Paxlovid
How Long Does It Take Paxlovid to Work? Plus, 4 More Frequently Asked Questions
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.
Paxlovid seems to be most effective for older adults who aren’t up to date with current COVID vaccine recommendations. But experts still consider it to be valuable in reducing the risk of COVID-related hospitalizations and deaths in high-risk groups.
People typically take Paxlovid 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.
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 this first-choice medication.
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.
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 more recent studies suggest Paxlovid may be less effective than this. Overall, Paxlovid has the greatest benefits for older adults and those who aren’t up to date on their COVID vaccines. The medication may be less effective for younger adults and people who are fully vaccinated.
One study found there was no significant difference in COVID-related hospitalizations or death in vaccinated older adults. But this study was not a randomized controlled trial (the best type of study to show cause and effect). And the researchers didn’t know when participants started Paxlovid, whether they took Paxlovid as prescribed, or how severe their COVID symptoms were. So it makes it hard for researchers to say whether they can apply the study’s findings to a broader population.
A review of multiple studies suggests that Paxlovid can reduce the rate of COVID-related hospitalizations or death by about 40%. Researchers note that the medication had greater benefits for adults ages 65 and older and those who weren’t up to date with their COVID vaccines. But Paxlovid still provided some benefit to younger adults and those who are fully vaccinated.
There are a few reasons why data on Paxlovid’s effectiveness has changed:
Circulating variants: The original studies were conducted with people infected with different COVID variants compared with what’s currently circulating. As the virus that causes COVID mutates over time, the effectiveness of treatments can change.
Vaccination rates: COVID vaccination rates were much lower when the original studies were conducted compared with more recent studies. Vaccines also help lower the risk of COVID-related complications, hospitalizations, and deaths. Paxlovid seems to make a more noticeable difference for a person who has not been vaccinated or isn’t up to date with current vaccine recommendations.
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 you should take.
Interactions with other meds: Paxlovid interacts with hundreds of other medications. But many of these interactions can be managed with dosage adjustments.
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.
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.
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. There are also reports of people taking longer courses to manage long COVID symptoms. In some of these cases, people started Paxlovid several months after they initially recovered from the infection.
These are considered off-label uses of Paxlovid. Prolonged treatment or treatment started more than 5 days after symptoms start isn’t recommended for most people.
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.
There are ways to save on Paxlovid, which is available as a brand-name medication. GoodRx can help you navigate between copay savings cards and patient assistance programs 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 have Medicare or Medicaid or are uninsured, you may be eligible for Paxlovid’s patient assistance program, which offers the medication free of cost.
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 (but this isn’t required).
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 (but this isn’t required).
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 and pharmacist 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 or aren’t up to date with the current vaccine recommendations.
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 has the most benefits for older adults and those who aren’t up to date with the recommended COVID vaccines. But experts still recommend it for people with a higher risk of developing severe illness.
People typically take Paxlovid 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.
Bhatia, A., et al. (2025). Effect of nirmatrelvir/ritonavir (Paxlovid) on hospitalization among adults with COVID-19: An electronic health record-based target trial emulation from N3C. PLoS Medicine.
Centers for Disease Control and Prevention. (2024). Preventing spread of respiratory viruses when you're sick.
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.
Cohen, A. K., et al. (2025). Impact of extended-course oral nirmatrelvir/ritonavir in established Long COVID: A case series. Communications Medicine.
Hammond, J., et al. (2022). Oral nirmatrelvir for high-risk, nonhospitalized adults with COVID-19. The New England Journal of Medicine.
IDSA. (2025). IDSA guidelines on the treatment and management of patients with COVID-19.
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.
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.
Mafi, J. N., et al. (2025). Hospitalizations and mortality among older adults with and without restricted access to nirmatrelvir-ritonavir. JAMA.
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.
Wang, H., et al. (2024). Association of nirmatrelvir–ritonavir with post-acute sequelae and mortality in patients admitted to hospital with COVID-19: A retrospective cohort study. The Lancet Infectious Diseases.
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