Viekira is an antiviral medicine containing a combination of dasabuvir, ombitasvir, paritaprevir, and ritonavir. Dasabuvir, ombitasvir, paritaprevir, and ritonavir are antiviral medicines that prevent the hepatitis C virus (HCV) from multiplying in your body.

Viekira is used to treat chronic hepatitis C in adults. It is sometimes given in combination with another antiviral medicine called ribavirin.

Viekira treats specific genotypes of hepatitis C, and only in certain people. Use only the medications prescribed for you. Do not share your medicine with other people.

Viekira is sometimes used in people who also have HIV. This medicine is not a treatment for HIV or AIDS.

If you have ever had hepatitis B, Viekira can cause this condition to come back or get worse. You will need frequent blood tests to check your liver function.

Before you start taking Viekira, you must stop using certain birth control pills or hormone replacement medicines. Ask your doctor about using non-hormonal birth control to prevent pregnancy.

Viekira is usually taken for 12 to 24 weeks. Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Your doctor will perform blood tests to make sure you do not have conditions that would prevent you from safely using this medicine.

Take this medicine with food.

Viekira XR is an extended-release form of this combination medicine to be taken once daily. Viekira XR is supplied as 3 pale yellow tablets that are taken all at once with a daily meal.

The Viekira Pak contains two different types of tablets. The pink tablet contains only ombitasvir, paritaprevir, and ritonavir. The beige tablet contains only dasabuvir.

Take 2 pink tablets plus 1 beige tablet at the same time every morning. Take 1 beige tablet at the same time every evening.

The monthly Viekira XR or Viekira Pak carton contains enough tablets for you to take this medicine for 4 weeks (28 days in a row).

You will need frequent blood tests to check your liver function.

If you have ever had hepatitis B, Viekira can cause this condition to come back or get worse. You will need liver function tests during treatment and for several months after you stop using this medicine.

Use all medications as directed by your doctor. Read all patient information, medication guides, and instruction sheets provided to you. Do not change your doses or medication schedule without your doctor's advice. Every person with chronic hepatitis C should remain under the care of a doctor.

You should not stop using Viekira suddenly. Stopping suddenly could make your hepatitis C harder to treat with antiviral medicine.

Store this medicine at room temperature away from moisture and heat. Do not remove the tablets from a daily dose package until you are ready to take the medicine.

Usual Adult Dose for Chronic Hepatitis C:

Viekira Pak:
-Dasabuvir: 250 mg orally twice a day (morning and evening)
-Ombitasvir/paritaprevir/ritonavir fixed-dose combination tablet: 2 tablets orally once a day (in the morning)

Extended-release tablets (fixed-dose combination): 3 tablets orally once a day

Recommended Regimen and Duration of Therapy:
-Genotype 1a, without cirrhosis: Viekira Pak plus ribavirin OR extended-release tablets plus ribavirin for 12 weeks
-Genotype 1a, with compensated cirrhosis (Child-Pugh A): Viekira Pak plus ribavirin OR extended-release tablets plus ribavirin for 24 weeks
---For some patients based on prior treatment history: May consider Viekira Pak plus ribavirin OR extended-release tablets plus ribavirin for 12 weeks
-Genotype 1b, with or without compensated cirrhosis (Child-Pugh A): Viekira Pak OR extended-release tablets for 12 weeks
-Liver transplant recipients with normal liver function and mild fibrosis (Metavir fibrosis score 2 or lower), regardless of HCV genotype 1 subtype: Viekira Pak plus ribavirin OR extended-release tablets plus ribavirin for 24 weeks

Comments:
-Recommended for therapy-naive or interferon-experienced patients, including those with HCV/HIV-1 coinfection
-The dosing recommendations for genotype 1a should be followed for patients with unknown genotype 1 subtype or with mixed genotype 1 infection.
-The manufacturer product information should be consulted for ribavirin dosing recommendations (if applicable), regarding dosing of concomitant HIV-1 antiviral drugs in HCV/HIV-1-coinfected patients, and regarding use with calcineurin inhibitors in liver transplant recipients.
-The manufacturer product information for ribavirin should be consulted regarding dose adjustments (if applicable).

Uses: For the treatment of chronic HCV infection
-In genotype 1b-infected patients without cirrhosis or with compensated cirrhosis
-In combination with ribavirin: In genotype 1a-infected patients without cirrhosis or with compensated cirrhosis

You should not use Viekira if you are allergic to dasabuvir, ombitasvir, paritaprevir, or ritonavir, or if:

• you have moderate to severe liver disease; or

• you have ever had a severe skin rash after taking ritonavir (Norvir).

If you take Viekira with ribavirin: There may be other reasons you should not take this combination treatment. Tell your doctor about all your medical conditions.

Many drugs can interact and cause dangerous effects. Some drugs should not be used together with dasabuvir, ombitasvir, paritaprevir, and ritonavir. Your doctor may change your treatment plan if you also use:

• alfuzosin;

• apalutamide;

• colchicine;

• dronedarone;

• efavirenz (Atripla, Sustiva, Symfi);

• ranolazine;

• rifampin;

• sildenafil (Revatio), when taken for pulmonary artery hypertension (PAH);

• St. John's wort;

• oral midazolam (Versed), or triazolam;

• anti-psychotic medicine - lurasidone, pimozide;

• birth control pills or patches - Lo Loestrin FE, Norinyl, Ortho Tri-Cyclen Lo, Ortho Evra, and others;

• hormone replacement therapy such as Fem HRT;

• a vaginal ring such as NuvaRing;

• cholesterol-lowering medicine - atorvastatin, gemfibrozil, lomitapide, lovastatin, simvastatin (Zocor, Vytorin, Simcor);

• an immunosuppressant - everolimus, sirolimus, tacrolimus;

• ergot medicine - dihydroergotamine, ergotamine, methylergonovine; or

• seizure medicine - carbamazepine, phenytoin, phenobarbital.

Before you start taking Viekira, you must stop using medicine that contains ethinyl estradiol. This includes certain birth control pills or hormone replacement medicines. Ask your doctor about using non-hormonal birth control (condom, diaphragm with spermicide) to prevent pregnancy while taking Viekira and for 2 weeks after your treatment ends.

To make sure this medicine is safe for you, tell your doctor if you have ever had:

• liver problems other than hepatitis C (such as cirrhosis or hepatitis B);

• HIV (human immunodeficiency virus);

• a liver transplant; or

• if you use a blood thinner (warfarin, Coumadin, Jantoven) and you have routine "INR" or prothrombin time tests.

It is not known whether Viekira will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

Viekira is sometimes used in combination with ribavirin. Ribavirin can cause birth defects or death in an unborn baby.

• If you are a woman, do not use ribavirin if you are pregnant. You may need to have a negative pregnancy test before taking ribavirin and every month during your treatment.

• If you are a man, do not use ribavirin if your sexual partner is pregnant. An unborn baby could be harmed if you have sex with a pregnant woman while you are taking ribavirin.

While taking Viekira with ribavirin, use at least 2 effective forms of birth control to prevent pregnancy, whether you are a man or a woman. Ribavirin use by either parent may cause birth defects.

Keep using 2 forms of birth control for at least 6 months after your last dose of ribavirin. Tell your doctor right away if a pregnancy occurs while either the mother or the father is using ribavirin.

It may not be safe to breastfeed while using this medicine. Ask your doctor about any risk.

If you miss a dose of the pink tablets, take the missed dose with a meal as soon as you remember. If you are more than 12 hours late, skip the missed dose and take your next dose at the usual time with a meal.

If you forget to take the beige tablet, take it with a meal as soon as you remember. If you are more than 6 hours late in taking the beige tablet, skip the missed dose and take your next dose at the usual time with a meal.

Do not take extra medicine to make up a missed dose.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Do not drink alcohol within 4 hours after you take Viekira XR.

Using Viekira will not prevent your disease from spreading. Do not have unprotected sex or share razors or toothbrushes. Talk with your doctor about safe ways to prevent HCV transmission during sex. Sharing drug or medicine needles is never safe, even for a healthy person.

Get emergency medical help if you have signs of an allergic reaction to Viekira: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have new or worsening symptoms such as:

• confusion;

• loss of appetite, upper stomach pain;

• dark urine, clay-colored stools; or

• jaundice (yellowing of the skin or eyes).

Common Viekira side effects may include:

• nausea;

• itching, skin rash or redness;

• sleep problems (insomnia); or

• feeling weak or tired.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

When you start or stop taking Viekira, your doctor may need to adjust the doses of any other medicines you take on a regular basis.

Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective.

Many drugs can interact with Viekira, and some drugs should not be used together. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide. Tell your doctor about all your current medicines and any medicine you start or stop using.