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Details for: PAXLOVID - COVID-19


DIN DIN name Active Ingredient(s) Strength Dosage Form Route of Administration

Summary Reports

Regulatory Decision Summary
Product Monograph

Consumer Information

This information was provided by the drug’s manufacturer when this drug product was approved for sale in Canada. It is designed for consumers and care givers. It is a summary of information about the drug and will not tell you everything about the drug. Contact your doctor or pharmacist if you have any questions about the drug.

What the medication is used for

PAXLOVID is used in adults to treat mild to moderate coronavirus disease 2019 (COVID-19) in patients who:

  • have a positive result from a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral test and
  • who have a high risk of getting severe COVID-19, including hospitalization or death.

PAXLOVID IS NOT approved for any of the following:

  • To treat patients who are hospitalized due to severe or critical COVID-19.
  • To prevent COVID-19.
  • To be used for longer than 5 days in a row.
  • For use in children and adolescents less than 18 years of age.
What it does

COVID-19 is caused by a virus called a coronavirus. PAXLOVID contains two antiviral medicines co-packaged together, nirmatrelvir and ritonavir. PAXLOVID stops the virus from multiplying. This can help your body to overcome the virus infection and may help you get better faster.

When it should not be used

Do not use PAXLOVID if:

  • You are allergic to nirmatrelvir, ritonavir or to any of the other ingredients in PAXLOVID (see What the medicinal ingredient is or What the non-medicinal ingredients are).
  • You are taking any of the following medicines:
    • alfuzosin, used to treat high blood pressure
    • amiodarone, bepridil*, dronedarone, flecainide, propafenone, quinidine, used to treat irregular heartbeats
    • apalutamide, used for prostate cancer
    • astemizole* or terfenadine*, used to relieve allergy symptoms
    • cisapride*, used to relieve certain stomach problems
    • colchicine, when used in patients with kidney and/or liver problems, used to treat gout
    • ergotamine*, dihydroergotamine (used to treat headaches), ergonovine, methylergonovine* (used after labour and delivery)
    • fusidic acid, used as an antibiotic
    • lovastatin, lomitapide or simvastatin, used to lower cholesterol
    • lurasidone, pimozide, used to treat mental health problems
    • neratinib, used to treat breast cancer
    • ranolazine, used to treat chronic angina (chest pain)
    • rifampin and saquinavir, used to treat tuberculosis, should not be used together with ritonavir
    • rivaroxaban, used as an anticoagulant
    • salmeterol, used for asthma and chronic obstructive pulmonary disease
    • St. John’s Wort (Hypericum perforatum), an herbal product used to treat depression
    • triazolam and midazolam* (oral or injected), used to relieve anxiety and/or trouble sleeping
    • PDE5 inhibitors vardenafil, used to treat erectile dysfunction, or sildenafil, used for the treatment of pulmonary arterial hypertension (PAH)
    • voriconazole, used as an antifungal
    • venetoclax during the dose initiation and during the ramp-up phase, used to treat chronic lymphocytic leukemia
    • carbamazepine, phenobarbital, phenytoin used to treat seizures (epilepsy)

    * Product is not or no longer marketed in Canada

What the medicinal ingredient is

Medicinal ingredients: nirmatrelvir.


Medicinal ingredients: ritonavir.

What the non-medicinal ingredients are


Non-medicinal ingredients: colloidal silicon dioxide, croscarmellose sodium, lactose monohydrate, microcrystalline cellulose, and sodium stearyl fumarate. The film-coating contains hydroxy propyl methylcellulose, iron oxide red, polyethylene glycol and titanium dioxide.


Non-medicinal ingredients in ritonavir: anhydrous dibasic calcium phosphate, colloidal silicon dioxide, copovidone, sodium stearyl fumarate, and sorbitan monolaurate. The film-coating contains colloidal silicon dioxide, hydroxypropyl cellulose, hypromellose, polyethylene glycol, polysorbate 80, talc and titanium dioxide.

What dosage form it comes in

PAXLOVID consists of two medicines co-packaged together:

  • Nirmatrelvir (pink tablet): 150 mg
  • Ritonavir (white tablet): 100 mg

Each carton contains 5 blister cards. Each blister card contains 6 tablets: 4 pink tablets (150 mg nirmatrelvir) and 2 white tablets (100 mg ritonavir).

Warnings and precautions

Serious Warnings and Precautions

Patients with kidney problems: Tell your healthcare professional before you take PAXLOVID if you have any kidney problems. You might need a lower dose of PAXLOVID. Your healthcare professional will prescribe a dose that is right for you.

Serious interactions with other medicines: Many medicines interact with PAXLOVID. Taking PAXLOVID with these medicines may cause serious or life-threatening side effects. Tell your healthcare professional about all the medicines you take before you start taking PAXLOVID. Do not take PAXLOVID if you are taking any of the medicines listed under the “Do not use PAXLOVID if:” section, below. Talk to your healthcare professional first before taking any new medicines. They will tell you if it is safe to take.

To help avoid side effects and ensure proper use, talk to your healthcare professional before you take PAXLOVID. Talk about any health conditions or problems you may have, including if you:

  • Have kidney problems
  • Have liver problems including hepatitis
  • Have human immunodeficiency virus (HIV) infection

Other warnings you should know about:

Liver problems:

Before you take PAXLOVID tell your healthcare professional if you have any liver problems. Liver problems have happened in patients taking ritonavir, a medicine in PAXLOVID. Talk to your healthcare professional if you get any symptoms of liver problems. These include: yellow skin or whites of eyes, nausea, tiredness or feeling unwell, loss of appetite, fever, skin rash, abdominal pain, pale stool or dark coloured urine.

Pregnancy and Contraception: Tell your healthcare professional if you are pregnant, think you might be pregnant or are planning to become pregnant. You should not take PAXLOVID if you are pregnant unless your healthcare professional advises that you can. Women should use effective contraception while they are taking PAXLOVID. PAXLOVID may affect how birth control pills, patches and vaginal rings work. You should use alternate contraception or an additional barrier method such as a condom while you are taking PAXLOVID. Talk to your healthcare professional about effective methods of birth control.

Breastfeeding: Tell your healthcare professional if you are breastfeeding or plan to breastfeed. PAXLOVID can pass into your breastmilk. Your healthcare professional will tell you if you can breastfeed your baby while taking PAXLOVID.

Tell your healthcare professional about all the medicines you take, including any drugs, vitamins, minerals, natural supplements or alternative medicines.

Do not take PAXLOVID if you are taking any of the medicines listed under the “When it should not be used” section.
Taking PAXLOVID with these medicines may cause serious or life-threatening side effects.

Interactions with this medication

The following may also interact with PAXLOVID:

  • medicines used to treat erectile dysfunction, such as tadalafil
  • medicines used to treat pulmonary arterial hypertension, such as bosentan or tadalafil
  • medicines used to lower blood cholesterol, such as atorvastatin and rosuvastatin
  • some medicines affecting the immune system, such as cyclosporin, sirolimus and tacrolimus
  • some medicines used to treat seasonal allergies and ear and eye infections, such as budesonide, dexamethasone, fluticasone propionate, prednisone, and triamcinolone
  • medicines used to treat AIDS and related infections, such as amprenavir, indinavir*, nelfinavir, saquinavir, didanosine*, rifabutin, tipranavir, delavirdine*, atazanavir, maraviroc, fosamprenavir, raltegravir, tenofovir and darunavir
  • medicines used to treat depression, such as trazodone, desipramine and bupropion
  • certain heart medicines, such as calcium channel antagonists including diltiazem, nifedipine and verapamil
  • medicines used to correct heart rhythm, such as systemic lidocaine and digoxin
  • antifungals, such as ketoconazole and itraconazole*
  • morphine-like medicines used to treat severe pain, such as methadone and meperidine
  • anticoagulants, such as warfarin
  • certain antibiotics, such as rifabutin and clarithromycin
  • antibiotics used in the treatment of tuberculosis, such as rifampin
  • bronchodilators used to treat asthma, such as theophylline
  • medicines used to treat cancer, such as abemaciclib, dasatinib, encorafenib, ibrutinib, nilotinib, vincristine and vinblastine
  • medicines used for low blood platelet count, such as fostamatinib
  • some heart rhythm drugs, such as mexiletine and disopyramide
  • some anticonvulsants, such as clonazepam, divalproex, lamotrigine and ethosuximide
  • some narcotic analgesics, such as fentanyl in all forms, tramadol and propoxyphene
  • quetiapine used to treat schizophrenia, bipolar disorder and major depressive disorder
  • medicines used to treat hepatitis C, such as simeprevir, glecaprevir/pibrentasvir or ombitasvir, paritaprevir and ritonavir with or without dasabuvir*
  • some sedatives or medicines to treat anxiety, such as buspirone, clorazepate, diazepam, flurazepam and zolpidem
  • stimulants, such as methamphetamine
  • medicines used to treat pain associated with endometriosis, such as elagolix
  • medicines used to treat depression, such as amitriptyline, clomipramine, fluoxetine, imipramine, maprotiline*, nefazodone*, nortriptyline, paroxetine, sertraline, trimipramine
  • medicines used to treat nausea and vomiting, such as dronabinol*
  • medicines used to treat pneumonia, such as atovaquone
  • medicines used as a sedative and medicines used to help you sleep (hypnotics), such as estazolam
  • medicines used to treat increased pressure in the eye, such as timolol
  • medicines used to lower blood pressure, such as metoprolol
  • medicines used to treat HIV, such as efavirenz
  • medicines used to prevent organ rejection after a transplant, such as everolimus, rapamycin
  • medicines used to treat certain mental/mood disorders such as schizophrenia, bipolar disorder, such as perphenazine, risperidone and thioridazine
  • medicines used as hormonal contraceptives containing ethinyl estradiol (“the pill”)

* Product is not or no longer marketed in Canada.

Proper use of this medication

How to take PAXLOVID:

  • PAXLOVID consists of two medicines co-packaged together:
    • nirmatrelvir (pink tablet)
    • ritonavir (white tablet)
  • You must always take the nirmatrelvir tablets at the same time as the ritonavir tablet.
  • Always take PAXLOVID exactly as your healthcare professional has told you to.
  • Check with your healthcare professional if you are not sure.
  • You can take PAXLOVID with or without food.
  • Swallow the tablets whole. Do not break, chew or crush the tablets.
  • You must take PAXLOVID for 5 days in a row. Complete the entire 5 day treatment with PAXLOVID.
  • Even if you feel better, do not stop taking PAXLOVID without talking to your healthcare professional first.
  • Talk to your doctor if you do not feel better or if you feel worse after 5 days.
  • If you have kidney problems, talk to your healthcare professional. You may need to take a lower dose.

Usual Dose:

Adults: Take 2 pink nirmatrelvir tablets and 1 white ritonavir tablet. Take these 3 tablets at the same time, twice a day (in the morning and again in the evening) for 5 days.

Each blister card shows your morning and evening dose, as follows:

If you have kidney problems, talk to your healthcare professional. You may need to take a lower dose.


If you think you, or a person you are caring for, have taken too much PAXLOVID, contact a healthcare professional, hospital emergency department, or regional poison control centre immediately, even if there are no symptoms.

Missed Dose

If you miss taking your dose and it:

  • is within 8 hours of the time it is usually taken, take it as soon as you remember.
  • has been more than 8 hours, skip the missed dose and take the next dose at your regular time.

Do not take 2 doses of PAXLOVID at the same time.

Side effects and what to do about them

These are not all the possible side effects you may have when taking PAXLOVID. If you experience any side effects not listed here, tell your healthcare professional.

Side effects may include:

  • altered sense of taste
  • diarrhea
  • muscle pain
  • vomiting
  • high blood pressure
  • headache

Not many people have taken PAXLOVID. Serious and unexpected side effects may happen. PAXLOVID is still being studied, so it is possible that all the side effects are not known at this time.

If you have a troublesome symptom or side effect that is not listed here or becomes bad enough to interfere with your daily activities, tell your healthcare professional.

How to store

Storage: Store at room temperature 15°C to 30°C.

Keep out of reach and sight of children.

Reporting side effects

You can report any suspected side effects associated with the use of health products to Health Canada by:

NOTE: Contact your health professional if you need information about how to manage your side effects. The Canada Vigilance Program does not provide medical advice.

More information

If you want more information about PAXLOVID:

This leaflet was prepared by Pfizer Canada ULC.

Last Revised January 17, 2022

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