How long does it take Paxlovid to work?

Paxlovid (nirmatrelvir/ritonavir) is an oral antiviral medication used to treat mild-to-moderate COVID-19 in people at high risk for severe illness. COVID-19 is caused by the SARS-CoV-2 virus.

Worldwide COVID-19 cases declined by around 42% between September 25 and October 22, 2023, compared to the previous 28-day period, with over 500,000 new cases reported. Deaths decreased by 43% over the same span, with over 4,700 fatalities. As of October 22, 2023, more than 771 million cases and over 6 million deaths have been reported globally.

Paxlovid is taken orally for 5 days. It begins working as soon as you start the treatment, but symptom improvement may not be immediate. Many people notice relief within 1–2 days, though full resolution can take several more days. Some individuals experience lingering symptoms such as fatigue, cough, or shortness of breath for weeks to months. Paxlovid reduces the risk of hospitalization and may lower the chance of developing long COVID.

Paxlovid FAQs

What is Paxlovid?

Paxlovid combines two antiviral drugs and is approved under an FDA Emergency Use Authorization (EUA) to treat mild-to-moderate COVID-19 in people 12 years and older (weighing over 88 lbs) who are at high risk for severe disease. Risk factors include heart disease, lung disease, cancer, diabetes, and obesity.

How does Paxlovid work?

Paxlovid contains nirmatrelvir and ritonavir. Nirmatrelvir is a protease inhibitor that prevents the virus from replicating. Ritonavir, also a protease inhibitor used in HIV treatment, boosts nirmatrelvir levels by slowing its breakdown. Together, they help the immune system control the infection and reduce severe symptoms when taken within 5 days of symptom onset.

What are the side effects of Paxlovid?

Common side effects include:

  • Change in taste
  • Diarrhea

Other possible side effects:

  • Headache
  • High blood pressure
  • Nausea
  • Vomiting
  • Stomach pain

Rare serious side effects may include severe allergic reactions (hives, facial or throat swelling, shortness of breath). Always consult your healthcare provider and read the Medication Guide. Report side effects to the FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

What warnings and precautions are there?

Do not take Paxlovid if you are allergic to nirmatrelvir, ritonavir, or any inactive ingredients. Avoid certain medications that interact seriously; see the patient information for details. Inform your provider if you have:

  • Kidney disease
  • Liver disease (including hepatitis)
  • HIV-1 infection
  • Pregnancy or plans to become pregnant
  • Breastfeeding or plans to breastfeed

Are there any drug interactions?

Paxlovid can alter other drugs’ effects. Inform your provider about all prescription and OTC medications, vitamins, and supplements. Drugs metabolized by CYP3A (certain statins, blood thinners, antiarrhythmics, immunosuppressants, migraine medications, antidepressants) may interact. See the FDA fact sheet for a full list.

How do you take Paxlovid?

Take exactly as prescribed: two pink nirmatrelvir tablets plus one white-to-off-white ritonavir tablet together twice daily for 5 days. Start within 5 days of symptom onset. Swallow whole; do not break or chew. Take with or without food. Complete the full 5-day course even if you feel better.

If you miss a dose and it’s within 8 hours, take it immediately. If more than 8 hours have passed, skip it and take the next dose as scheduled. For overdose, contact your doctor or go to the nearest emergency department immediately.

Am I contagious while taking Paxlovid?

You remain contagious while on Paxlovid. Follow all quarantine and isolation guidelines provided with your positive test result.

What is the cost of Paxlovid?

Paxlovid is free through patient assistance programs for Medicare and Medicaid beneficiaries until end of 2024. It remains free for uninsured and underinsured individuals through 2028. For private insurance, Pfizer set the price at $1,390 per treatment course as of October 13, 2023. Out-of-pocket costs vary by plan. Copay assistance is available through 2028.

How long does Paxlovid stay in your system?

After the 5-day treatment, Paxlovid is typically cleared from the body within about 24 hours.

How effective is Paxlovid?

Early trials showed up to an 89% reduction in risk of hospitalization or death compared to placebo in high-risk patients. Paxlovid remains active against the EG.5 Omicron subvariant. Ongoing research will assess efficacy against future variants.

What can I take instead of Paxlovid?

Alternatives include the monoclonal antibody Veklury (remdesivir) or the antiviral pill Lagevrio (molnupiravir). Consult your healthcare provider to determine the best option.

Does Paxlovid cause COVID rebound?

COVID rebound refers to recurrence of symptoms or a positive test after initial recovery. It can occur 2–8 days post-recovery and affects both treated and placebo groups. Studies report rebound in 2.3% of Paxlovid recipients versus 1.7% on placebo, and in another study 14% versus 9%, respectively.

Related Medications

  • Veklury (remdesivir)
  • Lagevrio (molnupiravir)

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