Molnupiravir 5-Day Course: What Adults Need To Know
Antiviral treatment to reduce severe COVID-19 risk in high-risk adults when started early after symptoms.
Taking
molnupiravir
as soon as possible once COVID-19 symptoms have started can lower your risk of being severely ill or requiring hospitalisation.Molnupiravir is given to adults aged over 18 years when they have tested positive for COVID-19 and have at least one risk factor for developing severe illness. Treatment should be started as soon as possible after diagnosis and within the first five days of symptoms. The most common side-effects are feeling sick (nausea) and diarrhoea.
About molnupiravir
| Type of medicine | Antiviral agent |
|---|---|
| Used for | Treatment of mild to moderate COVID-19 disease in adults |
| Also called | Lagevrio® |
| Available as | Capsules |
Molnupiravir is an antiviral agent that works by combining with viral RNA to stop the virus particles from replicating. If a virus can’t replicate it won’t be able to infect other cells in the body and the infection won’t spread as quickly. Molnupiravir can reduce the severity of viral infections such as COVID-19.
Molnupiravir is used for adults who have tested positive for COVID-19 and have at least one risk factor for severe disease. Taking molnupiravir as soon as possible once COVID-19 symptoms have started can lower your risk of being severely ill or requiring hospitalisation.
People at high risk of severe COVID-19 disease include those with medical conditions such as long-term heart, lung, liver, kidney or nerve problems, people with diabetes and people with weakened immune systems. Specific groups often eligible include adults aged 65 and older, or those aged 18-64 with conditions like obesity, chronic lung disease, or immunocompromise, regardless of vaccination status in some guidelines.
Before taking molnupiravir capsules
Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking molnupiravir it is important that your doctor knows:
- If you are pregnant, trying for a baby, or breastfeeding. Molnupiravir is not recommended during pregnancy due to potential risks to fetal development; effective contraception is advised during treatment and for 4 weeks after for women of childbearing potential, and for men for 3 months after.
- If you have ever had an allergic reaction to a medicine.
- If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines. No major drug interactions are widely reported, but inform your doctor of all medications.
Additionally, molnupiravir is typically reserved for cases where alternative treatments like nirmatrelvir plus ritonavir (Paxlovid) or remdesivir are not accessible or clinically appropriate.
How to take molnupiravir capsules
Before you start this treatment, read the manufacturer’s printed information leaflet from inside your pack. The manufacturer’s leaflet will give you more information about molnupiravir and a full list of side-effects which you may experience from taking it.
The usual dose of molnupiravir is four capsules (800 mg) taken every twelve hours for five days. Make sure you complete the course even if you are feeling better. It can be taken with or without food.
- Swallow the capsules whole with a drink of water.
- Take doses approximately 12 hours apart (e.g., 8 AM and 8 PM).
- Do not crush or chew the capsules.
A qualified healthcare provider must prescribe this medication, often under emergency use authorization or specific national guidelines.
Getting the most from your treatment
Treatment with molnupiravir should be started within the first five days of COVID-19 symptoms or as soon as possible after a positive COVID-19 test result.
Make sure you complete the full course of treatment even if you start to feel better or do not feel unwell. Completing the course helps prevent the development of treatment-resistant virus strains.
- Help your body fight the infection by drinking plenty of water, eating sensibly and getting plenty of rest.
- The best way to protect yourself from COVID-19 is through vaccination. Ensure your vaccinations are up to date in line with national guidance.
- Follow current government guidance on self-isolation and testing after a positive COVID-19 test.
Possible side-effects
Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with molnupiravir.
| Common side-effects (affect more than 1 in 100 people) | What can I do if I experience this? |
|---|---|
| Feeling sick (nausea), diarrhoea, dizziness | Stick to simple meals (avoid rich or spicy foods). Take small sips of water often. Speak with your doctor if severe or persistent |
Serious side-effects are rare. If you develop any unusual symptoms, contact your doctor promptly. Clinical trials showed molnupiravir reduced hospitalization or death risk by around 30% in high-risk patients, though efficacy can vary.
How to store molnupiravir
Keep all medicines out of the reach and sight of children. Store capsules at room temperature, away from heat, moisture, and direct light. Do not use after the expiry date. Return any unused medicine to your pharmacist.
Frequently Asked Questions (FAQs)
Q: Who is eligible for molnupiravir?
A: Adults 18+ with mild-moderate COVID-19 at high risk for severe disease (e.g., age 65+, chronic conditions, immunocompromised) when started within 5 days of symptoms and alternatives unavailable.
Q: How does molnupiravir work?
A: It introduces errors into the SARS-CoV-2 viral RNA, preventing replication and reducing viral spread.
Q: Can pregnant or breastfeeding individuals take it?
A: No, it is contraindicated due to potential harm to fetus or infant. Use contraception as advised.
Q: What if I miss a dose?
A: Take it as soon as remembered unless near next dose. Do not double up. Complete full 5-day course.
Q: Is molnupiravir a substitute for vaccination?
A: No, vaccination is primary prevention. Molnupiravir treats active infection in high-risk cases.
When not to take molnupiravir
- Not for children under 18, as safety not established.
- Not for severe COVID-19 requiring hospitalization.
- Avoid if alternatives like Paxlovid available.
Clinical Evidence and Updates
Molnupiravir received Emergency Use Authorization in various countries for high-risk patients. Studies like MOVe-OUT trial demonstrated reduced progression to hospitalization. Always consult latest guidelines, as recommendations evolve with variants and new therapies.
References
- Molnupiravir for COVID-19 disease (Lagevrio) — Patient.info. 2023. https://patient.info/medicine/molnupiravir-for-covid-19-disease-lagevrio
- Patient information for Molnupiravir — UK Government. 2023-01-13. https://www.gov.uk/government/publications/covid-19-antiviral-treatment-molnupiravir/patient-information-for-molnupiravir
- Molnupiravir Information for the Public — Michigan.gov. 2023. https://www.michigan.gov/coronavirus/resources/therapeutics-information-page/general-information/antiviral/content/molnupiravir-information-for-the-public
- Treatments for COVID-19 — NHS.uk. 2024. https://www.nhs.uk/conditions/covid-19/treatments-for-covid-19/
- Molnupiravir Patient Fact Sheet — Merck.com (FDA EUA). 2023-12-23. https://www.merck.com/eua/molnupiravir-patient-fact-sheet-english.pdf
- Molnupiravir (oral route) — Mayo Clinic. 2024. https://www.mayoclinic.org/drugs-supplements/molnupiravir-oral-route/description/drg-20524779
- Molnupiravir for treating COVID-19 — NCBI Bookshelf (NIH). 2024. https://www.ncbi.nlm.nih.gov/books/NBK615902
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