(nirmatrelvir tablets; ritonavir tablets)
PAXLOVID is nirmatrelvir tablets co-packaged with ritonavir tablets. Nirmatrelvir is a SARS-CoV-2 main protease (Mpro) inhibitor, and ritonavir is an HIV-1 protease inhibitor and CYP3A inhibitor.
Nirmatrelvir
The chemical name of active ingredient of nirmatrelvir is (1R,2S,5S)-N-((1S)-1-Cyano-2-((3S)-2-oxopyrrolidin-3-yl)ethyl)-3-((2S)-3,3-dimethyl-2-(2,2,2-trifluoroacetamido)butanoyl)-6,6-dimethyl-3-azabicyclo[3.1.0]hexane-2-carboxamide]. It has a molecular formula of C23H32F3N5O4 and a molecular weight of 499.54. Nirmatrelvir has the following structural formula:
Nirmatrelvir is available as immediate-release, film-coated tablets. Each tablet contains 150 mg nirmatrelvir with the following inactive ingredients: colloidal silicon dioxide, croscarmellose sodium, lactose monohydrate, microcrystalline cellulose, and sodium stearyl fumarate. The following are the ingredients in the film coating: hydroxy propyl methylcellulose, iron oxide red, polyethylene glycol, and titanium dioxide.
Ritonavir
Ritonavir is chemically designated as 10-Hydroxy-2-methyl-5-(1-methylethyl)-1- [2-(1 methylethyl)-4-thiazolyl]-3,6-dioxo-8,11-bis(phenylmethyl)-2,4,7,12- tetraazatridecan-13-oic acid, 5-thiazolylmethyl ester, [5S-(5R*,8R*,10R*,11R*)]. Its molecular formula is C37H48N6O5S2, and its molecular weight is 720.95. Ritonavir has the following structural formula:
Ritonavir is available as film-coated tablets. Each tablet contains 100 mg ritonavir with the following inactive ingredients: anhydrous dibasic calcium phosphate, colloidal silicon dioxide, copovidone, sodium stearyl fumarate, and sorbitan monolaurate. The film coating may include the following ingredients: colloidal anhydrous silica, colloidal silicon dioxide, hydroxypropyl cellulose, hypromellose, polyethylene glycol, polysorbate 80, talc, and titanium dioxide.
PATIENT INFORMATION | ||||||
What is the most important information I should know about PAXLOVID? PAXLOVID can interact with other medicines causing severe or life-threatening side effects or death. It is important to know the medicines that should not be taken with PAXLOVID. Do not take PAXLOVID if:
| ||||||
|
|
| ||||
These are not the only medicines that may cause serious or life-threatening side effects if taken with PAXLOVID. PAXLOVID may increase or decrease the levels of multiple other medicines. It is very important to tell your healthcare provider about all of the medicines you are taking because additional laboratory tests or changes in the dose of your other medicines may be necessary during treatment with PAXLOVID. Your healthcare provider may also tell you about specific symptoms to watch out for that may indicate that you need to stop or decrease the dose of some of your other medicines.
| ||||||
What is PAXLOVID? PAXLOVID is not approved for use as pre-exposure or post-exposure treatment for prevention of COVID-19. | ||||||
Before taking PAXLOVID, tell your healthcare provider about all of your medical conditions, including if you:
Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.
Tell your healthcare provider if you are taking combined birth control (hormonal contraceptive). PAXLOVID may affect how your hormonal contraceptives work. Females who are able to become pregnant should use another effective alternative form of contraception or an additional barrier method of contraception during treatment with PAXLOVID. Talk to your healthcare provider if you have any questions about contraceptive methods that might be right for you. | ||||||
How should I take PAXLOVID?
| ||||||
If you are prescribed PAXLOVID 300 mg; 100 mg Dose Pack | ||||||
![]() | ||||||
How to take PAXLOVID 300 mg; 100 mg Dose Pack | ||||||
![]() | Morning Dose: | |||||
![]() | ||||||
![]() | Bedtime Dose: | |||||
![]() | ||||||
If you are prescribed PAXLOVID 150 mg; 100 mg Dose Pack | ||||||
![]() | ||||||
How to take PAXLOVID 150 mg; 100 mg Dose Pack | ||||||
![]() | Morning Dose: | |||||
![]() | ||||||
![]() | Bedtime Dose: | |||||
![]() | ||||||
If you are prescribed PAXLOVID 300 mg; 100 mg (Day 1) and 150 mg; 100 mg (Days 2-5) | ||||||
![]() | ||||||
How to take PAXLOVID 300 mg; 100 mg (Day 1) and 150 mg; 100 mg (Days 2-5) | ||||||
![]() | Day 1 (First Day): Take the 2 pink nirmatrelvir tablets and | |||||
![]() | Days 2-5: Take the 1 pink nirmatrelvir tablet and 1 white ritonavir tablet together | |||||
Talk to your healthcare provider if you do not feel better or if you feel worse after 5 days. | ||||||
What are the possible side effects of PAXLOVID? PAXLOVID may cause serious side effects, including:
| ||||||
|
| |||||
| ||||||
|
| |||||
The most common side effects of PAXLOVID include: altered sense of taste (such as metallic, bitter taste) and diarrhea. Other possible side effects include:
These are not all of the possible side effects of PAXLOVID. For more information, ask your healthcare provider or pharmacist. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. | ||||||
How should I store PAXLOVID?
Keep PAXLOVID and all medicines out of the reach of children. | ||||||
General information about the safe and effective use of PAXLOVID. | ||||||
What are the ingredients in PAXLOVID? | ||||||
![]() LAB-1524-5.0 | ||||||
This Patient Information has been approved by the U.S. Food and Drug Administration. Revised: 02/2026
Additional Resources
Chat online with Pfizer Medical Information regarding your inquiry on a Pfizer medicine or vaccine.
Speak with a Pfizer Medical Information Professional regarding your Pfizer medicine or vaccine inquiry.
Available 9AM-5PM ET Monday to Friday; excluding holidays.
Submit a medical question for a Pfizer medicine or a vaccine.
The submission will be reviewed during our standard business hours.
To report an adverse event related to a Pfizer product and you are not part of a clinical trial* for this medication, click the link below to submit your information:
Pfizer Safety Reporting Site
*If you are involved in a clinical trial for either product, adverse events should be reported to your coordinating study site.
If you cannot use the above website to report an adverse event related to a Pfizer medication, please call (800) 438-1985.
You may also contact the U.S. Food and Drug Administration (FDA) directly to report adverse events or product quality concerns either online at www.fda.gov/medwatch or by calling (800) 332-1088.