The FDA issued an emergency use authorization (EUA) for Pfizer’s oral antiviral nirmatrelvir/ritonavir tablets, co-packaged for oral use (Paxlovid), for the treatment of mild-to-moderate COVID-19 in adults and pediatric patients 12 years of age and older and weighing at least 40 kg (about 88 lb) and with positive results of direct SARS-CoV-2 testing, and who are at high risk for progression to severe COVID-19, including hospitalization or death.
Nirmatrelvir/ritonavir tablets should be initiated as soon as possible after diagnosis of COVID-19 and within 5 days of symptom onset. For patients with normal renal function, Paxlovid is administered as three tablets (two tablets of nirmatrelvir and one tablet of ritonavir) taken together orally twice daily for 5 days, for a total of 30 tablets. Paxlovid is not authorized for use longer than 5 consecutive days.
Paxlovid is not authorized for pre-exposure or postexposure prevention of COVID-19 or for initiation of treatment in those requiring hospitalization due to severe or critical COVID-19. The FDA notes that Paxlovid is not a substitute for vaccination in individuals for whom COVID-19 vaccination and a booster dose are recommended.
The FDA’s EUA for Paxlovid is supported by data from a randomized, double-blind, placebo-controlled clinical trial studying Paxlovid for the treatment of nonhospitalized symptomatic adults with a laboratory-confirmed diagnosis of SARS-CoV-2 infection. Patients were adults 18 years of age or older with a prespecified risk factor for progression to severe disease or were 60 years and older regardless of prespecified chronic health conditions. All patients had not received a COVID-19 vaccine and had not been previously infected with COVID-19. Paxlovid significantly reduced the proportion of people with COVID-19–related hospitalization or death from any cause by 88% compared with placebo among patients treated within 5 days of symptom onset and who did not receive COVID-19 therapeutic monoclonal antibody treatment.
Possible side effects of Paxlovid include impaired sense of taste, diarrhea, hypertension, and muscle aches. Paxlovid is not recommended in patients with severe kidney or liver impairments. In patients with moderate renal impairment, a reduced Paxlovid dose is needed. Using Paxlovid at the same time as certain other drugs may result in potentially significant drug interactions. Consult National Institutes of Health treatment guidelines and the FDA’s Fact Sheet for Healthcare Providers regarding concomitant use of Paxlovid with other medications.
