This combination of nirmatrelvir and ritonavir is used to treat coronavirus disease (COVID-19) in people who have mild to moderate symptoms and have a high risk for COVID-19 complications. It helps people who have COVID-19 to stay out of the hospital. It is not for use by people who are hospitalized due to COVID-19.

Nirmatrelvir is a SARS-CoV-2 main protease inhibitor. It works by preventing the growth of the virus that causes COVID-19. Ritonavir increases ("boosts") the levels of nirmatrelvir. This helps nirmatrelvir work better.

This medication works by stopping the coronavirus from growing. It cannot be used to prevent COVID-19.

Read the Patient Information Leaflet if available from your pharmacist before you start taking this product and each time you get a refill. If you have any questions, ask your doctor or pharmacist.

Take this medication by mouth with or without food as directed by your doctor, usually once or twice daily for 5 days. If you are on dialysis, take your dose of this medication after dialysis on your dialysis days. Swallow the tablets whole. Do not chew, break, or crush the tablets. The dosage is based on your medical condition and response to treatment.

This product works best if you start taking it within 5 days of when symptoms begin.

For the best effect, take this product at evenly spaced times. To help you remember, take it at the same times every day.

Continue to take this medication until the full prescribed amount is finished, even if symptoms disappear after a few days. Stopping the medication too early may result in a return of the infection.

Tell your doctor if your condition lasts or gets worse.

Changes in taste or diarrhea may occur. If either of these effects lasts or gets worse, tell your doctor or pharmacist promptly.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including:

• signs of liver problems (such as nausea/vomiting that doesn't stop, loss of appetite, stomach/abdominal pain, yellowing eyes/skin, dark urine)

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before taking this product, tell your doctor or pharmacist if you are allergic to nirmatrelvir or ritonavir; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of:

• kidney disease
• liver disease
• HIV infection

To avoid spreading the virus, you should continue to take precautions such as self-isolation, wearing a mask, social distancing (physical distancing), washing hands, and not sharing personal items.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

During pregnancy, this product should be used only when clearly needed. Discuss the risks and benefits with your doctor.

This medication passes into breast milk. Consult your doctor before breastfeeding.

See also Warning section.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

A product that may interact with this drug is:

• orlistat

Nirmatrelvir/ritonavir can slow down or speed up the removal of other medications from your body, which may affect how they work. Examples of affected drugs include alfuzosin, antiarrhythmics (such as amiodarone, flecainide, propafenone, quinidine), azole antifungals (such as voriconazole), certain benzodiazepines (midazolam, triazolam), certain "blood thinners" (such as rivaroxaban, warfarin), eletriptan, drugs to treat erectile dysfunction-ED or pulmonary hypertension (such as avanafil, sildenafil), ergot alkaloids (such as dihydroergotamine, ergonovine, ergotamine, methylergonovine), lurasidone, certain opioid pain medications (such as fentanyl, meperidine), pimozide, ranolazine, salmeterol, "statin" cholesterol drugs (such as simvastatin, lovastatin), among others.

Other medications can affect the removal of nirmatrelvir/ritonavir from your body, which may affect how this medication works. Examples include apalutamide, butalbital, encorafenib, enzalutamide, lumacaftor, mitotane, certain rifamycins (such as rifampin, rifapentine), St. John's wort, drugs used to treat seizures (such as carbamazepine, phenobarbital, phenytoin), among others.

This medication may decrease the effectiveness of hormonal birth control (containing ethinyl estradiol) such as pills, patch, or ring. This could cause pregnancy. Discuss with your doctor or pharmacist if you should use reliable backup birth control methods while using this medication. Also tell your doctor if you have any new spotting or breakthrough bleeding, because these may be signs that your birth control is not working well.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669.

Do not share this medication with others.

This medication has been prescribed for your current condition only. Do not use it later for another infection unless your doctor tells you to.

If you miss a dose, take it as soon as you remember. If it is more than 8 hours after the missed dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.