinib, pazopanib)
• proton pump inhibitors (e.g., lansoprazole, omeprazole)
• ranolazine
• rifabutin
• rifampin
• rifaximin
• risperidone
• romidepsin
• St. John's wort
• sarilumab
• seizure medications (e.g., carbamazepine, eslicarbazepine, oxcarbazepine, phenytoin, phenobarbital, primidone)
• silodosin
• siltuximab
• sirolimus
• "statin" anticholesterol medications (e.g., atorvastatin, lovastatin, rosuvastatin, simvastatin)
• sulfasalazine
• tacrolimus
• tenofovir
• teriflunomide
• tocilizumab
• tolvaptan
• warfarin

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.