RibaPak is an antiviral medication that is used to treat chronic hepatitis C.

RibaPak is not effective when used alone. RibaPak must be used in combination with interferon alfa or peginterferon alfa.

RibaPak is sometimes given to people taking other antiviral medications to treat hepatitis C.

RibaPak may also be used for purposes not listed in this medication guide.

You should not use RibaPak if you have autoimmune hepatitis, moderate to severe kidney disease, a hemoglobin blood cell disorder, or if you take didanosine.

RibaPak can harm an unborn baby if the mother or the father is using RibaPak. Do not use if you are pregnant, or if you are a man whose sex partner is pregnant. Both men and women should use effective birth control while taking this medicine and for at least 6 months after the last dose.

RibaPak is not effective when used alone and must be used in combination with an interferon.

In rare cases, RibaPak can cause fatal heart problems. Get emergency medical attention if you have chest pain.

RibaPak is not effective when used alone and must be used in combination with other medications to treat hepatitis C.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Take RibaPak with food.

Swallow the capsule whole and do not crush, chew, break, or open it. Tell your doctor if you have trouble swallowing the capsule.

Measure liquid medicine carefully. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).

Drink extra fluids while you are taking RibaPak to keep from getting dehydrated.

RibaPak can cause dry mouth, which could lead to tooth decay or gum disease. If you vomit while taking this medicine, rinse your mouth out with water to prevent damage to your teeth or gums. Be sure to have regular dental exams while you are taking this medication.

You will need frequent medical tests.

Store RibaPak tablets or capsules at room temperature away from moisture, heat, and light.

Store RibaPak liquid (oral solution) at room temperature or in the refrigerator.

You should not take RibaPak if you are allergic to it, or if you have:

• a hemoglobin blood cell disorder such as sickle-cell anemia or thalassemia;

• autoimmune hepatitis;

• moderate to severe kidney disease;

• if you are also taking didanosine; or

• if you are pregnant, or if you are a man whose sex partner is pregnant.

When you take RibaPak in combination with other medications: There may be other reasons you should not take the combination treatment. Tell your doctor about all your medical conditions.

Tell your doctor if you have ever had:

• a blood cell disorder such as anemia (low red blood cells);

• heart problems, high blood pressure, or heart attack;

• breathing problems;

• vision problems (you may need an eye exam before taking RibaPak);

• diabetes;

• human immunodeficiency virus (HIV or AIDS) or a weak immune system;

• depression, mental illness, thoughts of hurting yourself or others;

• a thyroid disorder;

• kidney disease;

• an organ transplant;

• liver problems other than hepatitis C; or

• treatment for hepatitis C that did not work well.

Both men and women taking RibaPak should use effective birth control to prevent pregnancy. This medicine can cause birth defects, miscarriage, or death to an unborn baby if the mother or father is using this medicine.

• If you are a woman, do not take RibaPak if you are pregnant. You will need to have a negative pregnancy test before taking this medicine. You will also need pregnancy tests during treatment and for 6 months after your last dose.

• If you are a man, do not take RibaPak if your sex partner is pregnant.

• Both men and women should keep using effective birth control for at least 6 months after the last dose of RibaPak.

• Tell your doctor right away if a pregnancy occurs while either the mother or the father is taking RibaPak. Your name may be listed on a pregnancy registry to track the effects of RibaPak on the baby.

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

RibaPak is not approved for use by anyone younger than 3 years old. This medicine tablets are not approved for use by anyone younger than 5 years old.

Take the missed dose on the same day you remember it. Skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Get your prescription refilled before you run out of medicine completely.

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

Avoid drinking alcohol. It can make your liver problems worse.

Using RibaPak will not prevent you from passing hepatitis to other people. Follow your doctor's instructions about how to prevent passing the disease to another person.

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

RibaPak can cause anemia. In rare cases, this can lead to fatal heart problems. Get emergency medical attention if you have chest pain.

RibaPak may cause serious side effects. Call your doctor at once if you have:

• problems with your vision;

• severe pain in your upper stomach spreading to your back, nausea, vomiting, diarrhea;

• new or worsening cough, fever, stabbing chest pain, wheezing, feeling short of breath;

• severe depression, thoughts about suicide, or thoughts about hurting someone else;

• signs of serious anemia--pale or yellowed skin, dark colored urine, confusion or weakness; or

• other signs of low blood cell counts--fever, chills, flu-like symptoms, swollen gums, mouth sores, skin sores, easy bruising, unusual bleeding, feeling light-headed.

RibaPak can affect growth in children. Tell your doctor if your child is not growing at a normal rate while using this medicine.

Common side effects of RibaPak may include:

• nausea, vomiting, loss of appetite;

• fever, chills or shaking;

• low blood cell counts, anemia;

• feeling weak or tired;

• headache, muscle pain; or

• mood changes, feeling anxious or irritable.

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.

Tell your doctor about all your other medicines, especially:

• azathioprine; or

• medicines to treat HIV or AIDS.

This list is not complete. Other drugs may affect RibaPak, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.