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Ribavirin (brands: CoPegus, Rebetol)

Ribavirin is a prescription medication used in combination with other drugs to treat chronic hepatitis C virus (HCV) infection. Ribavirin is a type of drug called a nucleoside analog that works against HCV by interfering with its ability to reproduce itself. Ribavirin is sold under several brand names, including, but not limited to CoPegus, Rebetol, Moderiba and Ribasphere. There are also generic forms of ribavirin available.

What are the ingredients in ribavirin?

Ribavirin is the active ingredient in CoPegus and Rebetol, and each tablet contains 200 mg ribavirin.1,2

How does ribavirin work?

Although the exact way ribavirin works isn’t fully understood, the medication is believed to stop the hepatitis C virus from replicating and spreading inside the body.1,2

What are the possible side effects of ribavirin?

For patients in clinical trials that were treated with ribavirin, side effects included:

  • Redness, soreness, or other reactions at the site of injection (peginterferon, which is taken with ribavirin, is an injected medication)
  • Fatigue or tiredness
  • Headache
  • Fever or chills
  • Nausea
  • Muscle aches
  • Anxiety or emotional irritability1,2

In children that were treated with ribavirin, the most common side effects included:

  • Fever
  • Headache
  • Low white blood cell counts
  • Fatigue or tiredness
  • Loss of appetite
  • Redness at the injection site
  • Vomiting2

Ribavirin may cause a significant reduction in red blood cell count which can cause anemia. Anemia can worsen heart disease and may cause heart attacks which may lead to death. People who have a history of heart disease should not be treated with ribavirin.1,2

Other side effects that may be caused by ribavirin include inflammation of the pancreas (pancreatitis), lung problems, eye problems, dental disorders, and delayed growth in children. These are not all the possible side effects of ribavirin. Patients should talk to their doctor about what to expect with treatment with ribavirin.1,2

Things to know about ribavirin

It is very important for women who are taking ribavirin not to get pregnant. This is because ribavirin can cause serious birth defects, or even death, for an unborn baby. Ribavirin can also be dangerous for a pregnant woman whose male partner is taking ribavirin. During treatment with ribavirin, women are required to use 2 forms of birth control. Extreme care must be taken during treatment and for 6 months after treatment with ribavirin. They will also need to take pregnancy tests before and during treatment with ribavirin.1,2

Before treatment starts, patients should talk to their doctor about all their health conditions, including if they:

  • Have cardiac arrest
  • Have had an organ transplant
  • Have human immunodeficiency virus (HIV)
  • Are pregnant, breastfeeding, or plan to become pregnant or breastfeed1,2

It is not known whether it is safe to breastfeed a child while the mother is taking ribavirin. Women who are breastfeeding or planning to breastfeed should talk to their doctor about the risks.1,2

Some medications can interact badly with ribavirin, or they can make ribavirin work less effectively. Patients should talk to their doctor about all medications they are taking, including prescription and over-the-counter medications, herbal supplements, and vitamins.1,2

Dosing information

The recommended dose of ribavirin is based on the patient’s weight. The dose may be reduced or discontinued if the patient begins experiencing certain side effects or kidney problems.

CoPegus comes in a tablet. CoPegus should be taken with food. Depending on the genotype (strain) of HCV, it is taken for 24 or 48 weeks.1

Rebetol is available in a capsule which is taken by mouth twice daily (morning and night). It should be taken with food. Depending on the genotype (strain) of HCV, it is taken for 24 or 48 weeks.2

For more information on CoPegus, read the full prescribing information.
For more information on Rebetol, read its full prescribing information.

Written by: Emily Downward | Last reviewed: June 2019
  1. CoPegus prescribing information. Genentech. Available at Accessed 2/26/18.
  2. Rebetol prescribing information. Merck. Available at Accessed 2/26/18.