[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Other antivirals](https://durgical.com/en/pharmacology/classes/other-antivirals/) › Ribavirin

[Pharmacology](https://durgical.com/en/pharmacology/) · [Other antivirals](https://durgical.com/en/pharmacology/classes/other-antivirals/)

# Ribavirin

An old broad-spectrum antiviral, now used with other hepatitis C drugs. It causes haemolytic anaemia and is strongly teratogenic.

Updated 2026-11-01

- Class: [Other antivirals](https://durgical.com/en/pharmacology/classes/other-antivirals/)
- Enzyme: Inosine monophosphate dehydrogenase (IMPDH) and viral RNA polymerase
- ATC code: J05AP01
- WHO Model List of Essential Medicines

✂**Inosine monophosphate dehydrogenase (IMPDH) and viral RNA polymerase**Ribavirin

ⓘ The figure shows ribavirin monophosphate bound to human IMPDH type II, one of its proposed targets.

**Target in 3D:** Inosine monophosphate dehydrogenase (IMPDH) and viral RNA polymerase. PDB structure 1NF7 (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/1NF7) · Drag to rotate · pinch to zoom

## Mechanism of action

Ribavirin is a guanosine analogue phosphorylated by cellular kinases. Its exact mechanism is not fully known; proposed actions include inhibiting IMP dehydrogenase (which depletes GTP), inhibiting the hepatitis C RNA polymerase, increasing viral mutations until the virus can no longer replicate, and shifting T-helper responses. It is not effective alone against hepatitis C.

- Cellular kinases phosphorylate ribavirin
- Ribavirin monophosphate inhibits IMPDH and depletes GTP
- The triphosphate may inhibit viral RNA polymerase and add mutations
- Viral replication falls (only in combination for hepatitis C)

## Pharmacokinetics

**Absorption**
Oral, with food (a fatty meal increases exposure)

**Distribution**
Accumulates in red blood cells and other compartments; may persist for up to 6 months

**Metabolism**
Not a CYP450 substrate or inhibitor

**Elimination**
Slow; clearance falls in kidney disease

**Half-life**
About 12 days with repeated doses

## Indications

- Chronic hepatitis C, always with other drugs (historically with peginterferon alfa) [Viral hepatitis →](https://durgical.com/en/conditions/viral-hepatitis/)
- Added to sofosbuvir-velpatasvir in hepatitis C with decompensated cirrhosis [Cirrhosis →](https://durgical.com/en/conditions/cirrhosis/)

## Adverse effects

### Common

- Fatigue, fever, myalgia and headache
- Nausea, loss of appetite and taste changes
- Insomnia, irritability and depression
- Rash, itching and hair loss

### Serious (rare, important)

- Haemolytic anaemia, which can worsen heart disease and cause myocardial infarction
- Birth defects and fetal death
- Severe depression or suicidal thoughts (with interferon)
- Pancreatitis, lung disorders and severe skin reactions

## Contraindications

- Pregnancy, and men whose female partners are pregnant
- Haemoglobinopathies (thalassaemia major, sickle cell disease)
- Use with didanosine
- Significant or unstable heart disease (because of anaemia)

## Key interactions

**Didanosine**
Contraindicated: fatal liver failure and other toxicities

**Azathioprine**
Severe pancytopenia

**Zidovudine**
More severe anaemia and neutropenia

## What is monitored

- Haemoglobin before treatment and at weeks 2 and 4, then as needed
- Pregnancy test before, monthly during and for 6 months after treatment
- Blood count, liver tests and kidney function
- ECG if there is heart disease

## Administration and safety

- Oral, with food
- Capsules swallowed whole; the oral liquid is shaken before use
- Never used alone for hepatitis C

## Nursing care

- Check haemoglobin results before and early in treatment
- Teach two reliable contraceptive methods for women and for male patients with female partners, during and for 6 months after
- Ask about breathlessness, chest pain, palpitations or marked fatigue
- Screen mood regularly

## Pregnancy and breastfeeding

Contraindicated: it caused birth defects or fetal death in every animal species studied, at exposures far below human ones; pregnancy is avoided for 6 months after the last dose in women and in partners of treated men.

## Memory aid

RIBAvirin «RIps Blood And babies»: haemolytic anaemia and teratogenicity.

## Test yourself

Think of the answer, then tap the question to see it.

## What is the main dose-related toxicity of ribavirin?

Haemolytic anaemia, usually starting in the first 1 to 2 weeks.

## For how long after stopping ribavirin is pregnancy avoided?

Six months, in women and in the female partners of treated men.

## Which human enzyme does ribavirin monophosphate inhibit?

Inosine monophosphate dehydrogenase (IMPDH), depleting GTP.

## Which antiretroviral must never be combined with ribavirin?

Didanosine.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/pharmacology/ribavirin/)

## Related drugs

- [Sofosbuvir + velpatasvir](https://durgical.com/en/pharmacology/sofosbuvir-velpatasvir/)
- [Interferon alfa](https://durgical.com/en/pharmacology/interferon-alfa/)

## Related conditions

- [Viral hepatitis](https://durgical.com/en/conditions/viral-hepatitis/)
- [Cirrhosis](https://durgical.com/en/conditions/cirrhosis/)

[← Back to the class: Other antivirals](https://durgical.com/en/pharmacology/classes/other-antivirals/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - RIBAVIRIN tablet, film coated](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=eee304d0-c2ea-44f4-97d9-92a414d31b6c) (DailyMed (U.S. National Library of Medicine), 2026); [Ribavirin: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a605018.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [DailyMed - SOFOSBUVIR AND VELPATASVIR tablet, film coated](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=d0c1a945-4440-4b5c-81aa-693ed3db597c) (DailyMed (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=J05AP01) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

---
Source: https://durgical.com/en/pharmacology/ribavirin/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/ribavirin/