Molnupiravir, an antiviral drug that can be taken at home, was approved by the UK medicines regulatory authority on 4 November 2021. It is the first oral drug approved for use against COVID-19.
The pill, which bears the brand name Lagevrio, was developed by the pharmaceutical companies Ridgeback Biotherapeutics and Merck, Sharp and Dohme (MSD). The UK has ordered 480,000 courses and the first deliveries are expected to arrive in November.
Health and Social Care Minister Sajid Javid described the drug as a “game-changer”. He said: “This antiviral will be an excellent addition to our arsenal against COVID-19, and it remains vital that everyone comes forward for their life-saving COVID-19 vaccine – especially those who qualify for a booster.” – to insure as many people as possible will be protected in the coming months.”
What is molnupiravir?
The antiviral drug molnupiravir was originally developed to treat the flu. Since it is an oral medication, it can be taken at home while other treatments are taken intravenously or injected by a health care professional.
The drug is administered to patients with mild to moderate COVID-19 within 5 days of the onset of symptoms.
How does molnupiravir work?
Molnupiravir works by interfering with the reproduction of the virus.
As soon as the virus enters the cells of the body, it replicates its genome, which consists not of DNA but of RNA (ribonucleic acid). These replicated genomes are then formed into complete virus particles that burst out of the cell and continue to spread throughout the body.
However, the molecules of molnupiravir are absorbed by virus-infected cells, where they are converted into a defective version of the building blocks of RNA. So when the virus tries to replicate, the resulting virus particles have defective genetic material and can no longer reproduce. This means that the viral load must remain low, which reduces the risk of serious diseases.
Since molnupiravir targets the RNA that uses SARS-CoV-2 as building blocks, it should be equally effective against all variants of the coronavirus.
“This mechanism of action has some limitations and the drug cannot be given to pregnant women because of the risk of harming an unborn baby,” said Prof Penny Ward, visiting professor of Pharmaceutical Medicine at King’s College London.
How effective is molnupiravir?
“During clinical trials, Lagevrio was shown to be effective in reducing the risk of hospitalization or death for non-hospitalized adults with a mild to moderate infection risk by 50 percent,” said Professor Sir Munir Pirmohamed, Chair of the Human Medicines Commission.
In a non-peer-reviewed study, 775 patients who had recently contracted COVID-19 were given either molnupiravir or a placebo. In the molnupiravir group, 7.3 percent were hospitalized and no patients died; 14.1 percent of the placebo group were hospitalized and there were eight deaths.
“After a thorough review of the data by our expert scientists and clinicians, we are pleased that Lagevrio (molnupiravir) is safe and effective for people at risk of developing severe COVID-19 disease and have granted its approval,” said Dr June Raine, Chief Executive of the UK Medicines and Healthcare products Regulatory Agency (MHRA).
However, the pill must be given within five days of the appearance of symptoms; it is not effective if taken after the patient is hospitalized.
Who is molnupiravir prescribed for?
The MHRA has approved the use of molnupiravir in patients with mild to moderate COVID-19 and at least one risk factor, such as obesity, old age, diabetes or heart disease.
The drug can be offered to care homes and prescribed by general practitioners to vulnerable patients.
The treatment will initially be given to both vaccinated and unvaccinated patients in the UK as part of a national study to gather more data on its effectiveness.
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