What is Paxlovid: Uses, Warnings & Interactions

Updated May 14, 2025  •  Published Jan 27, 2022

Paxlovid is a brand-name antiviral medication granted emergency authorization by the FDA to treat coronavirus disease 2019 (COVID-19). Paxlovid does not cure the infection but reduces the risk of hospitalization and death in at-risk patients. There are two drugs in Paxlovid, each taken as separate tablets. Nirmatrelvir prevents the COVID-19 virus from making new viruses. Ritonavir is also an antiviral medication, but it’s used in Paxlovid to prevent the body from breaking down nirmatrelvir. People prescribed Paxlovid will take two tablets—one nirmatrelvir tablet and one ritonavir tablet—twice daily for five days.

Paxlovid overview

BRAND NAMES:

  • Paxlovid

Generic Names:

  • Nirmatrelvir/ritonavir, ritonavir-boosted nirmatrelvir

Uses:

  • Reduces the risk of hospitalization and death in at-risk patients with COVID-19

Therapeutic Classes:

  • Antiviral

Forms:

  • Tablet

How it’s taken:

  • By mouth

What is Paxlovid used for?

Paxlovid treats mild-to-moderate COVID-19 in adults and children older than 12 years of age and weighing more than 88 pounds who are at risk of severe infection or complications. Paxlovid does not cure COVID-19 but instead significantly reduces the risk of hospitalization or death.

What form(s) does Paxlovid come in

  • Tablets

    • 300 mg nirmatrelvir/100 mg ritonavir dose pack

    • 150 mg nirmatrelvir/100 mg ritonavir dose pack

What are common Paxlovid doses?

  • For mild to moderate COVID-19 in adults and children 12 years of age and older: Two 150 mg nirmatrelvir tablets and one 100 mg ritonavir tablet taken twice per day, once in the morning and once at night for five days

    • In adults and children with moderate kidney impairment: One 150 mg nirmatrelvir tablet and one 100 mg ritonavir tablet taken twice per day, once in the morning and once at night for five days

Common Paxlovid prescriptions

  • Paxlovid
    2 tablets therapy pack blister

  • Paxlovid
    3 tablets therapy pack blister

  • Paxlovid
    20 tablets therapy pack box

  • Paxlovid
    30 tablets therapy pack box

  • Paxlovid
    4 tablets therapy pack box

  • Paxlovid
    6 tablets therapy pack box

  • Paxlovid
    10 x 150 mg & tablet therapy pack

How to take Paxlovid

  • Take Paxlovid exactly as instructed.

  • Doses are taken once in the morning and once at bedtime.

  • The first dose is taken either in the morning or at bedtime on the day you pick up the dose pack.

  • Paxlovid can be taken with or without food. 

  • Do not remove the tablets from the blister pack until ready to take a dose.

  • Swallow two pink tablets (nirmatrelvir) one after another with a drink of water and immediately swallow one white tablet (ritonavir) with a drink of water.

  • Swallow the tablets whole. Do not break, crush, or chew the tablets.

  • Store Paxlovid tablets in their original carton at room temperature.

What to do if you miss a dose of Paxlovid

  • A missed dose can be taken within eight hours of its scheduled time.

  • If more than eight hours have passed from the time scheduled for the dose, skip the missed dose. Take the next dose at its regular time.

  • Do not take two doses to make up for a missed dose.

Paxlovid contraindications

  • Paxlovid is not safe for everyone.

  • Do not take Paxlovid if you have had an allergic reaction to nirmatrelvir, ritonavir, or other drugs called protease inhibitors.

  • Paxlovid is contraindicated for use with a large number of other drugs and supplements because of the risk of serious or life-threatening problems. The prescriber will need a complete account of all drugs being taken or used.

Paxlovid warnings

  • It is very important that any doctor or other healthcare provider who treats you knows that you are using this medicine. Paxlovid can cause serious and even life-threatening problems in people taking certain drugs.

  • Tell your doctor if you are pregnant, breastfeeding, or have:

    • Kidney problems

    • Liver problems

    • Have an HIV-1 infection

  • Paxlovid can cause serious allergic or drug reactions. Immediately contact a healthcare professional if you experience itching, hives, trouble breathing, or severe skin rash.

  • Talk to the prescriber if symptoms don’t improve after five days of taking Paxlovid.

Paxlovid interactions

  • Ritonavir, one of the active ingredients in Paxlovid, has a large number of significant drug interactions.

  • To avoid potentially hazardous or life-threatening drug interactions, tell the prescribing healthcare provider about all prescription drugs, over-the-counter medications, herbal remedies, and supplements in use before using Paxlovid.

  • Tell other healthcare providers you are taking Paxlovid before they prescribe new medications.

  • Because of the risk of serious or life-threatening drug interactions, the following drugs can never be taken along with Paxlovid. In some cases, Paxlovid is prohibited even if the drug is immediately discontinued. The list of contraindicated drugs is long:

    • Alfuzosin

    • Amiodarone

    • Addyi (flibanserin)

    • Apalutamide

    • Carbamazepine

    • Colchicine

    • Corlanor (ivabradine)

    • Dihydroergotamine

    • Dronedarone

    • Eletriptan

    • Eplerenone

    • Ergotamine

    • Finerenone

    • Flecainide

    • Latuda (lurasidone)

    • Lomitapide

    • Lovastatin

    • Lumacaftor/ivacaftor

    • Lupkynis (voclosporin)

    • Methylergonovine

    • Midazolam (oral)

    • Naloxegol

    • Phenobarbital

    • Phenytoin

    • Pimozide

    • Primidone

    • Propafenone

    • Quinidine

    • Ranolazine

    • Rifampin

    • Rifapentine

    • St. John’s Wort (hypericum perforatum)

    • Revatio (sildenafil) for pulmonary arterial hypertension

    • Silodosin

    • Simvastatin

    • Tolvaptan

    • Triazolam

    • Ubrelvy (ubrogepant)

  • Doctors may need to discontinue, reduce doses, or monitor the following types of medications in people taking Paxlovid:

    • Asthma maintenance treatments

    • Corticosteroids

    • Migraine drugs

    • Narcotic pain relievers

    • Macrolide antibiotics such as erythromycin and clarithromycin

    • Antifungal medications

    • Antiviral medications

    • Blood pressure drugs

    • Statins

    • Heart rhythm medications

    • Pulmonary hypertension treatments

    • Blood thinners

    • Anticancer drugs

    • Antidepressants

    • Antipsychotics

    • Sedatives

    • Anti-seizure medications

    • Drugs that block the immune system

    • Alpha blockers

    • Anticholinergic drugs

  • Paxlovid reduces the effectiveness of birth control pills and other hormonal contraceptives. Women taking Paxlovid should use another form of birth control while taking Paxlovid tablets.

Paxlovid side effects

Serious side effects

Talk to a doctor if you notice any signs or symptoms of a possible serious side effect, including:

  • Yellowing of the skin or eyes, pale stools, dark urine, abdominal pain, itchy skin, decreased appetite

  • Blistering, peeling, red skin rash, mouth sores, genital sores

  • Allergic reaction: Itching, skin rash, hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, throat tightness, trouble breathing

Less serious side effects

  • Changes in taste or bad taste in the mouth

  • Diarrhea

Sources:

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