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Frequently asked questions
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What is Emergency Use Authorization?
According to the U.S. Food and Drug Administration (FDA), an Emergency Use Authorization (EUA) is a mechanism to facilitate the availability and use of medical countermeasures during public health emergencies, such as the current COVID-19 pandemic. Under an EUA, the FDA may allow the use of unapproved medical products, or unapproved uses of approved medical products in an emergency to diagnose, treat, or prevent serious or life-threatening diseases or conditions when certain statutory criteria have been met, including that there are no adequate, approved, and available alternatives. Taking into consideration input from the FDA, manufacturers decide whether and when to submit an EUA request to the FDA. Once submitted, the FDA will evaluate an emergency use authorization request and determine whether the relevant statutory criteria are met, taking into account the totality of the scientific evidence that is available to the FDA.
For more information see:
- View the FDA letter granting EUA of PAXLOVID. For more information about the EUA of PAXLOVID, see the Fact Sheet for Healthcare Providers.
Who can be treated with PAXLOVID under the EUA?
The U.S. Food and Drug Administration (FDA) has issued an Emergency Use Authorization (EUA) for the emergency use of PAXLOVID for the treatment of pediatric patients (12 years of age and older weighing at least 40 kg) with mild-to-moderate coronavirus disease 2019 (COVID-19) and who are at high risk for progression to severe COVID‑19, including hospitalization or death.1
Limitations of Authorized Use
PAXLOVID is not authorized for use as pre-exposure or post-exposure prophylaxis for prevention of COVID‑19.1
The emergency use of PAXLOVID is only authorized for the duration of the declaration that circumstances exist justifying the authorization of the emergency use of drugs and biological products during the COVID-19 pandemic under Section 564(b)(1) of the Act, 21 U.S.C. § 360bbb-3(b)(1), unless the declaration is terminated or authorization revoked sooner.1
For more information:
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How does PAXLOVID work?
PAXLOVID consists of nirmatrelvir and ritonavir. Nirmatrelvir is a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antiviral drug. Ritonavir is an HIV-1 protease inhibitor but is not active against SARS-CoV-2 Mpro. Ritonavir inhibits the CYP3A-mediated metabolism of nirmatrelvir, resulting in increased plasma concentrations of nirmatrelvir.1
For more information:
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Can pharmacists prescribe PAXLOVID?
Under the Eleventh Amendment to the COVID PREP Act declaration, which preempts state law, pharmacists can continue to prescribe PAXLOVID, consistent with the terms of the FDA emergency use authorization (EUA) as specified in the EUA Fact Sheets and the conditions of the PREP Act declaration only while distribution of federally purchased supply continues.
Once the PREP Act coverage has sunset, pharmacists may prescribe PAXLOVID in accordance with the laws of the states in which they practice to eligible patients consistent with the final FDA-approved USPI.
This guidance is based on Pfizer’s interpretation of the PREP Act, the FDA’s EUA of PAXLOVID, and state authorities. These points are for consideration only; each stakeholder should seek advice of counsel.
Do pharmacists have the authority to prescribe PAXLOVID even though the Public Health Emergency (PHE) ended on May 11, 2023?
Why do we need state legislation to grant pharmacists the authority to prescribe PAXLOVID?
How soon after my patient receives a positive test for SARS-CoV-2 should they initiate treatment with PAXLOVID?
The 5-day treatment course of PAXLOVID should be initiated as soon as possible after a diagnosis of COVID‑19 has been made and within 5 days of symptom onset.1
For more information:
What type of COVID-19 test is required to prescribe PAXLOVID?
Patients can take any available FDA-authorized COVID-19 viral test (eg, RT-PCR, rapid antigen, etc) to determine if they may have COVID-19. Per the Centers for Disease Control and Prevention (CDC), a viral test checks specimens from a patient’s nose or mouth and can be performed in a laboratory, at a testing site, at home, or anywhere else.
For more information on COVID-19 testing, see the CDC’s “COVID-19 Testing: What You Need to Know” web page.‡
‡This link will take you to a web page that is owned and operated by the CDC. Pfizer is not responsible for the content or services of this site.
What risk factors put my patients at high risk for severe COVID-19, even when their symptoms are mild?
Important risk factors for consideration are age and race and ethnicity. Studies have shown that COVID-19 does not affect all populations equally. Age is the strongest risk factor for progressing to severe COVID-19. In addition, the COVID-19 pandemic has highlighted racial, ethnic, and socioeconomic disparities in COVID-19 illnesses, hospitalizations, and deaths due to multiple factors, including barriers to accessing healthcare.2
Underlying medical conditions associated with high risk for severe COVID-19 include2:
Higher risk (conclusive):
- Asthma
- Cancer
- Cerebrovascular disease
- Chronic kidney disease
- Chronic lung diseases limited to:
- Bronchiectasis
- COPD
- Interstitial lung disease
- Pulmonary embolism
- Pulmonary hypertension
- Chronic liver diseases limited to:
- Cirrhosis
- Nonalcoholic fatty liver disease
- Alcoholic liver disease
- Autoimmune hepatitis
- Cystic fibrosis
- Diabetes mellitus, type 1 and type 2
- Disabilities, including Down syndrome§
- Heart conditions (such as heart failure, coronary artery disease, or cardiomyopathies)
- HIV
- Mental health conditions limited to:
- Mood disorders, including depression
- Schizophrenia spectrum disorders
- Neurologic conditions limited to dementia
- Obesity (BMI ≥30 kg/m² or ≥95th percentile in children)
- Physical inactivity
- Pregnancy and recent pregnancy
- Primary immunodeficiencies
- Smoking, current and former
- Solid organ or blood stem cell transplant
- Tuberculosis
- Use of corticosteroids or other immunosuppressive medications
Suggestive higher risk:
- Children with certain underlying conditions
- Overweight (BMI ≥25 kg/m², but <30 kg/m²)
- Sickle cell disease
- Substance use disorders
Mixed evidence (inconclusive: no conclusions can be drawn from the evidence):
- Alpha-1 antitrypsin deficiency
- Bronchopulmonary dysplasia
- Hepatitis B and C
- Hypertension
- Thalassemia
Patients at high risk of severe COVID-19 may be appropriate for an authorized oral prescription COVID-19 treatment. Authorized oral prescription treatment must be started within 5 days from when symptoms begin—even when initial symptoms are mild.1
Consult the CDC for the latest information on risk factors.
§Complete list of disabilities from the CDC’s systematic review process can be found CDC underlyingconditions here.¶
¶This link will take you to a website that is owned and operated by the CDC. Pfizer is not responsible for the content or services of this site.
How should I write a prescription for PAXLOVID?
Prescriptions should specify the numeric dose of each active ingredient in PAXLOVID. Providers should also specify that completion of the full 5-day treatment course and continued isolation in accordance with public health recommendations are important to maximize viral clearance and minimize transmission of SARS-CoV-2.1
The pharmacy may also require information about the patient’s comorbidities, current medications, ethnicity, and blood labs for renally impaired patients.
Write or e-prescribe#:
- Standard dosing for PAXLOVID is 300 mg nirmatrelvir and 100 mg ritonavir twice daily for 5 days
- Reduced dose for PAXLOVID is 150 mg nirmatrelvir and 100 mg ritonavir twice daily for 5 days
Refer to the FDA’s PAXLOVID Screening Eligibility Checklist for Prescribers for information to support clinical decision-making.
#Note: It is important to know your state, institutional, and local requirements when writing a prescription for PAXLOVID. For example, some pharmacies only accept e-prescriptions and/or mandate other information be included in the prescription, such as the patient’s risk factor(s) and/or concomitant medications.
For more information:
When prescribing PAXLOVID, what type of information is recommended to include on the e-prescription?
In addition to specifying the numeric dose of each active ingredient within PAXLOVID and the dosage form, here are other common details to include**:
For patients with moderate renal impairment, the numeric dose will be 150 mg nirmatrelvir and 100 mg ritonavir taken together twice daily with or without food for 5 days.
Please fill prescription by [insert date].
[Additional notes to pharmacy for Standard Dose]
- Risk factor(s) for progression to severe COVID-19††
- Symptom onset ≤5 days, consistent with mild-to-moderate COVID-19, not requiring hospitalization
- No known/suspected renal impairment (eGFR ≥90 mL/min) OR patient has moderate renal impairment (eGFR ≥60 mL/min to <90 mL/min)
- No known or suspected severe (Child-Pugh Class C) hepatic impairment
- No history of significant hypersensitivity reactions
- Concomitant medications (screen for drug interactions)
Notes above depict considerations for prescribing after the decision to prescribe has been made; examples shown are for illustrative purposes only as prescribing notes are subject to the healthcare provider’s discretion.
Providers should also specify that completion of the full 5-day treatment course and continued isolation in accordance with public health recommendations are important to maximize viral clearance and minimize transmission of SARS-CoV-2.
**For additional screening information, consult the FDA’s PAXLOVID Patient Eligibility Screening Checklist Tool for Prescribers‡‡ or a similar resource from your local public health authority.
††Consult the CDC‡‡ for the latest information on factors that put patients at high risk for progression to severe COVID-19.
‡‡These links will take you to websites that are owned and operated by the FDA and CDC. Pfizer is not responsible for the content or services of these sites.
For more information:
Can I prescribe PAXLOVID to pregnant patients?
There are no available human data on the use of nirmatrelvir during pregnancy to evaluate for a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. Published observational studies on ritonavir use in pregnant women have not identified an increase in the risk of major birth defects. Published studies with ritonavir are insufficient to identify a drug-associated risk of miscarriage. There are maternal and fetal risks associated with untreated COVID-19 in pregnancy.1
For more information on the use of PAXLOVID during pregnancy, see Section 8.1 of the FACT SHEET FOR HEALTHCARE PROVIDERS.
How much will my patients pay for PAXLOVID?
How do patients take PAXLOVID?
PAXLOVID consists of 2 medicines: nirmatrelvir and ritonavir. Nirmatrelvir must be coadministered with ritonavir. Failure to correctly coadminister nirmatrelvir with ritonavir may result in plasma levels of nirmatrelvir that are insufficient to achieve the desired therapeutic effect.
- Patients should take 2 tablets of nirmatrelvir (150 mg each) with 1 tablet of ritonavir (100 mg) by mouth twice daily (in the morning and in the evening) for 5 days. For each dose, all 3 tablets should be taken at the same time
- Patients should swallow the tablets whole. They should not chew, break, or crush the tablets
- Patients can take PAXLOVID with or without food
- Even if patients feel better, they should not stop taking PAXLOVID without talking to the prescribing healthcare provider
- Alert the patient to the importance of completing the full 5-day treatment course and continuing isolation in accordance with public health recommendations to maximize viral clearance and minimize transmission of SARS-CoV-2
- To ensure appropriate dosing in patients with moderate renal impairment, reduce the dosage of PAXLOVID to 150 mg nirmatrelvir and 100 mg ritonavir twice daily for 5 days. Providers should counsel patients about renal dosing instructions
For more information on how to take PAXLOVID, patients can refer to the Patient Information Patient Information here
What if patients take PAXLOVID incorrectly?
Missed dose1
- Within 8 hours of the time it is usually taken: the patient should take it as soon as possible and resume the normal dosing schedule
- More than 8 hours: the patient should not take the missed dose and instead take the next dose at the regularly scheduled time. The patient should not double the dose to make up for a missed dose
Overdose
If patients overdose on PAXLOVID, they should call their prescribing healthcare provider or go to the nearest hospital emergency room right away.
For more information:
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Who can I call with medical questions?
What are the contraindications for PAXLOVID?
WARNING: SIGNIFICANT DRUG INTERACTIONS WITH PAXLOVID1
- PAXLOVID includes ritonavir, a strong CYP3A inhibitor, which may lead to greater exposure of certain concomitant medications, resulting in potentially severe, life-threatening, or fatal events
- Prior to prescribing PAXLOVID: 1) Review all medications taken by the patient to assess for potential drug-drug interactions with a strong CYP3A inhibitor like PAXLOVID and 2) Determine if concomitant medications require a dose adjustment, interruption, and/or additional monitoring
- Consider the benefit of PAXLOVID treatment in reducing hospitalization and death, and whether the risk of potential drug-drug interactions for an individual patient can be appropriately managed
PAXLOVID is contraindicated in/with1:
- Patients with a history of clinically significant hypersensitivity reactions (eg, toxic epidermal necrolysis (TEN) or Stevens-Johnson syndrome) to its active ingredients (nirmatrelvir or ritonavir) or any other components of the product
- Drugs that are highly dependent on CYP3A for clearance and for which elevated concentrations are associated with serious and/or life-threatening reactions
- Drugs that are potent CYP3A inducers where significantly reduced nirmatrelvir or ritonavir plasma concentrations may be associated with the potential for loss of virologic response and possible resistance
For more information, including clinically significant drug interactions:
What are the potential drug interactions with PAXLOVID?
WARNING: SIGNIFICANT DRUG INTERACTIONS WITH PAXLOVID1
- PAXLOVID includes ritonavir, a strong CYP3A inhibitor, which may lead to greater exposure of certain concomitant medications, resulting in potentially severe, life-threatening, or fatal events
- Prior to prescribing PAXLOVID: 1) Review all medications taken by the patient to assess for potential drug-drug interactions with a strong CYP3A inhibitor like PAXLOVID and 2) Determine if concomitant medications require a dose adjustment, interruption, and/or additional monitoring
- Consider the benefit of PAXLOVID treatment in reducing hospitalization and death, and whether the risk of potential drug-drug interactions for an individual patient can be appropriately managed
PAXLOVID (nirmatrelvir co-packaged with ritonavir) is a strong inhibitor of CYP3A, and an inhibitor of CYP2D6, P-gp, and OATP1B1. Coadministration of PAXLOVID with drugs that are primarily metabolized by CYP3A and CYP2D6 or are transported by P-gp or OATP1B1 may result in increased plasma concentrations of such drugs and increase the risk of adverse events. Coadministration of PAXLOVID with drugs highly dependent on CYP3A for clearance and for which elevated plasma concentrations are associated with serious and/or life-threatening events is contraindicated. Coadministration with other CYP3A substrates may require a dose adjustment or additional monitoring as shown in this table.1
Nirmatrelvir and ritonavir are CYP3A substrates; therefore, drugs that induce CYP3A may decrease nirmatrelvir and ritonavir plasma concentrations and reduce PAXLOVID therapeutic effect.1
For more information:
Is there information about viral RNA rebound with PAXLOVID?
BMI=body mass index; COPD=chronic obstructive pulmonary disease; COVID-19=coronavirus disease 2019; eGFR=estimated glomerular filtration rate; HIV=human immunodeficiency virus; Mpro=main protease; RNA=ribonucleic acid; RT-PCR=reverse transcription-polymerase chain reaction; SARS-CoV-2=severe acute respiratory syndrome coronavirus 2.
References:
- Fact Sheet for Healthcare Providers: Emergency Use Authorization for PAXLOVID™. Pfizer Inc.; 2024.
- Underlying medical conditions associated with higher risk for severe COVID-19: information for healthcare providers. Centers for Disease Control and Prevention. February 9, 2023. Accessed January 25, 2024. https://www.cdc.gov/coronavirus/2019-ncov/hcp/clinical-care/underlyingconditions.html