A recent press release issued by U.S FDA on 22 December 2021 stated that oral nirmatrelvir and ritonavir tablets can be used for treating adults and pediatric patients who tested positive for SARS-CoV-2, or those who are at high risk for progression to severe COVID-19 such as hospitalization or death.

This antiviral pill is available by prescription only and it should be initiated within 5 days of symptom onset and as soon as the disease is diagnosed. Nirmatrelvir works by inhibiting the replication of the SARS-CoV-2 virus whereas ritonavir slows down the breakdown of nirmatrelvir so that it can remain for longer periods in the body. This oral antiviral pill is given for 5 days as 3 tablets (2 tablets of nirmatrelvir and 1 tablet of ritonavir) administered twice daily.

The efficacy and safety of this antiviral pill combination have been evaluated in a randomized, double-blind, placebo-controlled clinical trial including non-hospitalized symptomatic adults who had been diagnosed with SARS-CoV-2. The patient who had not received any COVID-19 vaccine and had not previously been infected with COVID-19 were administered with an antiviral pill (n=1,039) and placebo (n=1,046).

The primary endpoints of the study included the percentage of patients who were hospitalized due to COVID-19 progression or died during 28 days of follow up. The findings of the study showed a significant reduction in the percentage of patients with COVID-19 related hospitalization or death. Some possible adverse events such as diarrhea, impaired sense of taste, muscle ache and high blood pressure were also observed in patients who received antiviral pill combination.

The antiviral pill combination was safe and effective for the treatment of COVID-19 but it should not be used for more than 5 days. It is not authorized for pre and post-exposure prevention of COVID-19 and among those who are hospitalized for severe or COVID-19. It cannot act as a substitute for vaccines among individuals who had not received vaccination and booster doses. Also, there is a risk of potential drug interactions and adverse effects in patients with preexisting liver and kidney diseases, so it should be used with caution.