Key takeaways:
In December 2021, molnupiravir was authorized by the FDA for the treatment of mild to moderate COVID-19 in adults at high risk of severe illness.
Molnupiravir is an oral antiviral pill. If prescribed, you would take 4 capsules by mouth every 12 hours for 5 days.
Molnupiravir has been well-tolerated in studies, with diarrhea being the most common side effect. However, molnupiravir shouldn’t be taken if you’re pregnant, as it may be harmful for unborn babies.
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After three years, the world is still fighting to get a hold on COVID-19. During this time, many advances have been made in treating and preventing this illness. Nonetheless, the pandemic still rages on, with the virus having infected millions and claiming over 1 million lives in the U.S.
So when the pharmaceutical company Merck announced that an antiviral pill may be effective for treating COVID-19, people were understandably excited. This medication is called molnupiravir (Lagevrio). And it’s now authorized by the FDA to treat COVID-19.
Read on below to learn what molnupiravir is, how effective this new medication is, and how to get it should you need it.
What is molnupiravir?
Molnupiravir is an oral antiviral pill. The FDA has granted molnupiravir emergency use authorization (EUA) to treat mild to moderate COVID-19 in adults at high risk of severe illness. High risk people include adults aged 65 and over and people with certain medical conditions. The FDA and National Institutes of Health also state that molnupiravir should only be used when other COVID-19 treatments are unavailable.
Molnupiravir belongs to a group of medications called nucleoside analogs. Molnupiravir treats COVID-19 by stopping the SARS-CoV-2 virus (the virus that causes COVID-19) from making copies of itself. It does this by creating genetic mutations in the virus. These mutations stop the virus from being able to multiply.
Molnupiravir works differently from Pfizer’s COVID-19 pill, Paxlovid (nirmatrelvir/ritonavir). Whereas Paxlovid affects a protein our body makes, molnupiravir affects the virus directly.
How do you take molnupiravir?
A molnupiravir prescription will have 40 capsules in it. Each capsule contains 200 mg of molnupiravir. You’d take 4 capsules (800 mg) by mouth every 12 hours for 5 days.
Molnupiravir should be started within 5 days of first feeling COVID-19 symptoms. This medication can be taken with or without food. It’s very important to finish all the pills prescribed to you even if you start feeling better. This will help molnupiravir to be as effective as possible.
How effective is molnupiravir against COVID-19?
Initially, Merck announced that molnupiravir lowered the number of COVID-19 hospital stays and deaths by about 50% in non-hospitalized adults. But as the phase 3 clinical trial continued, this number changed because more data was collected.
In late November 2021, Merck reported that molnupiravir lowers the risk of COVID-19 hospital stays and deaths by roughly 30%. In the study, less than 7% of those taking molnupiravir were hospitalized or died. In comparison, almost 10% of people taking a placebo (a pill with no medication in it) were hospitalized or died.
Does molnupiravir work against the Omicron variant?
Yes, but there’s concern this may change. A real-world study found that molnupiravir lowers the risk of death with the Omicron variant. However, it doesn’t seem to lower the risk of hospitalization.
Recent research brings to light a different issue, though. As mentioned earlier, molnupiravir works by creating mutations to the COVID virus. Typically, these genetic changes should cause the virus to die. But recent laboratory studies suggest these mutated versions may lead to variants that are resistant to molnupiravir. More research is needed to confirm these findings.
Be sure to check out our regularly updated COVID-19 treatments page. This page includes the most up-to-date information about COVID-19 treatments and their effectiveness.
What side effects does molnupiravir have?
Molnupiravir has been well-tolerated in studies. Merck stated that side effects were similar for study participants taking either molnupiravir or placebo. They also stated that less people taking molnupiravir dropped out of the study due to side effects than those taking placebo.
The most common molnupiravir side effects include:
Diarrhea
Nausea
Dizziness
Based on animal studies, molnupiravir may be harmful for unborn babies. This means pregnant women shouldn’t take molnupiravir. It’s recommended that women who are able to get pregnant use a reliable form of birth control while taking molnupiravir and for 4 days after their last dose.
There’s also concern that molnupiravir could affect sperm. Until further safety studies are done, it’s recommended that males use condoms to prevent pregnancy during and for at least 3 months after finishing molnupiravir treatment.
Molnupiravir can also affect healthy bone development. This is why children and adolescents under 18 years old shouldn’t take this medication. Speak with your child’s healthcare provider about other COVID-19 treatment options.
Does molnupiravir interact with other medications?
Currently, there are no known medication interactions with molnupiravir. It’s important to note that official interaction studies haven’t been completed yet. So this information could change in the future. Discuss the medications and over-the-counter (OTC) supplements you take with your healthcare provider and pharmacist before starting molnupiravir.
How much does molnupiravir cost?
Currently, the U.S. Department of Health and Human Services (HHS) is providing molnupiravir and other COVID-19 treatments at no cost.
In March 2022, the Biden administration launched the Test to Treat initiative. This allows you to get tested for COVID-19 at a participating location. You can also fill a prescription for a COVID-19 treatment, like molnupiravir, at the same location. HHS offers an online locator tool to help you find a Test to Treat clinic or pharmacy. All medications and services provided at Test to Treat locations are free of charge.
How do I get molnupiravir?
As mentioned above, you can get molnupiravir by visiting a Test to Treat location. These all-in-one locations may be the most convenient way for many people to get treatment quickly. You can also get a prescription for your regular healthcare provider, just like for any prescription medication.
It’s important to know that a positive COVID test is no longer needed to qualify for a molnupiravir prescription. A healthcare provider can diagnose you with the condition based on your symptoms, risk factors, and any recent exposures.
Should I get a molnupiravir prescription ahead of time?
No. Stockpiling molnupiravir isn’t recommended at this time. This medication should only be taken if you have mild to moderate COVID symptoms and you’re at high risk for developing severe illness. Molnupiravir should also only be taken if other COVID treatments are unavailable or inappropriate.
The bottom line
In December 2021, the FDA authorized molnupiravir to treat mild to moderate COVID-19 in high-risk adults. Early studies found that this 5-day course of antivirals can lower the risk of death due to COVID-19 by about 30%. Molnupiravir has been well tolerated with few side effects in studies.
Molnupiravir is currently free through the U.S. government. Test to Treat locations can help you get tested for COVID-19 and fill a prescription for treatments, including molnupiravir. Ask your healthcare provider whether molnupiravir is a treatment option if you have COVID-19.
Why trust our experts?
References
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Centers for Disease Control and Prevention. (2022). COVID-19 information for specific groups of people.
Centers for Disease Control and Prevention. (2023). COVID data tracker.
Centers for Disease Control and Prevention. (2023). People with certain medical conditions.
Kabinger, F. (2021). Mechanism of molnupiravir-induced SARS-CoV-2 mutagenesis. Nature Structural & Molecular Biology.
Merck Sharp & Dohme Corp. (2021). Merck and Ridgeback Biotherapeutics provide update on results from MOVe-OUT study of molnupiravir, an investigational oral antiviral medicine, in at risk adults with mild-to-moderate COVID-19.
Merck Sharp & Dohme Corp. (2021). Merck and Ridgeback’s investigational oral antiviral molnupiravir reduced the risk of hospitalization or death by approximately 50 percent compared to placebo for patients with mild or moderate COVID-19 in positive interim analysis of phase 3 study.
Merck Sharp & Dohme Corp. (2021). Merck and Ridgeback’s molnupiravir receives U.S. FDA emergency use authorization for the treatment of high-risk adults with mild to moderate COVID-19.
National Institutes of Health. (2022). Therapeutic management of nonhospitalized adults with COVID-19.
Nature. (2021). How antiviral pill molnupiravir shot ahead in the COVID drug hunt.
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U.S. Food and Drug Administration. (2023). Fact sheet for healthcare providers: emergency use authorization for molnupiravir.
U.S. Food and Drug Administration. (2023). Frequently asked questions on the emergency use authorization for Lagevrio (molnupiravir) for treatment of COVID-19.
U.S. Food and Drug Administration. (2023). Lagevrio Letter of Authorization.
Wong, C. K. H., et al. (2022). Real-world effectiveness of molnupiravir and nirmatrelvir plus ritonavir against mortality, hospitalisation, and in-hospital outcomes among community-dwelling, ambulatory patients with confirmed SARS-CoV-2 infection during the omicron wave in Hong Kong: An observational study. The Lancet.
