The FDA issued an emergency use authorization (EUA) for Merck’s molnupiravir for the treatment of mild-to-moderate COVID-19 in adults with positive results of direct SARS-CoV-2 viral testing, and who are at high risk for progression to severe COVID-19, including hospitalization or death, and for whom alternative COVID-19 treatment options authorized by the FDA are not accessible or clinically appropriate. Molnupiravir should be initiated as soon as possible after diagnosis of COVID-19 and within 5 days of symptom onset. Molnupiravir is administered as four 200-mg capsules taken orally every 12 hours for 5 days, for a total of 40 capsules. The drug is not authorized for use for longer than 5 consecutive days.
Molnupiravir is not authorized for use in patients younger than 18 years of age because it may affect bone and cartilage growth. It is not authorized for the pre-exposure or postexposure prevention of COVID-19 or for initiation of treatment in patients hospitalized due to COVID-19 because benefit of treatment has not been observed in people when treatment is started after hospitalization due to COVID-19. The FDA notes that molnupiravir is not a substitute for vaccination in individuals for whom COVID-19 vaccination and a booster dose are recommended.
The FDA’s emergency authorization of molnupiravir is based on data from a randomized, double-blind, placebo-controlled clinical trial studying molnupiravir for the treatment of nonhospitalized patients with mild-to-moderate COVID-19 at high risk for progression to severe COVID-19 and/or hospitalization. Patients were adults 18 years of age and older with a prespecified chronic health condition or at increased risk of SARS-CoV-2 infection for other reasons who had not received a COVID-19 vaccine. The study found that of the 709 people who received molnupiravir, 6.8% were hospitalized or died during 29 days of follow-up compared with 9.7% of the 699 people who received placebo. One person who received molnupiravir died during the follow-up period compared with nine people who received placebo.
Side effects observed in the trial included diarrhea, nausea, and dizziness. The safety and effectiveness of molnupiravir for the treatment of COVID-19 continue to be evaluated.
Molnupiravir is not recommended for use during pregnancy because based on animal reproduction studies the drug may cause fetal harm when administered to pregnant individuals. Product labeling contains important information regarding use of reliable birth control for both male and female patients during treatment with molnupiravir as well as how the drug may affect sperm cells.
