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Paxlovid: What you need to know

If you’re still following media coverage of the COVID-19 pandemic, you’ve probably heard a lot about Paxlovid recently. Though the Food and Drug Administration (FDA) granted emergency use authorization for this COVID-19 treatment in December, its increasing availability along with recent increases in the number of infections caused by the more transmissible Omicron variant have brought it increasing attention.

Illustration of five sets of three pharmaceutical tablets arranged in two rows, each set of three includes one white tablet and two pink tablets

Paxlovid is an oral antiviral treatment that can be taken at home to prevent high-risk COVID-19 patients from becoming sick enough to be hospitalized. Developed by Pfizer, a clinical trial involving more than 2,220 symptomatic, unvaccinated patients with risk factors such as diabetes, obesity, or age found that the drug reduced the risk of hospitalization or death by 89 percent. While clinical trials for Paxlovid took place before Omicron became predominant, laboratory-based studies appear to show that the drug is effective against this highly transmissible variant.                                                 

Who is eligible to get Paxlovid?

To qualify for a Paxlovid prescription, an individual must be 12 years of age or older, weigh at least 88 pounds, have tested positive for COVID-19, be symptomatic, and be at high risk for developing severe COVID-19 illness. Individuals at high risk include people who are 65 and older and individuals of any age with certain underlying conditions, including cancer, diabetes, or obesity. To be effective, treatment must begin within five days of symptom onset, so you are not eligible to take Paxlovid if you have had COVID-19 symptoms for more than five days.

How do I get Paxlovid?

Paxlovid is available at no cost by prescription only. If you have tested positive for COVID-19, are experiencing symptoms, and are at high risk for developing severe COVID-19 illness, you should obtain a prescription as soon as possible. It is important to act quickly, because you must begin taking Paxlovid within five days of your first symptom.

To get a prescription for Paxlovid, you can contact your primary care provider at MIT Medical or elsewhere. Additionally, the Commonwealth of Massachusetts is providing free telehealth consultations to prescribe Paxlovid to eligible individuals who live in the state. If you qualify, they will arrange for pick-up at a local pharmacy or will have the drug shipped to you overnight. The state also maintains an online COVID-19 Therapeutic Locator that can help you find nearby pharmacies that have the drug in stock.

When do I take it?

You need to begin taking Paxlovid within five days of your first COVID-19 symptoms. It’s important to remember that at-home tests may not return a positive result until several days after your first symptoms have appeared. If you suspect COVID-19 and are at high risk for developing severe illness but get a negative result on your first rapid test, keep testing at home or get a PCR test.

If you are prescribed Paxlovid, you’ll take three pills twice daily for five days.

How does Paxlovid work?

Paxlovid consists of two different medications: nirmatrelvir, a drug that disrupts viral replication, and ritonavir, which boosts the effectiveness of nirmatrelvir by slowing the rate at which it is metabolized by the liver.

What are the possible side effects?

The most common side effects include altered or impaired sense of taste, stomach upset, increased blood pressure, and/or muscle aches.

Can I take Paxlovid if I am taking other drugs?

Paxlovid interacts with a number of other medications, including many widely used medications for chronic conditions, so this is something to discuss with your clinician. In some cases, you may be able to stop taking another medication while you are taking Paxlovid, or your provider may be able to adjust the dose of your other medication(s).

I’ve started hearing about people whose COVID-19 symptoms came back after they finished taking Paxlovid. How concerned should I be?

A case study posted to a preprint server at the end of April describes the experience of a 71-year-old vaccinated and boosted male whose symptoms returned, along with a high viral load, a week after he had completed a five-day course of Paxlovid. Similar cases have been described on social media and in medical blogs.

As it turns out, such relapses were seen in Pfizer’s original clinical trial. This wasn’t mentioned in the results researchers reported in the New England Journal of Medicine, but a report the company submitted to the FDA briefly notes “a rebound in SARS-CoV-2 RNA levels around Day 10 or Day 14” for “several subjects,” something that also occurred for some patients in the placebo group.

Researchers are planning studies to determine why this might happen in some cases. Are these the same people who would have had a longer-than-average period of viral shedding with or without Paxlovid? Are there specific risk factors for viral rebound? Should some people be prescribed a longer course of the medication? “It’s important to be aware that relapses can occur,” says Medical Director Cecilia Stuopis, “but they do not appear common and would not make me less likely to prescribe the drug to a patient who could benefit.”

At the same time, it’s important to be aware of the possibility of relapse, however remote, Stuopis says. “Anyone who becomes symptomatic again shortly after finishing a course of Paxlovid should assume that it’s a relapse and that that they are potentially infectious to others,” she says. “It’s worth confirming with a COVID test and contacting your provider to discuss next steps, but most of these rebound infections appear to be relatively mild and clear quickly without further treatment.”

This news story has not been updated since the date shown. Information contained in this story may be outdated. For current information about MIT Medical’s services, please see relevant areas of the MIT Medical website.