Ribavirin belongs to the class of medications called antivirals. It is used in combination with other medications to treat adults with chronic hepatitis C (a disease of the liver). Ribavirin works by helping the immune system fight the hepatitis C virus, and by making it harder for the virus to reproduce within the body.

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 usual dose of ribavirin depends on a person's body weight, disease characteristics, and treatment regimen. Ribavirin is taken in 2 doses (morning and evening) with food. Swallow the tablets whole, and do not crush, break, or chew them.

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, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose (i.e., less than 6 hours before the 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 at room temperature, protect it from light and moisture, and keep it out of the reach of children.

Do not use ribavirin if you:

• are allergic to ribavirin or any ingredients of this medication
• are pregnant or planning to become pregnant
• have a female partner who is pregnant or planning to become pregnant
• have a blood disorder (e.g., thalassemia or sickle-cell anemia)
• are taking the medication didanosine

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.

• difficulty sleeping
• flu-like symptoms (e.g., body aches, sore throat, fever or chills)
• headache
• irritability
• itching
• nausea
• tiredness
• weakness

In addition to the side effects noted above, other common side effects when this medication is taken in combination with both sofosbuvir and peginterferon include low white blood cells and nausea.

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• shortness of breath
• signs of anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
• signs of bleeding (e.g., unusual nosebleeds, bruising, blood in urine, coughing blood, bleeding gums, cuts that don't stop bleeding)
• signs of infection (symptoms may include fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, cough, headache, stiff neck, weight loss, or listlessness)
• vision changes

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

• signs of a serious allergic reaction (e.g., rash; hives; swelling of the face, mouth, lips, throat, and tongue; difficulty swallowing or breathing)
• signs of a severe skin reaction (e.g., blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever or discomfort)
• symptoms of hemolytic anemia (e.g., unusual paleness; yellowish skin, eyes and mouth; dark-coloured urine; fever; dizziness; weakness; increased heart rate)

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.

Anemia: Ribavirin may cause low levels of red blood cells. If you experience symptoms of reduced red blood cell count (anemia) such as shortness of breath, feeling unusually tired, or pale skin, contact your doctor as soon as possible.

Your doctor will do blood tests regularly to monitor the number of specific types of blood cells, including red blood cells, in your blood.

Blood tests: Your doctor may recommend that you have blood tests regularly while you are taking this medication.

Heart problems: If you have heart 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.

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.

Pregnancy: Ribavirin can cause serious birth defects. Do not use this medication if you are pregnant or planning to become pregnant. If you have a female partner, do not use this medication if she is pregnant or planning to become pregnant. While taking this medication and for 6 months after stopping the medication, use two reliable forms of birth control (one for each partner). This applies to women taking ribavirin as well as female partners of men taking ribavirin. Contact your doctor immediately if a pregnancy occurs while you or your partner are taking this medication or within 6 months after the medication is stopped.

Breast-feeding: It is not known if ribavirin passes into breast milk. If you are a breast-feeding mother and are using this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of this medication for children younger than 18 years of age have not been established.

Seniors: Seniors may have a higher risk of side effects from this medication.

There may be an interaction between ribavirin and any of the following:

• azathioprine
• cladribine
• didanosine
• influenza virus vaccine
• interferons
• warfarin
• zidovudine

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.