How Long Does It Take Paxlovid to Work? Plus, 4 More Frequently Asked Questions
Key takeaways:
Paxlovid (nirmatrelvir / ritonavir) is a first-choice COVID-19 treatment. Paxlovid generally takes about 1 to 2 days to start relieving symptoms and around 2 to 4 days to fully resolve them.
Original clinical trials found Paxlovid to be about 89% effective against hospitalization and death due to COVID. In a later study, this number lowered to about 37%. But the medication was still 84% effective at preventing COVID-related death.
Paxlovid is typically taken for 5 days. After your last dose, the medication should be fully out of your system within about a day.
There are ways to save on Paxlovid. If you’re eligible, a manufacturer savings card could help you get Paxlovid for as little as $0. There is also a patient assistance program.
Access savings on related medications
Table of contents
If you’re sick with COVID-19, you’re probably looking for something that’ll help you feel better — and fast. Depending on your age and if you have any health conditions, Paxlovid (nirmatrelvir / ritonavir) may be an option.
Here, we’ll answer five frequently asked questions about this prescription-only COVID treatment, including how long Paxlovid takes to work, so you can learn more about the first-choice medication.
1. How long does it take Paxlovid to work?
Paxlovid starts working against the virus that causes COVID after your first dose. Some people notice symptom improvement within 1 to 2 days after starting treatment with Paxlovid. But it may take a few more days for symptoms to fully resolve.
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A study in Korea looked at how fast people taking Paxlovid experienced symptom relief. People with mild-to-moderate COVID reported that their symptoms fully resolved within about 2 to 4 days after starting Paxlovid.
Keep in mind that it’s possible to have lingering symptoms, such as headaches or fatigue, for weeks to months after first getting sick with COVID. But Paxlovid may help lower the risk of developing long-lasting symptoms and long COVID.
After taking Paxlovid, you may feel better several days before you receive a negative COVID test result. One study found that people who took Paxlovid as directed tested negative an average of 10 days after developing symptoms. This was shorter than the time frame for people who didn’t receive any kind of COVID treatment: an average of 17 days.
Note: You should start taking Paxlovid within 5 days of when your symptoms begin. Starting treatment after this point may not provide the same results. Though, your healthcare team may still determine that it's worth prescribing you Paxlovid if you’ve been experiencing symptoms for more than 5 days.
2. How effective is Paxlovid?
In short, Paxlovid is an effective COVID treatment for people with mild-to-moderate symptoms who have a high risk of developing severe illness. It can significantly lower your chances of death due to COVID. And it’s recommended as a first-choice treatment by experts.
When it was first authorized by the FDA, Paxlovid was found to be up to 89% effective against hospitalization and death due to COVID.
But a September 2023 study found Paxlovid to be less effective at preventing hospitalization than first thought. Researchers found that Paxlovid was only about 37% effective against both hospitalization and death. However, when it came to just the prevention of death, it was about 84% effective. We’ll discuss possible reasons for the change in effectiveness below.
Despite these updated numbers, health experts still consider Paxlovid a worthwhile treatment if you have a high risk of developing severe COVID.
Why did Paxlovid’s effectiveness change?
There are a few reasons why data on Paxlovid’s effectiveness has changed. For one, there were different COVID variants circulating when the studies were conducted. As the COVID virus mutates over time, the effectiveness of treatments can change.
Paxlovid’s original clinical trials were conducted before the omicron variant became the strain that infected most people. The 2023 study involved people who were sick with an omicron variant. The variants that are currently circulating are different from what was researched in either study.
Another reason for the change in effectiveness could be the number of people in the study who were vaccinated against COVID or who had previously been infected. During Paxlovid’s initial clinical trials, many people hadn’t been vaccinated. When the 2023 study took place, vaccination rates were much higher.
What it feels like to take Paxlovid: Three people share their experiences with Paxlovid, which can be beneficial for many people at high risk from COVID-19.
Finding the right dosage: Paxlovid has a standard recommended dosage, but drug interactions and other factors, like kidney function, can affect how much a person should take.
Breakthrough treatment: Paxlovid was one of 2023’s most influential new medications. Find out what made it such a game-changer.
In addition to preventing transmission, COVID vaccines also help prevent hospitalization and death due to the illness. People who are vaccinated have a lower risk of complications than people who aren’t. Paxlovid seems to make a more noticeable difference for a person who has not been vaccinated or previously infected.
3. How long does Paxlovid stay in your system?
Paxlovid starts to leave the body pretty quickly. Within about a day after your last dose, the medication should be mostly out of your system. So if you’re having bothersome side effects from Paxlovid, don’t worry. They should start resolving soon after your last dose.
4. How long do you have to take Paxlovid?
The typical Paxlovid dosage is 3 pills (2 nirmatrelvir pills and 1 ritonavir pill) by mouth twice a day for 5 days. If you have kidney problems or take certain medications that can interact with Paxlovid, your daily dose may be lower. But you’d still take the lower dose for 5 days.
Should you take Paxlovid for more than 5 days?
It’s not typically recommended to take Paxlovid for more than 5 days.
There is a completed clinical trial that looked into whether taking another 5 days of Paxlovid would be helpful for people who experience rebound (returning) COVID symptoms. The results of this study haven’t been published yet.
There have been reports of people taking Paxlovid for more than the standard 5 days. Most of these reports have involved people who have weakened immune systems due to cancer. This is considered an off-label use of Paxlovid, however. Prolonged treatment isn’t recommended for most people.
Test your knowledge about Paxlovid
5. Is Paxlovid safe to take?
Yes, Paxlovid is considered safe for most people to take. The medication’s side effects are generally mild and resolve quickly.
Common Paxlovid side effects include:
Temporary changes in taste (“Paxlovid mouth”)
Diarrhea
Temporary increase in blood pressure
Headaches
The ritonavir component of Paxlovid is known to cause liver damage. However, this has not been reported by people taking Paxlovid. To be safe, it’s not recommended to take this COVID treatment if you have severe liver disease.
Additionally, several medications interact with Paxlovid. Some of these interactions could cause serious complications. In some cases, it’s recommended to avoid combining the medications completely. So be sure to share a list of your medications, including over-the-counter and herbal products, with your healthcare team before taking Paxlovid. This will help them look for and manage potential interactions.
How to save on Paxlovid
There are ways to save on Paxlovid, which is available as a brand-name medication. GoodRx can help you navigate between patient assistance programs and copay savings cards to save money on your prescription:
Save with a copay savings card. If you have commercial insurance, you may be eligible to pay as little as $0 for Paxlovid using a savings card from the manufacturer.
Save with a patient assistance program. If you’re uninsured or underinsured, you may be eligible for Paxlovid’s patient assistance program, which offers the medication free of cost.
Frequently asked questions
In general, you’re most likely contagious for about 5 days after taking Paxlovid. But some people may be contagious longer than this.
You’re most contagious during the first 3 days after developing COVID symptoms or testing positive for it. If you have mild symptoms, the CDC recommends staying home and away from others until you’re feeling better overall and have been fever-free (without fever reducers) for at least 24 hours. After this, it’s still recommended to stay home or distance yourself from others if you can for the next 5 days. You may also consider taking a COVID test during this time to see if you’re testing negative.
Paxlovid interacts with hundreds of medications. Some common examples include statin cholesterol medications, blood thinners, and triptan migraine medications. Some of these interactions can lead to serious side effects. You’ll need to share an updated list of medications with your prescriber in order to receive Paxlovid. Be sure to include all over-the-counter medications and supplements on your list.
Paxlovid can cause side effects for some people. These side effects are generally mild and usually go away shortly after the last dose. But they can be uncomfortable while they’re happening. The most common Paxlovid side effect is a bitter or metallic taste in the mouth. Some people find that eating strongly flavored candies or drinking extra fluids helps lessen this side effect.
Yes, Paxlovid really works. But it’s most beneficial for those who have a higher risk of developing severe COVID. Examples of higher risk groups include older adults and people with certain chronic health conditions, such as Type 2 diabetes. Paxlovid also has more noticeable effects for people who have never received a COVID vaccine.
The bottom line
Paxlovid (nirmatrelvir / ritonavir) is a first-choice treatment option for mild-to-moderate COVID-19. Many people notice that Paxlovid starts relieving symptoms in about 1 to 2 days. But it often takes about 2 to 4 days for symptoms to fully resolve.
Studies show that Paxlovid is about 37% effective at preventing hospitalization and death due to COVID. But when looking only at death prevention, it’s about 84% effective.
Paxlovid is typically taken for 5 days. Within about a day after finishing your last dose, the medication should be mostly out of your system. Be sure to discuss any additional Paxlovid questions or concerns with your healthcare team.
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References
Bhimraj, A., et al. (2024). IDSA guidelines on the treatment and management of patients with COVID-19. Clinical Infectious Diseases.
Centers for Disease Control and Prevention. (2024). Respiratory virus guidance update frequently asked questions.
ClinicalTrials.gov. (2024). A study to learn about a repeat 5-day treatment with the study medicines (called nirmatrelvir/ritonavir) in people 12 years old or older with return of COVID-19 symptoms and SARS-CoV-2 positivity after finishing treatment with nirmatrelvir/ritonavir.
Hammond, J., et al. (2022). Oral nirmatrelvir for high-risk, nonhospitalized adults with COVID-19. The New England Journal of Medicine.
Li, H., et al. (2022). Association of nirmatrelvir/ritonavir treatment on upper respiratory severe acute respiratory syndrome coronavirus 2 reverse transcription-polymerase chain reaction (SARS-Cov-2 RT-PCR) negative conversion rates among high-risk patients with coronavirus disease 2019 (COVID-19). Clinical Infectious Diseases.
Lin, D., et al. (2023). Nirmatrelvir or molnupiravir use and severe outcomes from omicron infections. JAMA Network Open.
Liu, C., et al. (2023). Successful treatment of persistent symptomatic coronavirus disease 19 infection with extended-duration nirmatrelvir-ritonavir among outpatients with hematologic cancer. Open Forum Infectious Diseases.
Park, J. J., et al. (2022). Nirmatrelvir/ritonavir prescription rate and outcomes in coronavirus disease 2019: A single center study. Infection and Chemotherapy.
Pfizer Laboratories. (2024). Paxlovid - nirmatrelvir and ritonavir [package insert].
Snell, L. B., et al. (2023). A multinational case series describing successful treatment of persistent severe acute respiratory syndrome coronavirus 2 infection caused by omicron sublineages with prolonged courses of nirmatrelvir/ritonavir. Open Forum Infectious Diseases.
World Health Organization. (2024). Tracking SARS-CoV-2 variants.
Xie, Y., et al. (2023). Association of treatment with nirmatrelvir and the risk of post-COVID-19 condition. JAMA Internal Medicine.
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