The Food and Drug Administration (FDA) has issued an Emergency Use Authorization (EUA) for molnupiravir, an investigational oral antiviral for the treatment of mild to moderate COVID-19 in adults 18 years of age and older with positive results of direct SARS-CoV-2 viral testing and who are at risk for progressing to severe COVID-19 and/or hospitalization, and for whom alternative COVID-19 treatment options authorized by FDA are not accessible or clinically appropriate.

Molnupiravir is an orally administered form of a ribonucleoside analogue that inhibits the replication of SARS-CoV-2. The EUA was supported by data from the phase 3 MOVe-OUT trial ( Identifier: NCT04575597), which compared the efficacy and safety of molnupiravir to placebo in 775 nonhospitalized adults with symptom onset within 5 days of randomization. Final analysis showed that molnupiravir significantly reduced the risk of hospitalization or death by 30% in at-risk patients with mild to moderate COVID-19. There was 1 death reported in the molnupiravir arm and 9 deaths in the placebo arm.

The most common adverse reactions for molnupiravir (incidence at least 1%) were diarrhea, nausea, and dizziness. Molnupiravir is not recommended for use during pregnancy. Patients should be advised to use effective contraception during treatment and for 4 days after the last dose of molnupiravir. Breastfeeding is not recommended for use during treatment and for 4 days after the last dose of molnupiravir.

The authorized dose for molnupiravir is 800mg (four 200mg capsules) taken orally every 12 hours for 5 days. The treatment should be initiated as soon as a diagnosis of COVID-19 has been made and within 5 days of symptom onset.

Molnupiravir is not authorized for use in patients less than 18 years of age because it may affect bone and cartilage growth, for initiation of treatment in patients hospitalized due to COVID-19, for use for longer than 5 consecutive days, or for pre- or post-exposure prophylaxis for prevention of COVID-19.

Molnupiravir is supplied as 200mg capsules in 40-count bottles. Additional information on the use of molnupiravir can be found in the fact sheet.

“Today’s authorization provides an additional treatment option against the COVID-19 virus in the form of a pill that can be taken orally. Molnupiravir is limited to situations where other FDA-authorized treatments for COVID-19 are inaccessible or are not clinically appropriate and will be a useful treatment option for some patients with COVID-19 at high risk of hospitalization or death,” said Patrizia Cavazzoni, MD, director of the FDA’s Center for Drug Evaluation and Research.


  1. Merck and Ridgeback’s molnupiravir receives US FDA Emergency Use Authorization for the treatment of high-risk adults with mild to moderate COVID-19. News release. Merck and Ridgeback Biotherapeutics. December 23, 2021. Accessed December 27, 2021.
  2. Coronavirus (COVID-19) update: FDA authorizes additional oral antiviral for treatment of COVID-19 in certain adults. News release. US Food and Drug Administration. December 23, 2021. Accessed December 27, 2021.
  3. Molnupiravir fact sheet for health care providers. Accessed December 27, 2021.