Molnupiravir for COVID-19 disease
Lagevrio
Peer reviewed by Sid DajaniLast updated by Michael Stewart, MRPharmSLast updated 15 Dec 2024
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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.
At a glance
Molnupiravir is an antiviral medicine for adults with mild to moderate COVID-19.
It helps stop the COVID-19 virus from spreading quickly in the body.
It is used for people at high risk of severe COVID-19, including those with certain long-term conditions.
Take four capsules every 12 hours for five days, swallowing them whole with water.
Start treatment as soon as possible after symptoms begin or after a positive test.
Common side-effects can include diarrhoea, feeling sick, or dizziness.
In this article:
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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.
Before taking molnupiravir capsules
Back to contentsSome 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.
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.
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How to take molnupiravir capsules
Back to contentsBefore 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.
Swallow the capsules whole with a drink of water. Do not open, crush or chew the capsules.
It is not important whether you take molnupiravir capsules before or after food.
If you forget to take a dose, take it as soon as you remember unless it is nearly time for your next dose. In which case, leave out the forgotten dose and take your next dose when it is due. Do not take two doses together to make up for a missed dose.
Getting the most from your treatment
Back to contentsTreatment 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.
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.
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Can molnupiravir cause problems?
Back to contentsAlong 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. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.
Common molnupiravir side-effects (affecting fewer than 1 in 10 people) | What can I do if I experience this? |
Diarrhoea | Drink plenty of water to replace lost fluids |
Feeling sick (nausea) | Stick to simple foods. Try taking your doses with something to eat if you are not already doing so |
Dizziness | Do not drive and do not use tools or machines if affected |
Important: In rare cases this medicine may cause a serious allergic reaction. Seek urgent medical attention if you develop a red, itchy skin rash and any difficulties with your breathing, including swelling of the face, lips or tongue. Taking an antihistamine may help slow the reaction whilst you are waiting for treatment.
If you experience any other symptoms which you think may be due to this medicine, speak with your doctor or pharmacist.
How to store molnupiravir capsules
Back to contentsKeep all medicines out of the reach and sight of children.
Store in a cool, dry place, away from direct heat and light.
Important information about all medicines
Back to contentsImportant information about all medicines
Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.
This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.
Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.
If you have any questions about this medicine ask your pharmacist.
Report side effects to a medicine or vaccine
If you experience side effects, you can report them online through the Yellow Card website.

Unsure about mixing medicines?
Check for possible interactions between medicines, supplements and foods before taking them together.
Frequently asked questions
What is the age range for taking molnupiravir?
Molnupiravir is specifically used for adults aged 18 and over who have tested positive for COVID-19.
Why is it important to complete the full five-day course of molnupiravir, even if I feel better?
Completing the full course of treatment helps ensure the medication effectively stops the virus from replicating, which can reduce the severity of the infection and lower your risk of being severely ill or requiring hospitalisation. It's crucial to finish the entire course to give the medicine the best chance to work, even if your symptoms improve.
What should I do if I accidentally take two doses of molnupiravir at once?
You should never take two doses together to make up for a missed dose. If you suspect you or someone else might have taken an overdose of this medicine, you should go to the accident and emergency department of your local hospital immediately. Remember to take the medicine container with you, even if it is empty.
What are the common symptoms of a severe allergic reaction to molnupiravir?
Signs of a serious allergic reaction include a red, itchy skin rash, difficulties with your breathing, and swelling of the face, lips, or tongue. If you experience any of these symptoms, you should seek urgent medical attention.
Does molnupiravir interact with any other medications I might be taking?
Before starting molnupiravir, it's important to inform your doctor about all other medicines you are currently taking. This includes any over-the-counter medicines, as well as herbal and complementary medicines. Your doctor needs this information to ensure molnupiravir is suitable for you and to check for potential interactions.
Further reading and references
- Manufacturer's PIL, Lagevrio® 200 mg hard capsules; Merck Sharp and Dohme (UK) Ltd, The electronic Medicines Compendium. Dated July 2024.
- Medicines Complete BNF 89th Edition; British Medical Association and Royal Pharmaceutical Society of Great Britain, London.
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About the authorView full bio

Michael Stewart, MRPharmS
Medicine Leaflet Review Manager – Contractor, Pharmacist
BPharm (Hons), MRPharmS
Michael is a community pharmacist practicing in the Midlands and South Yorkshire with more than 20 years’ experience advising on medicines and medical conditions. He has a strong background in healthcare training, having produced and delivered training courses for pharmacy teams and staff of residential care settings, including nurses. He has also contributed to pharmacy advisory boards for the management of low acuity conditions in the community.
About the reviewer

Sid Dajani
Sultan Dajani qualified at the London School of Pharmacy in 1994 and became the youngest elected member of the Royal Pharmaceutical Society council since its founding in 1842.
Article history
The information on this page is written and peer reviewed by qualified clinicians.
Next review due: 15 Dec 2027
15 Dec 2024 | Latest version

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