Ribavirin

Pronunciation: RYE-ba-VYE-rin.

Generic name
ribavirin
Drug class
Nucleoside analogue antiviral (synthetic guanosine analogue)
Form
Capsule, tablet, or oral solution -- 200 mg, 400 mg, or 600 mg strengths depending on brand and market
Route
Oral
Legal status
Prescription-only medicine, always used in combination with another antiviral medicine

Availability and supply rules vary by country

Trade names by country: United States · United Kingdom · Canada · Australia · New Zealand

Australia: Ibavyr (6) · Full directory

What ribavirin is and how it works

Ribavirin is an oral antiviral medicine used only in combination with another antiviral medicine (an interferon, or a direct-acting antiviral) to treat chronic hepatitis C virus infection. It is never effective, and must never be used, on its own. (1) (3)

Ribavirin carries one of the most serious pregnancy-related warnings of any medicine: it can cause severe birth defects or the death of a developing fetus, and this risk applies whether the patient taking ribavirin is the pregnant person OR the male partner of a pregnant person. Because of this, ribavirin must not be started in anyone who is pregnant, and male patients must not take it if their partner is pregnant. Two effective forms of contraception are required during treatment for both male and female patients (and their partners) -- and, critically, for a real, verified period AFTER treatment ends that differs by country: in the US, Canada, Australia, and New Zealand this follow-up period is 6 months for both sexes; in the UK it is 9 months for female patients and 6 months for male patients. Always check which duration applies to your situation with your prescriber. Ribavirin also commonly causes hemolytic anemia (a drop in red blood cells), which can worsen existing heart problems and requires regular blood test monitoring.

Mechanism of action: how ribavirin works

Ribavirin is a synthetic guanosine nucleoside analogue with broad-spectrum antiviral activity; its precise mechanism against hepatitis C virus is not fully established but is thought to involve immunomodulatory effects and inhibition of viral RNA-dependent RNA polymerase. It has a long multiple-dose half-life (approximately 12 days) and can persist in non-plasma compartments (e.g. red blood cells) for months, which underlies the extended post-treatment contraception requirement. (1) (3)

What ribavirin is used for

Chronic hepatitis C virus infection (combination therapy only)

Used together with another antiviral medicine (such as peginterferon alfa-2a, peginterferon alfa-2b, or a direct-acting antiviral) to treat chronic hepatitis C virus infection in adults. Ribavirin is never used alone for this purpose -- monotherapy is not effective. (1) (3)

Before taking ribavirin

Do not take / not appropriate for

  • Do not take ribavirin if you are pregnant, or if you are a man whose partner is pregnant -- ribavirin can cause severe birth defects or loss of the pregnancy, and this is a hard contraindication for both sexes. (all countries) (1) (3)
  • Do not take ribavirin if you have a blood disorder such as thalassemia major or sickle-cell anemia (hemoglobinopathy), autoimmune hepatitis, or significant/unstable heart disease. (United States) (1)
  • Do not take ribavirin if you have severe liver impairment (decompensated liver disease). (United States) (1)

Tell your clinician about

  • Whether you are pregnant, could become pregnant, or whether your partner is or could become pregnant.
  • Any history of heart disease, since hemolytic anemia from ribavirin can worsen cardiac problems.
  • Any blood disorders, including thalassemia or sickle-cell disease.
  • Any history of liver disease or autoimmune conditions.
  • What contraception you and your partner plan to use during and after treatment, and for how long -- this differs by country and your clinician will confirm the exact duration that applies to you.
  • All other medicines you take, since ribavirin is always used alongside another antiviral medicine chosen by your treating clinician.
(1) (3)

How to take ribavirin

  • Ribavirin is always taken together with another antiviral medicine prescribed by your clinician -- never take it on its own.
  • Take exactly the dose and schedule your clinician prescribes; the dose depends on your body weight, the hepatitis C genotype being treated, and whether you also have HIV.
  • Never stop, adjust, or restart ribavirin on your own -- always follow your clinician's instructions, especially around blood test results and contraception planning.
(1)

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3) (4) (5) (6) (7)

Missed dose

If you miss a dose, contact your clinician or pharmacist for guidance rather than doubling your next dose -- ribavirin is always taken as part of a combination regimen and your care team will advise on the best way to get back on schedule.

Overdose

Seek urgent medical attention for a suspected overdose or if you have taken more than your prescribed dose. (1)

Side effects

Side effects and their urgency vary; report severe, persistent, or concerning symptoms.

Fatigue and headache (often related to the interferon combination partner as well as ribavirin itself).

What to notice: Fatigue and headache (often related to the interferon combination partner as well as ribavirin itself).

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

Nausea.

What to notice: Nausea.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

Low red blood cell count (anemia) -- see serious warnings below.

What to notice: Low red blood cell count (anemia) -- see serious warnings below.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

Irritability and difficulty concentrating.

What to notice: Irritability and difficulty concentrating.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (3)

Serious warnings

Signs of hemolytic anemia or worsening heart problems — boxed_warning

Symptoms: Unusual tiredness, shortness of breath, chest pain, rapid or irregular heartbeat, dizziness, or fainting.

Action: Contact your clinical team immediately or seek emergency care -- ribavirin commonly causes hemolytic anemia, which can worsen underlying heart disease and has led to fatal and non-fatal heart attacks. Your clinician will check your blood counts before starting and at week 2 and week 4 of treatment (or more often if needed) and will decide whether your dose needs to be adjusted or treatment paused. (1) (3)

Pregnancy, or a partner's pregnancy, during or after treatment — boxed_warning

Symptoms: Not applicable -- this is a planning and prevention warning rather than a symptom to watch for.

Action: Ribavirin causes severe birth defects and can end a pregnancy; it must not be taken by anyone who is pregnant, and male patients must not take it if their partner is pregnant. Two effective forms of contraception are required for both partners during treatment. Contact your clinician immediately if a pregnancy occurs or is suspected during treatment or during the required post-treatment contraception period. This period differs by country -- in the US, Canada, Australia, and New Zealand it is 6 months for both female and male patients after treatment ends; in the UK it is 9 months for female patients and 6 months for male patients. Confirm the exact duration that applies to you with your prescriber. (1) (3)

Signs of a serious allergic reaction — emergency

Symptoms: Swelling of the face, lips, tongue, or throat; difficulty breathing; widespread rash or hives.

Action: Seek emergency medical help immediately. (1)

Interactions

  • Ribavirin is always prescribed alongside another antiviral medicine (an interferon or a direct-acting antiviral) as part of a combination regimen chosen by your clinician; do not add or stop any other medicine without checking with your prescriber first. (1)

Pregnancy, breastfeeding, kidney/liver function, age

Pregnancy

Contraindicated. Ribavirin causes severe, dose-related birth defects and fetal death in every animal species tested, and is contraindicated in pregnant women and in the male partners of pregnant women. A negative pregnancy test is required immediately before starting treatment, and monthly during treatment and for the required post-treatment period (6 months in the US/Canada/Australia/New Zealand for both sexes; 9 months for female patients and 6 months for male patients in the UK). (1) (2) (3) (4) (5) (6) (7)

Breastfeeding

Specific breastfeeding data were not identified in the sources reviewed for this dossier; discuss with your clinician, since ribavirin is always used with a combination partner medicine that may have its own breastfeeding guidance. (1) (2) (3) (4) (5) (6) (7)

Children

Pediatric dosing and safety data were not the focus of the adult-labeled sources reviewed for this dossier; use in children should only be directed by a specialist clinician. (1) (2) (3) (4) (5) (6) (7)

Elderly

No specific dose adjustment identified for older adults in the sources reviewed; general monitoring for anemia and cardiac risk applies as for any patient, with extra caution given age-related cardiac risk. (1) (2) (3) (4) (5) (6) (7)

Hepatic_impairment

Contraindicated in hepatic decompensation (Child-Pugh score greater than 6) per the US label reviewed. (1) (2) (3) (4) (5) (6) (7)

Renal_impairment

Specific dose-adjustment data for renal impairment were not identified in the sources reviewed for this dossier -- discuss with your clinician if this applies to you. (1) (2) (3) (4) (5) (6) (7)

Monitoring

Before starting

  • Pregnancy test (negative result required immediately before starting)
  • Hemoglobin/hematocrit and complete blood count
  • Baseline ECG
  • Liver function and Child-Pugh assessment
  • Contraception plan for both partners

During treatment

  • Hemoglobin or hematocrit checked before treatment and at week 2 and week 4 of therapy, or more often if clinically indicated.
  • Monthly pregnancy testing during treatment and for the required post-treatment period (6 or 9 months, depending on country and sex -- see serious warnings above).
  • Report any symptoms of anemia, cardiac symptoms, or a missed period/suspected pregnancy to your clinical team immediately.
(1) (3)

Storage

Store at room temperature as directed on the product label, protected from moisture, out of reach of children.

Professional information

Clinician-facing context only, sourced from the current US FDA prescribing information and UK EMC SmPC reviewed for this dossier; verify against the current full label before prescribing.

United States

Indication: Chronic hepatitis C, combination therapy with peginterferon alfa-2a or alfa-2b

Dose summary: Genotype 1/4: 1000-1200 mg/day (weight-based) x 48 weeks. Genotype 2/3: 800 mg/day x 24 weeks. HIV co-infection: 800 mg/day x 48 weeks.

Renal context: Not specifically dose-adjusted in the US label reviewed. (1)

United Kingdom

Indication: Chronic hepatitis C, combination therapy

Dose summary: Combination regimen per treating clinician's protocol; contraception counselling for both sexes is an explicit prescribing requirement, with the UK's own asymmetric 9-month (female)/6-month (male) post-treatment duration.

Renal context: Not specifically dose-adjusted in the UK sources reviewed. (3)

Mechanism of action

Hepatic guidance

Contraindicated in hepatic decompensation (Child-Pugh score greater than 6) per the US label reviewed.

Overdose note

Manage with supportive care; no specific antidote identified in the sources reviewed. (1) (3)

Frequently asked questions

Why does ribavirin have such a strict pregnancy warning, and why does it apply to male patients too?

Ribavirin has caused severe birth defects and fetal death in every animal species tested, at doses well below what humans take. Unlike many pregnancy warnings that only concern the person who might become pregnant, ribavirin's warning also applies to male patients: if a male patient's partner becomes pregnant while he is taking ribavirin or during the required post-treatment period, there is a real risk of harm to the pregnancy. This is why both male and female patients (and their partners) must use two effective forms of contraception. (1) (3)

How long do I need to use contraception after stopping ribavirin?

This genuinely differs by country, and preserving the correct duration matters. In the United States, Canada, Australia, and New Zealand, both female and male patients (and their partners) are advised to continue effective contraception for 6 months after treatment ends. In the United Kingdom, the requirement is different for each sex: female patients are advised to continue for 9 months, while male patients (and their female partners) are advised to continue for 6 months. Always confirm the exact duration that applies to you with your own prescriber, since this can depend on the specific product and country. (1) (3) (5) (6) (7)

Can I take ribavirin by itself?

No. Ribavirin monotherapy is not effective for treating hepatitis C and should never be used alone -- this is stated directly in its boxed warning. It is always prescribed together with another antiviral medicine, such as an interferon or a direct-acting antiviral, as part of a combination regimen your clinician selects. (1) (3)

What is the mechanism of action of ribavirin?

Ribavirin is a synthetic guanosine nucleoside analogue with broad-spectrum antiviral activity; its precise mechanism against hepatitis C virus is not fully established but is thought to involve immunomodulatory effects and inhibition of viral RNA-dependent RNA polymerase. It has a long multiple-dose half-life (approximately 12 days) and can persist in non-plasma compartments (e.g. red blood cells) for months, which underlies the extended post-treatment contraception requirement. (1) (3)

What is the generic name of Ribavirin?

The generic name is ribavirin. (1) (3)

What class of drug is ribavirin?

Ribavirin is classed as: Nucleoside analogue antiviral (synthetic guanosine analogue). (1) (3)

References

  1. REBETOL (ribavirin) capsules, oral solution -- full prescribing informationU.S. Food and Drug Administration / DailyMed (NIH), full prescribing information, Merck Sharp & Dohme · United States · accessed 2026-07-31 · source 1
  2. Copegus (Ribavirin) boxed warning summarySecondary regulatory-content aggregator (rxlist.com), quoting the US FDA COPEGUS (ribavirin tablets, Roche) boxed warning · United States · accessed 2026-07-31 · source 2
  3. Ribavirin 200 mg film-coated tablets -- Summary of Product Characteristicselectronic medicines compendium (emc), United Kingdom -- Milpharm Limited · United Kingdom · accessed 2026-07-31 · source 3
  4. Rebetol, INN-ribavirin -- EPAR; Ribavirin Teva Pharma B.V. -- EPAR (generic)European Medicines Agency (EMA) -- centralised EU marketing authorisation, EPAR (Rebetol, originator; Ribavirin Teva, generic) · European Union · accessed 2026-07-31 · source 4
  5. IBAVYR (ribavirin tablets, USP) -- Product MonographHealth Canada product monograph (IBAVYR / MODERIBA, ribavirin tablets) · Canada · accessed 2026-07-31 · source 5
  6. IBAVYR ribavirin 200 mg film-coated tablets (ARTG 243632) -- Australian Product InformationTherapeutic Goods Administration (TGA), Australia -- Australian Product Information, IBAVYR (ribavirin) tablets · Australia · accessed 2026-07-31 · source 6
  7. IBAVYR 200 mg, 400 mg and 600 mg tablets -- New Zealand Data SheetMedsafe (New Zealand Medicines and Medical Devices Safety Authority) -- New Zealand data sheet, IBAVYR · New Zealand · accessed 2026-07-31 · source 7

Brand names by country

Single-ingredient ribavirin names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

United States

  • Ribavirinum500 [hp_C], 1 [hp_M], 12 [hp_C], 6 [hp_C], 100 [hp_C], 1 [hp_Q], 200 [hp_C], 30 [hp_C] · hahnemann laboratories, inc.

United Kingdom

  • Ribavirin (generic) (3)MHRA licensed emc smpc confirmed · 200 mg tablet, 200 mg capsule · Milpharm Limited

Canada

  • IBAVYR
  • MODERIBA
  • VIRAZOLE

Australia

  • Ibavyr (6)TGA ARTG registered 243632 confirmed · 200 mg · Clinect Pty Ltd

New Zealand

  • Ibavyr (7)Medsafe datasheet indexed confirmed pdf fetch failed secondary confirmation used · 200 mg, 400 mg, 600 mg · Medsafe-registered supplier
View brands in additional countries.

European Union

Rebetol (4), Ribavirin Teva (generic) (4)

This page provides general reference information about ribavirin and is not a substitute for advice from the clinician managing your treatment. All decisions about starting, adjusting, or stopping ribavirin, and about contraception planning, should be made with your prescriber.

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