What is it? Paxlovid is Pfizer’s brand name for an antiviral oral medication (in pill form) that combines two generic drugs, nirmatrelvir and ritonavir. It is fully approved for adults by the Food and Drug Administration (FDA), and has an emergency use authorization (EUA) for adolescents and teenagers, ages 12 and older (and weighing at least 88 pounds). It is meant for people who have a current mild-to-moderate COVID-19 infection and who are at high risk for severe disease. The National Institutes of Health (NIH) prioritizes its use over other treatments for eligible patients.
When it was authorized: December 2021 for adolescents and teenagers ages 12 and older. It was fully approved in May 2023 for adults.
Who can get it: People ages 12 and older who weigh at least 88 pounds, have a positive COVID-19 test result, have mild-to-moderate COVID-19, and are at high risk for developing severe COVID-19.
How you take it: For most people, the dose is three pills twice daily for five days, and it must be started within five days of developing COVID-19 symptoms.
Side effects: The most common side effects of taking Paxlovid include impaired sense of taste (for example, a metallic taste in the mouth) and diarrhea, according to the FDA. Side effects usually are mild, and may include altered or impaired sense of taste, diarrhea, increased blood pressure, or muscle aches. Because Paxlovid is still being studied, it’s possible that all of the risks aren’t yet known.
How it works: Paxlovid is an antiviral medication, a type of drug that stops viruses from replicating inside the body’s cells. Two of the pills in the three-pill dose are nirmatrelvir, which prevents the SARS-CoV-2 virus from replicating. The other medication is ritonavir, which gives the first drug’s levels a boost by essentially shutting down its metabolism in the liver, so that nirmatrelvir levels remain high and can work longer to fight the infection.
How well it works: The FDA’s approval of Paxlovid for adults in 2023 was based on scientific evidence submitted by Pfizer, including efficacy data from a study showing an 86% reduction in risk of COVID-19-related hospitalization or death from any cause in patients. Based on virology data, Paxlovid retains activity against currently circulating Omicron variants, according the latest FDA statement.
In November 2022, the CDC reported on a real-world study that showed adults who took Paxlovid within five days of a COVID-19 diagnosis had a 51% lower hospitalization rate within the next 30 days than those who were not given the drug. The study included people who had been vaccinated or had a previous infection, which the CDC said implied the drug should be offered to people who are eligible regardless of their vaccination status.
What else you should know: Paxlovid interacts with many medications, including common ones that are sold over the counter like St. John’s Wort, blood thinners, cholesterol medicines, and many more. In some cases, this can cause complications that are serious enough to justify not taking it. So, it’s important for health care providers to have an up-to-date medication list, including over-the-counter medications and supplements; they may consider other treatments for some patients. Pharmacists may also provide Paxlovid [with certain limitations], if they’ve opted to do so, provided you can share your electronic or printed medical records, including a list of medications you are already taking, and blood test results from the last 12 months.)
There is no experience treating pregnant women or breastfeeding mothers with Paxlovid. Women who are pregnant should discuss their options with their health care provider. It is also recommended that patients use effective barrier contraception or do not have sexual activity while taking Paxlovid.
Paxlovid is also not recommended for patients with severe liver or kidney disease and those with HIV who are not on treatment.
There have been reports of a “rebound” of COVID-19 symptoms in some people who have completed the five-day course of Paxlovid; in those cases, symptoms have recurred four or five days after completing the treatment. However, when it approved Paxlovid in May, the FDA said there was not a clear association between Paxlovid treatment and a COVID-19 rebound based on available data, and rebound rates in clinical trials were similar among participants who took Paxlovid and those who took a placebo.
CDC guidance for clinicians says a brief return of symptoms may be part of the natural history of SARS-CoV-2 infection in some people, independent of treatment with Paxlovid, adding that there is no evidence additional treatment is needed.
More information: FDA Paxlovid fact sheet for patients, parents, and caregivers.
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