Health Canada has authorized the combination of two antiviral drugs, nirmatrelvir and ritonavir (brand name PAXLOVID), to treat adults with mild to moderate COVID-19 who are at high risk of progressing to serious disease, including hospitalization or death. The active ingredient nirmatrelvir in PAXLOVID works by stopping the virus from replicating.

Until now, authorized medications for COVID-19 have had to be taken in a hospital or healthcare setting. PAXLOVID is the first COVID-19 therapy that can be taken at home. The drug is intended for use as soon as possible after diagnosis of COVID-19 and within five days of the start of symptoms. The treatment consists of two tablets of nirmatrelvir and one tablet of ritonavir taken together by mouth twice per day for five days.

Health Canada received the submission for PAXLOVID from Pfizer on December 1, 2021, and conducted an expedited review. Pfizer submitted the data to Health Canada on a rolling basis throughout the review process, as new information became available to facilitate a decision as quickly as possible. These data included results from clinical trials for PAXLOVID where patients had not been vaccinated and had not previously been infected with COVID-19.

While the benefits of PAXLOVID were found to outweigh the risks, it can cause interactions with other medications for some patients. As such, patients should discuss the risks and benefits of treatment with their healthcare provider.

As with all COVID-19 health products, Health Canada will continue to monitor the safety and effectiveness of this drug once it is on the market. Pfizer will continue to provide additional data, including data on the potential impacts of existing and new variants of concern. If any new concerns are identified, Health Canada will take immediate action and communicate with Canadians.

No drug, including PAXLOVID, is a substitute for vaccination. Vaccination remains the most important tool in preventing serious illness from COVID-19 infection. Both the Public Health Agency of Canada and Health Canada continue to strongly recommend vaccination for all eligible Canadians, including those who are pregnant, may become pregnant or are breast-feeding.