What is NIRMATRELVIR used for?

NIRMATRELVIR (as Paxlovid) treats mild-to-moderate COVID-19 in adults who are at high risk of becoming very sick.

Can I take NIRMATRELVIR to prevent COVID-19?

No, NIRMATRELVIR is not approved to prevent COVID-19 before you are exposed or after you have been exposed.

How should I take NIRMATRELVIR?

You should take the tablets twice daily for 5 days, ideally at the same time each day, with or without food.

What are the most common side effects of NIRMATRELVIR?

The most common side effects reported are a change in taste (dysgeusia) and diarrhea.

Is NIRMATRELVIR safe to take if I have kidney disease?

Doses may need to be adjusted for people with moderate kidney impairment, and specific instructions apply for severe impairment.

Can NIRMATRELVIR interact with my other medicines?

Yes, NIRMATRELVIR has many significant drug interactions that could be life-threatening; always review your medications with a professional.

What should I do if I have an allergic reaction to NIRMATRELVIR?

If you show signs of a serious allergic reaction, stop taking the medicine immediately and seek medical care.

Is NIRMATRELVIR safe during pregnancy?

There is not enough data to determine the risk of birth defects or miscarriage from NIRMATRELVIR use during pregnancy.

nirmatrelvir | CAS 2628280-40-8 | LIENCHBZNNMNKG

Loading compound...

Antiviral (SARS-CoV-2 main protease inhibitor)

NIRMATRELVIR (brand name Paxlovid) is an oral medication used to treat mild-to-moderate COVID-19 in adults who are at high risk of getting very sick. It is a combination pill that contains nirmatrelvir and ritonavir. It must be taken exactly as prescribed, usually for 5 days, and is not meant to prevent COVID-19 before or after exposure.

How it worksNirmatrelvir works by blocking a specific protein (3C-like proteinase) that the SARS-CoV-2 virus needs to replicate. Ritonavir is included to slow down how the body breaks down nirmatrelvir, which helps keep the medicine at effective levels in your system.

Brand names:PAXLOVID (COPACKAGED)

Used for

Treatment of mild-to-moderate COVID-19 in adults at high risk for severe disease, including hospitalization or death

Conditions

COVID-19

Class

AntiviralProtease InhibitorAntiviral (SARS-CoV-2 main protease inhibitor)Respiratory

How to take

FormsOral tablets

RoutesOral

The standard dose is two 150 mg nirmatrelvir tablets and one 100 mg ritonavir tablet, taken together twice daily for 5 days. People with kidney issues may need a different dose.

Take the medication at approximately the same time each day. It can be taken with or without food.

Missed dose: If you miss a dose, the label does not specify a correction; however, it emphasizes taking doses at approximately the same time each day.

Key warnings

PAXLOVID can cause serious, life-threatening, or fatal reactions when taken with certain other medicines because it significantly changes how those drugs are processed in your body.

·PAXLOVID can cause serious, life-threatening, or fatal reactions when taken with certain other medicines because it significantly changes how those drugs are processed in your body.
·Significant drug interactions with many other medications.
·Risk of severe hypersensitivity or allergic reactions.
·Potential for liver injury.
·Risk of HIV-1 drug resistance in patients with undiagnosed or uncontrolled HIV-1.

Do not use if

·Do not use if you have had a serious allergic reaction to nirmatrelvir or ritonavir.
·Do not use with drugs that are primarily broken down by the CYP3A enzyme if high levels of those drugs cause serious or life-threatening reactions.
·Do not use with strong CYP3A inducer drugs, as this may make the treatment fail.

Side effects

Common

Altered sense of taste (dysgeusia)Diarrhea

Serious

·Severe allergic reactions (anaphylaxis or serious skin reactions like Stevens-Johnson syndrome)
·Liver problems (hepatotoxicity)
·Risk of HIV-1 drug resistance in people with uncontrolled HIV

Seek help if

·nirmatrelvir drug interactions

Interactions

·PAXLOVID can change the amount of other drugs in your blood, making them potentially dangerous.
·It should not be used with drugs that are strongly activated by the CYP3A enzyme.
·Common interacting drugs mentioned include REXULTI, ONMEL, DESOWEN, CRESEMBA, NORVIR, EXTINA, RIFADIN, VERZENIO, LUPKYNIS, and SELZENTRY.

FoodCan be taken with or without food.

Special populations

PregnancyThere is not enough information to know if nirmatrelvir is safe during pregnancy. While studies on ritonavir haven't shown major birth defect risks, untreated COVID-19 itself carries risks to both the mother and the baby.

PediatricThe correct dose for children has not been established.

GeriatricStudies included adults aged 65 and older, and no major safety differences were found compared to younger people.

Talk to your doctor

Monitor

·Signs of allergic reaction
·Liver function
·Symptoms of other drug interactions

Questions to ask

·Are any of my current medications unsafe to take with NIRMATRELVIR?
·Do I need a dose adjustment due to my kidney function?
·What should I do if I experience a change in taste or diarrhea?

Pharmacokinetics

OnsetNirmatrelvir steady state is achieved on Day 2.

MetabolismRitonavir inhibits the CYP3A-mediated metabolism of nirmatrelvir.

Practical

OverdoseThere is no specific antidote for an overdose. Treatment involves general medical support, such as monitoring vital signs and clinical status.

StorageStore at room temperature between 68°F to 77°F (20°C to 25°C).

Ingredients

Allergens

lactose

Inactive

colloidal silicon dioxidecroscarmellose sodiumlactose monohydratemicrocrystalline cellulosesodium stearyl fumaratehydroxy propyl methylcelluloseiron oxide redpolyethylene glycoltitanium dioxideanhydrous dibasic calcium phosphatecopovidone K25-31sorbitan monolauratehydroxypropyl cellulosepolysorbate 80talc

Educational summary derived from FDA labeling, AI-assisted. Not medical advice — consult a healthcare professional. Updated 2026-04-25.