Dasabuvir, ombitasvir, paritaprevir, and ritonavir is used alone or in combination with ribavirin (Copegus, Rebetol, Ribasphere) to treat chronic (long-term) hepatitis C infection (swelling of the liver caused by a virus). Dasabuvir is a non-nucleoside NS5B polymerase inhibitor. It works by decreasing the amount of HCV in the body. Ombitasvir is a hepatitis C virus (HCV) NS5A inhibitor. It works by stopping the virus that causes hepatitis C from spreading inside the body. Paritaprevir is a protease inhibitor. It works by decreasing the amount of HCV in the body. Ritonavir is a protease inhibitor. It helps to increase the amount of paritaprevir in the body so that the medication will have a greater effect.

You may already be infected with hepatitis B (a virus that infects the liver and may cause severe liver damage) but not have any symptoms of the disease. In this case, taking the combination of dasabuvir, ombitasvir, paritaprevir, and ritonavir may increase the risk that your infection will become more serious or life-threatening and you will develop symptoms. Tell your doctor if you have or ever had a hepatitis B virus infection. Your doctor will order a blood test to see if you have or ever had a hepatitis B infection. Your doctor will also monitor you for signs of hepatitis B infection during and for several months after your treatment. If necessary, your doctor may give you medication to treat this infection before and during your treatment with the combination of dasabuvir, ombitasvir, paritaprevir, and ritonavir. If you experience any of the following symptoms during or after your treatment, call your doctor immediately: excessive tiredness, yellowing of the skin or eyes, loss of appetite, nausea or vomiting, pale stools, stomach pain, or dark urine.

Keep all appointments with your doctor and the laboratory. Your doctor may order certain tests before, during, and after your treatment to check your body's response to the combination of dasabuvir, ombitasvir, paritaprevir, and ritonavir.

Talk to your doctor about the risk(s) of taking the combination of dasabuvir, ombitasvir, paritaprevir, and ritonavir.

The combination of dasabuvir, ombitasvir, paritaprevir, and ritonavir comes as extended-release (long-acting) tablets to take by mouth. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take dasabuvir, ombitasvir, paritaprevir, and ritonavir at around the same time every day. Do not take more or less of it or take it more often than prescribed by your doctor.

The extended-release tablets come in a package with 28 days of medication. Each daily dose pack contains 3 tablets that each contain a combination of dasabuvir, ombitasvir, paritaprevir, and ritonavir. Take dasabuvir, ombitasvir, paritaprevir, and ritonavir (3 tablets) every morning with food. Follow the instructions on each daily dose pack about how to remove the tablets.

Swallow the extended-release tablets whole; do not split, chew, or crush them.

Continue to take dasabuvir, ombitasvir, paritaprevir, and ritonavir even if you feel well. The length of your treatment (12 to 24 weeks) depends on your condition, how well you respond to the medication, and whether you experience severe side effects. Do not stop taking dasabuvir, ombitasvir, paritaprevir, and ritonavir without talking to your doctor.

Ask your pharmacist or doctor for a copy of the manufacturer's information for the patient.

Before taking dasabuvir, ombitasvir, paritaprevir, and ritonavir,

• tell your doctor and pharmacist if you are allergic to dasabuvir, ombitasvir, paritaprevir, and ritonavir, any other medications, or any of the ingredients in dasabuvir, ombitasvir, paritaprevir, and ritonavir extended-release tablets. If you have had a serious or life-threatening reaction to ritonavir (rash, blistering or peeling of the skin), your doctor will probably tell not to take dasabuvir, ombitasvir, paritaprevir, and ritonavir. Ask your pharmacist or check the Medication Guide for a list of the ingredients.
• tell your doctor if you are taking alfuzosin (Uroxatral); apalutamide (Erleada); atorvastatin (Lipitor, in Caduet); carbamazepine (Carbatrol, Epitol, Equetro, Tegretol); cisapride (Propulsid; no longer available in U.S.); dronedarone (Multaq); efavirenz (Sustiva, in Atripla); ergot-containing medicines such as dihydroergotamine mesylate (D.H.E. 45, Migranal), ergotamine (Ergomar, in Cafergot, in Migergot), and methylergonovine (Methergine); ethinyl estradiol oral contraceptives such as certain ('birth control pills'), patches, hormonal vaginal rings, and other ethinyl estradiol products; everolimus (Afinitor, Zortress); gemfibrozil (Lopid); lomitapide (Juxtapid); lovastatin (Altoprev); lurasidone (Latuda); midazolam (by mouth); phenytoin (Dilantin, Phenytek); phenobarbital; pimozide (Orap); ranolazine (Ranexa); rifampin (Rifadin, Rimactane, in Rifamate, in Rifater); sildenafil (Revatio) for treatment of pulmonary arterial hypertension; simvastatin (Flolipid, Zocor, in Vytorin); sirolimus (Rapamune); St. John's wort; tacrolimus (Astagraf XL, Envarsus XR, Prograf); or triazolam (Halcion). Also, tell your doctor if you are taking colchicine (Colcrys, Mitigare) and have liver or kidney disease. Your doctor will probably tell you not to take dasabuvir, ombitasvir, paritaprevir, and ritonavir if you are taking one or more of these medications.
• tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: acetaminophen and hydrocodone (Anexsia, Zyfrel); alprazolam (Xanax); angiotensin receptor blockers (ARBs) such as candesartan (Atacand, in Atacand HCT), losartan (Cozaar, in Hyzaar), or valsartan (Diovan, in Diovan HCT, in Exforge); anticoagulants ('blood thinners') such as warfarin (Coumadin, Jantoven); buprenorphine and naloxone (Suboxone, Zubsolv); calcium channel blockers such as amlodipine (Norvasc), diltiazem (Cardizem, Dilacor, Tiazac, others), nifedipine (Adalat, Procardia), or verapamil (Calan, Verelan, others); carisoprodol (Soma); cyclobenzaprine (Amrix); cyclosporine (Gengraf, Neoral, Sandimmune); diazepam (Valium); elagolix (Orilissa); encorafenib (Braftovi); fostamatinib (Tavalisse); fluticasone (Flonase, Flovent, in Advair); furosemide (Lasix); ibrutinib (Imbruvica); ivosidenib (Tibsovo); ketoconazole; medications for irregular heartbeat such as amiodarone (Nexterone, Pacerone), bepridil (no longer available in the U.S.), disopyramide (Norpace), flecainide, lidocaine (Xylocaine), mexiletine, propafenone (Rythmol), or quinidine (in Nuedexta); metformin (Glucophage, Riomet, others); omeprazole (Prilosec); pravastatin (Pravachol); quetiapine (Seroquel); rilpivirine (Edurant; in Complera, in Odefsey); ritonavir (Norvir, in Kaletra) used in combination with other HIV protease inhibitors such as atazanavir (Reyataz), darunavir (Prezista), and lopinavir (in Kaletra); rosuvastatin (Crestor); salmeterol (Serevent, in Advair); and voriconazole (Vfend). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• tell your doctor if you have any type of liver disease other than hepatitis C. Your doctor may tell you not to take dasabuvir, ombitasvir, paritaprevir, and ritonavir.
• tell your doctor if you have ever had a liver transplant, diabetes, or human immunodeficiency virus (HIV).
• tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking dasabuvir, ombitasvir, paritaprevir, and ritonavir, call your doctor.
• you should know that dasabuvir, ombitasvir, paritaprevir, and ritonavir may decrease the effectiveness of hormonal contraceptives (birth control pills, patches, rings, implants, injections, and intrauterine devices). Use another form of birth control while you are taking dasabuvir, ombitasvir, paritaprevir, and ritonavir and for 2 weeks after your final dose. Talk to your doctor about types of birth control that will work for you during and after your treatment with dasabuvir, ombitasvir, paritaprevir, and ritonavir.
• remember not to drink alcohol within 4 hours of taking dasabuvir, ombitasvir, paritaprevir, and ritonavir extended-release tablets.

It is important not to miss or skip any doses. Do not take a double dose to make up for a missed one.

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Keep this medication in the carton it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Do not remove the tablets from the daily dose pack provided by the manufacturer until ready to take them.

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

Unless your doctor tells you otherwise, continue your normal diet.

Dasabuvir, ombitasvir, paritaprevir, and ritonavir may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• difficulty falling asleep or staying asleep
• cough
• irritability
• headache
• diarrhea
• muscle spasms

Some side effects can be serious. If you experience any of these symptoms or those listed in the IMPORTANT WARNING section, call your doctor immediately

• rash
• reddening of the skin
• itching
• hives
• fatigue or lack of energy
• weakness
• confusion

Dasabuvir, ombitasvir, paritaprevir, and ritonavir may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

• Viekira XR® (as a combination product containing Dasabuvir, Ombitasvir, Paritaprevir, and Ritonavir)