Curious about clinical trials?

Access the latest treatments and medications. unavailable elsewhere - entirely free of charge. We make it easy to take part.

Boxed warning:¹

Paxlovid has a boxed warning. A wide range of drugs are known to interact negatively with Paxlovid. For this reason, doctors must consider the risk of interactions when prescribing the drug. Provide your doctor with a complete list of all medications, vitamins, herbs, and supplements you take regularly or occasionally. Your doctor may need to adjust the dose, pause your treatment while you undergo Paxlovid therapy, or monitor you more closely.

Particularly, the ritonavir component of Paxlovid, a protease inhibitor, may increase the concentration of other medications within your body, potentially leading to severe adverse effects. In some cases, these effects may be fatal.

What is Paxlovid?

Paxlovid is a drug used to treat coronavirus disease 2019 (COVID-19). It's an oral antiviral medication recommended for high-risk patients in the first few days of the infection to reduce their risk of hospitalization and death. Paxlovid is a combination of the generic medications nirmatrelvir and ritonavir.

Nirmatrelvir is a protease inhibitor that stops viral replication in the early stages of COVID-19 to prevent progression to full-blown illness. Nirmatrelvir is co-administered with ritonavir, another protease inhibitor, to slow its breakdown in the liver and ensure it remains active in the body at higher concentrations for longer, giving the drug an infection-fighting boost.²

The US Food and Drug Administration (FDA) gave Paxlovid full approval in May 2023 after initially granting an emergency use authorization (EUA) for the treatment of COVID-19 infection with certain guidelines in December 2021.³ ⁴

In the clinical trial that supported the EUA, the investigators reported an 89% reduction in the risk of progression to severe disease leading to hospitalization and death for patients given Paxlovid compared to those who took a placebo.⁵

What is Paxlovid used to treat?

Paxlovid is FDA-approved for the treatment of COVID-19 in adults with mild-to-moderate COVID-19 who are not hospitalized at the time of diagnosis but face a high risk of severe disease and hospitalization.⁶

Currently, Paxlovid manufactured and distributed under the EUA remains available to allow continued access for patients who are not eligible under the full authorization, including children aged 12 to 18 years who meet the previous guidelines. Under the EUA, patients must fit the following criteria:

  • A current diagnosis of COVID-19 (note: a positive test is no longer required)⁷

  • 12 years of age and older

  • Weight at least 88 pounds (40kg)

  • High risk for progression to severe disease

Limitations have been delineated as follows:

  • Patients already hospitalized for severe COVID-19 disease should not be started on Paxlovid

  • Paxlovid should not be used for those needing pre- or post-exposure therapy for the prevention of COVID-19

  • Use for longer than five days is not authorized

Paxlovid protects people with COVID-19 who face a high risk of developing severe disease. It does not prevent these individuals from developing COVID-19 symptoms altogether, nor does it prevent infection with the virus after exposure.

Who is eligible to take Paxlovid?

Only patients at high risk for progressing to severe disease are authorized to receive Paxlovid.

You are classified in the high-risk category if you are over 50 years old (with a substantially increased risk for those 65 and above) or have any of the following health conditions:⁸ ⁹

  • Diabetes (types 1 and 2)

  • Certain types of cancer (e.g., hematologic malignancies)

  • Various autoimmune diseases

  • Heart conditions (e.g., heart failure, coronary artery disease, or cardiomyopathy)

  • Chronic kidney disease (on dialysis)

  • Chronic liver diseases

    • Cirrhosis

    • Non-alcohol-related fatty liver disease

    • Alcohol-associated liver disease

    • Autoimmune hepatitis

  • Primary immunodeficiency

  • Taking corticosteroids or other immunosuppressant medications

  • Asthma

  • Chronic lung disease

    • Cystic fibrosis

    • Bronchiectasis

    • Chronic obstructive pulmonary disease (COPD)

    • Interstitial lung disease

    • Pulmonary embolism

    • Pulmonary hypertension

  • Cerebrovascular disease (e.g., history of stroke or brain aneurysm)

  • HIV infection

  • Neurological conditions such as dementia, neuromuscular disorders, and neurodevelopmental disorders (see complete list here)¹⁰

  • Certain disabilities or genetic conditions, such as Trisomy 21

  • Pregnancy or recent pregnancy

  • Current or past smoking

  • Transplant history

  • Use of steroids or other immunosuppressant drugs 

  • Tuberculosis

  • Schizophrenia or mood disorders, including depression

  • Substance use disorder (suggestive higher risk)

  • Sickle cell disease (suggestive higher risk)

  • Obesity (BMI ≥ 30kg/m²) with a suggestive higher risk for those in the overweight category (BMI ≥ 25kg/m²)

  • Sedentary lifestyle

  • Children with underlying health conditions

  • Unvaccinated or not up-to-date COVID-19 vaccination status¹¹

Who should not take Paxlovid?

People who do not meet the high-risk criteria or are outside of the five-day window for symptoms of COVID-19 infection are not eligible for Paxlovid therapy.

Not everyone who qualifies to take Paxlovid under the above criteria should take the drug. The drug is not authorized for patients hospitalized for COVID-19 infection. Some people may not be able to take Paxlovid for other health reasons.

Inform your prescriber before starting to take this drug if you have any of the following:¹²

  • Liver problems

  • Kidney disease

  • Lactose or galactose intolerance (or malabsorption) or lactase deficiency (nirmatrelvir contains lactose)

  • A serious medical condition

  • HIV infection and are being treated with antiviral medications

  • Are severely allergic to nirmatrelvir, ritonavir, or any of the inactive ingredients

  • Are taking a hormonal form of birth control

  • Are pregnant, trying to become pregnant, or breastfeeding

If any of these apply to you, the FDA recommends discussing your options and specific situation with your doctor.

How do you take Paxlovid?

Paxlovid is available by prescription only. The drug is most effective when taken within five days of developing COVID-19 symptoms. Thus, in July 2022, the FDA extended prescribing privileges to state-licensed pharmacists under the EUA. Pharmacists must have sufficient access to the patient’s recent health records (within the preceding 12 months) or be in contact with their doctor to obtain information on their kidney and liver function. The patient (or their physician) must also provide a current medication list so the pharmacist can check for potential drug interactions.¹³

The drug is available in two different dose packs:

  • A package containing nirmatrelvir 300mg tablets and ritonavir 100mg tablets

  • A package containing nirmatrelvir 150mg tablets and ritonavir 100mg tablets

Regardless of the packaging, the two medications are taken together twice daily for five days. Most people will take 300mg of nirmatrelvir and 100mg of ritonavir at each dose. However, doctors may prescribe a lower dose for people with certain conditions.

You can take Paxlovid with or without food. Ensure you swallow the tablets whole; do not chew, crush, or break them. Complete the five-day course even if you start feeling better and your symptoms improve.

Seeing results

Paxlovid works fairly quickly. Its active ingredients, nirmatrelvir and ritonavir, reach peak concentrations in the blood within approximately three and four hours, respectively.¹⁴

While Paxlovid starts working soon after you take it, you may not feel better right away. The drug is intended to prevent the progression from mild or moderate symptoms to severe illness. You may begin to feel better within a few days of starting treatment, but it is important to continue taking Paxlovid until the end of your prescribed treatment period (five days).

Potential side effects of Paxlovid

Paxlovid is currently the most effective oral antiviral available for reducing the risk of severe COVID-19. Like all drugs, Paxlovid is likely to cause side effects for some people.¹⁵

Several common side effects have been reported by patients, including the following:¹⁶

  • Muscle aches

  • High blood pressure

  • Diarrhea

  • Altered sense of taste (dysgeusia)

  • Feeling generally unwell

  • Nausea, vomiting

  • Abdominal pain

  • Headache

The most serious known adverse effects of Paxlovid include the following:¹⁷

  • Resistance to HIV antiviral medicines

  • High blood pressure¹⁸

  • Diagnosed liver conditions or signs of undiagnosed liver problems, including any of the following:

    • Loss of appetite

    • Abdominal pain

    • Pale-colored stool

    • Dark-colored urine

    • Jaundice (yellowing of the skin and the whites of your eyes)

  • Allergic reactions (see Allergy Information below)

  • Decreased white blood cell count¹⁹

Note that this is not an exhaustive list of all the possible side effects of Paxlovid. If you notice anything unusual while taking Paxlovid, call your prescriber.


Only take Paxlovid as recommended by your prescriber. Overdoses can result in liver toxicity, with symptoms like jaundice, nausea, and fatigue. If you believe you have taken too much Paxlovid, call your doctor or the National Poison Control Center helpline immediately, or go to the nearest emergency department.²⁰

Allergy information

Paxlovid can cause allergic reactions and, rarely, a serious allergic reaction (anaphylaxis).²¹

Possible symptoms include the following: 

  • Swelling of the face, lips, tongue, or throat (causing difficulty swallowing or hoarseness)

  • Difficulty breathing, wheezing

  • Rash, hives, itching

  • Vomiting

  • Loss of consciousness

Stop taking Paxlovid and call your healthcare provider if you experience any symptoms of an allergic reaction. If the effects are severe or life-threatening, call 911.

Long-term use of Paxlovid

A full course of Paxlovid lasts five days. There is currently no sufficient evidence to support the safety or efficacy of the drug when used beyond the standard treatment period.

Paxlovid and pregnancy

There is limited knowledge about treating expectant or breastfeeding mothers with Paxlovid, as these groups have been excluded from the clinical trials. However, pregnancy is considered a risk factor for serious COVID-19 disease and progression, and the benefit of taking the drug may outweigh the potential risks of the treatment. If you are pregnant or breastfeeding, the FDA recommends that you speak with your doctor about your unique situation and the risks that pertain to you.²² ²³

Missed doses

If you miss a dose of Paxlovid within eight hours of the time you usually take it, take it as soon as possible. If it's been more than eight hours, skip the missed dose and take the next one at its regularly scheduled time. Don’t double your dose to make up for a missed one.²⁴

Drug interactions

Certain medications can have unsafe interactions with Paxlovid. Tell your doctor about other drugs you're taking, including prescription and over-the-counter (OTC) medications, vitamins, and herbal supplements. Paxlovid is contraindicated in people taking drugs in the following categories:²⁵

(Drugs marked with an asterisk * may be withheld under medical supervision for a few days during Paxlovid treatment.)

  • Antibiotics, including rifampin (taken within the preceding two weeks), clarithromycin (Biaxin), and erythromycin*

  • Antivirals like glecaprevir/pibrentasvir (Mavyret), darunavir (Prezista), tipranavir (Aptivus), and others

  • Asthma medications, such as salmeterol* (Serevent)

  • Birth control pills containing ethinyl estradiol*

  • Blood pressure treatments, including aliskiren* (Tekturna), and calcium channel blockers like amlodipine (Norvasc), nicardipine (Cardene), and verapamil (Calan)

  • Blood thinners and antiplatelet drugs like clopidogrel (Plavix), rivaroxaban* (Xarelto), ticagrelor* (Brilinta), and vorapaxar* (Zontivity)

  • Chemotherapy drugs, including apalutamide (Erleada) and everolimus* (Afinitor)

  • Drugs prescribed for chest pain, such as ranolazine* (Ranexa)

  • Cholesterol-lowering drugs, including atorvastatin* (Lipitor), lomitapide* (Juxtapid), lovastatin* (Mevacor), rosuvastatin* (Crestor), and simvastatin* (Zocor)

  • The cystic fibrosis drug lumacaftor/ivacaftor (sold as a combination treatment under the brand name Orkambi)

  • Medications for erectile dysfunction, including avanafil* (Stendra), sildenafil (Viagra), and others

  • The gout treatment colchicine* (Colcrys) 

  • Heart rhythm medications, such as amiodarone (Pacerone), dronedarone (Multaq), disopyramide (Norpace), flecainide (Tambocor), and propafenone (Rythmol)

  • Certain herbal products, such as St. John’s wort

  • Immune system suppressants like voclosporin (Lupkynis), sirolimus* (Rapamune), and tacrolimus* (Prograf)

  • The kidney disease treatment tolvaptan (Jynarque)

  • Migraine medicines, such as ergotamine (Cafergot), dihydroergotamine (Migranal), eletriptan* (Relpax), rimegepant* (Nurtec), and ubrogepant* (Ubrelvy)

  • Prostate medicines like alfuzosin* (Uroxatral) and silodosin* (Rapaflo)

  • Pulmonary hypertension medications, including sildenafil (Revatio), bosentan (Tracleer), and tadalafil (Adcirca)

  • Psychiatric drugs, such as aripiprazole (Abilify), lurasidone (Latuda), pimozide (Orap), and clozapine (Clozaril)

  • Sedatives like midazolam (Versed)* and diazepam (Valium) 

  • Seizure medications, such as carbamazepine (Tegretol), phenobarbital (Luminal), primidone (Mysoline), and phenytoin (Dilantin)

  • Sleeping pills, including suvorexant* (Belsomra), zolpidem (Ambien), and triazolam* (Halcion)

  • Steroid medications, such as budesonide, dexamethasone, and methylprednisolone

  • Other medications, including finerenone* (Kerendia), flibanserin* (Addyi), and naloxegol* (Movantik)

This is not a complete list of drug interactions for Paxlovid. Some of your prescription medications may need to be dose-adjusted while you are taking the drug. Your healthcare prescriber can tell you if it is safe to take Paxlovid with other medicines. Notably, Paxlovid may affect how birth control pills work. You can ask your doctor or pharmacist for a list of drugs known to interact with Paxlovid.²⁶

Can I drink alcohol while taking Paxlovid?

It's not known if alcohol affects the progression of COVID-19 infection or the effectiveness of Paxlovid therapy. However, combining medications with alcohol often leads to unpredictable and unwanted consequences, and patients with infections should use caution.²⁷

Stopping Paxlovid

Stop taking Paxlovid after completing the five-day course and not before. Stopping the medication too early may allow the virus to continue reproducing, increasing the risk of the infection progressing to severe COVID-19.

Drug approval history

  • 2021: Paxlovid was approved under the EUA.²⁸

  • 2023: Paxlovid earned full FDA approval.²⁹ ³⁰

Tips for taking Paxlovid

If taken correctly, Paxlovid can effectively stop the progression of COVID-19 to severe disease and hospitalization in at-risk individuals. Here are a few tips for taking Paxlovid for those eligible for the drug:

  • Start taking Paxlovid within the first five days of the onset of COVID-19 symptoms to effectively prevent progression to severe illness. Make sure to take the medication for the full five days, even if you are feeling better.

  • Take Paxlovid as directed by your healthcare professional or the prescription label. Do not give your medication to another person, even if they have the same symptoms, because it might harm them.

  • If your tablets come in a blister pack, do not remove them until you are ready to take your dose. Store them in a dry place at room temperature.

  • Try to take your medication at roughly the same times in the morning and evening.

  • Let your prescriber know if you start other new medicines while taking Paxlovid.

  • Do not stop taking the medication without talking to your doctor, even if you feel better. 

  • This guide was last updated June 2023 (please check with your doctor or local health authority for the most up-to-the-minute recommendations).

Paxlovid FAQs

Is Paxlovid safe to take?

Paxlovid is safe for most people. However, it’s not suitable for everyone. Patients with certain medical conditions, such as kidney disease, may not be able to take it and will require an alternative therapy. Others on medications known to interact negatively with Paxlovid might need to discontinue them briefly or avoid taking Paxlovid. (See Who should not take Paxlovid? for more information.)

Your prescriber will assess your unique situation to decide if Paxlovid is appropriate for you.

Can I take Tylenol and Paxlovid?

There are no known interactions between Tylenol and Paxlovid. However, you must discuss all medications with your doctor, as many treatments (including those available without a prescription) contain more than one active ingredient.

  1. Paxlovid Label | US FDA

  2. Nirmatrelvir-Ritonavir | NIH StatPearls

  3. Paxlovid Label | US FDA 

  4. Fact Sheet For Healthcare Providers: Emergency Use Authorization for Paxlovid | US FDA 

  5. Oral Nirmatrelvir for High-Risk, Nonhospitalized Adults with Covid-19 | The New England Journal of Medicine 

  6. FDA Approves First Oral Antiviral for Treatment of COVID-19 in Adults | US FDA

  7. Fact Sheet For Healthcare Providers: Emergency Use Authorization for Paxlovid | US FDA 

  8. Underlying Medical Conditions Associated with Higher Risk for Severe COVID-19: Information for Healthcare Professionals | CDC 

  9. Interim Clinical Considerations for COVID-19 Treatment in Outpatients | CDC 

  10. Underlying Medical Conditions Associated with Higher Risk for Severe COVID-19: Information for Healthcare Professionals | CDC 

  11. Paxlovid (nirmatrelvir co-packaged with ritonavir) | US Department of Health and Human Services 

  12. Paxlovid Label | US FDA

  13. Fact Sheet For Healthcare Providers: Emergency Use Authorization for Paxlovid | US FDA 

  14. Nirmatrelvir/Ritonavir (Rx) | Medscape

  15. Effectiveness of Paxlovid in Reducing Severe Coronavirus Disease 2019 and Mortality in High-Risk Patients | Clinical Infectious Diseases 

  16. Nirmatrelvir/Ritonavir (Rx) | Medscape 

  17. Paxlovid: Safety, Side Effects, & Drug Interactions | Pfizer 

  18. Paxlovid Label | US FDA 

  19. Oral Nirmatrelvir for High-Risk, Nonhospitalized Adults with Covid-19 | The New England Journal of Medicine

  20. Nirmatrelvir-Ritonavir | NIH StatPearls 

  21. Paxlovid Label | US FDA

  22. Paxlovid (Nirmatrelvir and Ritonavir) Use in Pregnant and Lactating Woman: Current Evidence and Practice Guidelines—A Scoping Review | Vaccines 

  23. Fact Sheet for Patients, Parents, and Caregivers: Emergency Use Authorization (EUA) of Paxlovid for Coronavirus Disease 2019 (COVID-19) | US FDA

  24. Nirmatrelvir/Ritonavir (Rx) | Medscape 

  25. Drug-Drug Interactions Between Ritonavir-Boosted Nirmatrelvir (Paxlovid) and Concomitant Medications | NIH 

  26. Fact Sheet for Patients, Parents, and Caregivers: Emergency Use Authorization (EUA) of Paxlovid for Coronavirus Disease 2019 (COVID-19) | US FDA

  27. Interactions Between Alcohol and the Antiretroviral Medications Ritonavir or Efavirenz | Journal of Addiction Medicine 

  28. Fact Sheet For Healthcare Providers: Emergency Use Authorization for Paxlovid | US FDA 

  29. FDA Approves First Oral Antiviral for Treatment of COVID-19 in Adults | US FDA 

  30. Paxlovid Label | US FDA

Curious about clinical trials?

Access the latest treatments and medications. unavailable elsewhere - entirely free of charge. We make it easy to take part.


Here at HealthMatch, we’ve done our best to ensure that the information provided in this article is helpful, up to date, and, most importantly, accurate.

However, we can’t replace the one-to-one advice of a qualified medical practitioner or outline all of the possible risks associated with this particular drug and your circumstances.

It is therefore important for you to note that the information contained in this article does not constitute professional medical or healthcare advice, diagnosis or recommendation of treatment and is not intended to, nor should be used to, replace professional medical advice. This article may not always be up to date and is not exhaustive of all of the risks and considerations relevant to this particular drug. In no circumstances should this article be relied upon without independent consideration and confirmation by a qualified medical practitioner.

Your doctor will be able to explain all possible uses, dosages, precautions, interactions with other drugs, and other potential adverse effects, and you should always talk to them about any kind of medication you are taking, thinking about taking or wanting to stop taking.

Curious about clinical trials?

Access the latest treatments and medications. unavailable elsewhere - entirely free of charge. We make it easy to take part.