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Molnupiravir for COVID-19 disease


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.

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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


Available as


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

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.

  • 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

  • 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.

  • 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

  • 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.

  • 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?

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. 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?


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


Drink plenty of water and ask a pharmacist to recommend a suitable painkiller


Do not drive and do not use tools or machines if affected

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

  • Keep 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

Important 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.

Further reading and references

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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