[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/) › Molnupiravir # Molnupiravir ## Other antivirals? Other antivirals ## Pregnancy: avoid? Avoid in pregnancy. Not recommended because it may harm the fetus. Contraception is used during treatment and afterwards, by women and by men. An oral COVID-19 antiviral that makes the coronavirus copy its RNA with many errors. It is a reserve option when other treatments cannot be used. Updated Nov 1, 2026 ## Quick facts **Group** [Other antivirals](https://durgical.com/en/pharmacology/classes/other-antivirals/) **Target** SARS-CoV-2 RNA-dependent RNA polymerase (nsp12) **Used for** Mild to moderate COVID-19 **Key effects** Diarrhoea · Nausea · Dizziness **Monitor** Pregnancy test when relevant **ATC** J05AB18 No doses: the clinician sets them by the current guideline. On this page - The basics Mechanism of action - Indications - Adverse effects - Pharmacokinetics - Memory aid - Clinical What the labels mean - Safety Contraindications - Key interactions - What is monitored - Administration and safety - Pregnancy and breastfeeding - Nursing care - Study Test yourself - Connections Connections ## Mechanism of action ✂**SARS-CoV-2 RNA-dependent RNA polymerase (nsp12)**Molnupiravir ⓘ The figure shows the SARS-CoV-2 polymerase with molnupiravir's active form (NHC) built into the template RNA strand, paired with adenine. **Target in 3D:** SARS-CoV-2 RNA-dependent RNA polymerase (nsp12). PDB structure 7OZU (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/7OZU) · Drag to rotate · pinch to zoom Molnupiravir is a prodrug of the nucleoside analogue N4-hydroxycytidine (NHC). Inside cells NHC triphosphate is used by the viral RNA polymerase in place of cytidine or uridine. Once in the RNA, NHC can pair with either guanine or adenine, so later copies collect mutations until the virus can no longer replicate (lethal mutagenesis). - Molnupiravir is converted to NHC triphosphate - The viral polymerase builds NHC into its RNA - NHC pairs with G or A, causing errors - Errors pile up and the virus fails ## Indications - Mild to moderate COVID-19 in adults at high risk of severe disease when other treatments are not available or suitable [COVID-19 →](https://durgical.com/en/conditions/covid-19/) ## Adverse effects ### Common - Diarrhoea - Nausea - Dizziness ### Serious (rare, important) - Possible harm to the fetus (not recommended in pregnancy) - Possible effects on bone and cartilage growth (not used under eighteen years) ## Contraindications - Children and adolescents under eighteen - Hypersensitivity to molnupiravir ## Key interactions **Other medicines** No important interactions are listed; all medicines are still reviewed ## What is monitored - Pregnancy test when relevant - Symptoms of COVID-19 progression ## Administration and safety - Oral capsules swallowed whole, started early after symptoms begin - The full short course is completed ## Pregnancy and breastfeeding Avoid in pregnancy. Not recommended because it may harm the fetus. Contraception is used during treatment and afterwards, by women and by men. ## Nursing care - Check pregnancy status before starting - Teach reliable contraception during and after treatment (women and men) - Advise against breastfeeding during treatment and for a few days after - Teach to seek care if breathing worsens ## Pharmacokinetics **Absorption** Oral capsules, with or without food **Metabolism** Hydrolysed to NHC, which is phosphorylated in cells ## Memory aid MOLNU-pira-VIR: «mole» in the RNA that makes the virus misspell itself to death. ## Test yourself Think of the answer, then tap the question to see it. ## What is the mechanism of molnupiravir? Lethal mutagenesis: its active form NHC is built into viral RNA and causes errors in later copies. ## Why is molnupiravir not recommended in pregnancy? It may harm the fetus. ## Is molnupiravir used in children? No. It may affect bone and cartilage growth and is not used under eighteen years. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/molnupiravir/) [More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology) ## What the labels mean **Pregnancy: avoid** Avoid in pregnancy. Not recommended because it may harm the fetus. Contraception is used during treatment and afterwards, by women and by men. ## Connections ## Related drugs 3 - [Remdesivir](https://durgical.com/en/pharmacology/remdesivir/) - [Nirmatrelvir + ritonavir](https://durgical.com/en/pharmacology/nirmatrelvir-ritonavir/) - [Ribavirin](https://durgical.com/en/pharmacology/ribavirin/) ## Related conditions 1 - [COVID-19](https://durgical.com/en/conditions/covid-19/) [← 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: [Molnupiravir: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a622027.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [SARS-CoV-2 RdRp with Molnupiravir/ NHC in the template strand base-paired with A](https://www.rcsb.org/structure/7OZU) (RCSB Protein Data Bank, 2021); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=J05AB18) (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/molnupiravir/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/molnupiravir/