New COVID treatments

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Recently the FDA granted emergency use authorization for two oral antiviral medications to treat COVID-19. This is a huge step forward in the fight against the virus since these medications can be taken at home. This will help ease the strain on hospitals, many of which are overcrowded with COVID patients as we enter the second winter of the pandemic.

The first authorization was for a drug called Paxlovid, made by Pfizer. Paxlovid is a combination of two antivirals; nirmatrelvir and ritonavir. Nirmatrelvir inhibits a protease called Mpro, preventing viral replication. Ritonavir is taken with nirmatrelvir to slow its metabolism, making it more effective. The two medications must be taken together in order to be effective. Paxlovid is taken for 5 days, and should be started within 5 days of symptom onset. It is authorized for emergency use in patients 12 years of age or older, who have tested positive for COVID and are at high risk of developing severe COVID.

The second authorization was for a Merck drug called molnupiravir (Lagevrio). It can be used in patients 18 years and older who have tested positive for COVID and are at high risk of progression to severe COVID. Molnupiravir works by forming a compound called NHC which disrupts the viral genome and stops it from multiplying. Molnupiravir is also taken for 5 days, and should be started within 5 days of symptom onset. Recent studies have shown molnupiravir to be less effective than the initial clinical trials, but the drug may have different levels of efficacy for different viral variants. More info here Merck’s COVID pill loses its lustre: what that means for the pandemic (

Remdesivir is another antiviral also in use for COVID treatment, but it is given as an intravenous infusion in the hospital.

Other medications currently being studied for treatment of COVID include nitazoxanide, interferons, stem cells, colchicine, fluvoxamine, ivermectin, and corticosteroids.

For more information see COVID-19 Treatment Guidelines (

PAXLOVID™ (nirmatrelvir tablets; ritonavir tablets) For Patients (

Molnupiravir dosing, indications, interactions, adverse effects, and more (

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