Prescription medication · Antiviral (Protease Inhibitor Combination)

nirmatrelvir/ritonavir

Also sold as Paxlovid. Paxlovid treats mild to moderate COVID-19 in adults.

Data updated 2026-05-15

66,080
FDA reports
86
InteractionsMany interactions
$69.72
Brand price (NADAC)

What the data shows

nirmatrelvir/ritonavir (Paxlovid) is a prescription Antiviral (Protease Inhibitor Combination), with 66,080 FDA adverse-event reports on file, with 86 documented drug interactions.

Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.

nirmatrelvir/ritonavir (Paxlovid) is a prescription Antiviral (Protease Inhibitor Combination). Paxlovid treats mild to moderate COVID-19 in adults.

Paxlovid is a medicine used to treat mild to moderate COVID-19 in adults. It helps prevent severe illness, hospitalization, or death in people at high risk.

Verify with FDA → · CMS NADAC pricing →

Drug Pricing (NADAC)

Brand Price

$69.72/unit

Generic Available

No

PFIZER

Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →

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What it does

Paxlovid treats mild to moderate COVID-19 in adults.

Common side effects

Change in taste, Diarrhea

Key warnings

Paxlovid can interact with many other medicines, causing serious or life-threatening problems.

The sections below are summarized in plain English from nirmatrelvir/ritonavir's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.

How It Works

Paxlovid contains two medicines, nirmatrelvir and ritonavir. Nirmatrelvir stops the virus from multiplying in your body. Ritonavir helps nirmatrelvir stay in your body longer so it can work better.

Side Effects (from patient reports)

Based on 66,080 FDA adverse event reports.

Most-reported reactions

Adverse reactions in FAERS for nirmatrelvir/ritonavir, by number of reports

reports

What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.

Source FDA Adverse Event Reporting System (FAERS)

Serious Warnings

Paxlovid can interact with many other medicines, causing serious or life-threatening problems. Before taking Paxlovid, tell your doctor about all the medicines you take. Your doctor may need to adjust the dose of your other medicines or monitor you more closely.

Known Drug Interactions

major simvastatin

HMG-CoA reductase inhibitors lovastatin, simvastatin ↑ lovastatin ↑ simvastatin Co-administration contraindicated due to potential for myopathy including rhabdomyolysis [see Contraindications (4) ] . If treatment with PAXLOVID is considered medically necessary, discontinue use of lovastatin and simvastatin at least 12 hours prior to initiation of PAXLOVID, during the 5 days of PAXLOVID treatment, and for 5 days after completing PAXLOVID.

Mechanism: This medicine stops your body from breaking down simvastatin, which can lead to high levels that cause serious muscle damage.

major lovastatin

HMG-CoA reductase inhibitors lovastatin, simvastatin ↑ lovastatin ↑ simvastatin Co-administration contraindicated due to potential for myopathy including rhabdomyolysis [see Contraindications (4) ] . If treatment with PAXLOVID is considered medically necessary, discontinue use of lovastatin and simvastatin at least 12 hours prior to initiation of PAXLOVID, during the 5 days of PAXLOVID treatment, and for 5 days after completing PAXLOVID.

Mechanism: This medicine blocks the way your body processes lovastatin, which can cause the drug to reach dangerous levels and hurt your muscles.

major sildenafil

Pulmonary hypertension agents (PDE5 inhibitors) sildenafil (Revatio ® ) ↑ sildenafil Co-administration of sildenafil with PAXLOVID is contraindicated for use in pulmonary hypertension due to the potential for sildenafil associated adverse events, including visual abnormalities hypotension, prolonged erection, and syncope [see Contraindications (4) ] . sildenafil, tadalafil, vardenafil ↑ sildenafil ↑ tadalafil ↑ vardenafil Dosage adjustment is recommended for use of sildenafil, tadalafil or vardenafil with PAXLOVID when used for erectile dysfunction.

Mechanism: This combination makes sildenafil stay in your body longer and at higher levels, which can cause your blood pressure to drop too low.

major carbamazepine

Anticonvulsants carbamazepine , phenobarbital, primidone, phenytoin ↓ nirmatrelvir/ritonavir Co-administration contraindicated due to potential loss of virologic response and possible resistance [see Contraindications (4) ] .

Mechanism: Carbamazepine makes your body get rid of the antiviral medicine too quickly, which prevents it from working against the virus.

major rifampin

Antimycobacterial rifampin, rifapentine ↓ nirmatrelvir/ritonavir Co-administration contraindicated due to potential loss of virologic response and possible resistance.

Mechanism: Rifampin causes the body to break down nirmatrelvir/ritonavir too quickly, which lowers the amount of medicine in your blood. This can make the treatment less effective and may lead to the virus becoming resistant.

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This is a plain-language summary of FDA-label interaction records and does not provide individual medication-combination directions.

Common Questions

How long do I take Paxlovid?
You will take Paxlovid for 5 days.
Can I take Paxlovid if I have kidney problems?
Your doctor may need to adjust your dose if you have kidney problems.
Can I take Paxlovid if I have liver problems?
Paxlovid is not recommended if you have severe liver problems.
What should I do if I feel sick while taking Paxlovid?
Contact your doctor if you feel sick or have any new symptoms while taking Paxlovid.
Can Paxlovid prevent me from spreading COVID-19 to others?
Completing the full 5-day treatment and isolating yourself helps to stop the spread of the virus.
What if my COVID-19 symptoms get worse after starting Paxlovid?
Tell your doctor immediately if your symptoms worsen or if you need to be hospitalized.
Can I take Paxlovid to prevent COVID-19?
No, Paxlovid is not approved to prevent COVID-19.
Will Paxlovid interact with my other medications?
Paxlovid can interact with many medications. Review all your medications with your doctor before starting Paxlovid.
What do the Paxlovid pills look like?
The nirmatrelvir tablets are pink and oval-shaped. The ritonavir tablets are white and capsule-shaped or ovaloid.
How should I dispose of unused Paxlovid?
Ask your pharmacist about the best way to dispose of unused Paxlovid. You can also check for local drug take-back programs.
What are the common side effects of nirmatrelvir/ritonavir?
The registry lists Change in taste, Diarrhea among the most-reported FAERS reaction terms for nirmatrelvir/ritonavir. The compiled record contains 66,080 FDA adverse-event reports. These counts are not an individual symptom assessment.
Does nirmatrelvir/ritonavir interact with other medications?
The registry has 86 documented interaction rows for nirmatrelvir/ritonavir. Notable source-record pairings include simvastatin, lovastatin, sildenafil. These rows are not a complete medication review.
What drug class is nirmatrelvir/ritonavir?
nirmatrelvir/ritonavir belongs to the Antiviral (Protease Inhibitor Combination) drug class. It requires a prescription (Rx). Paxlovid treats mild to moderate COVID-19 in adults.
What pregnancy or breastfeeding source fields are listed for nirmatrelvir/ritonavir?
The FDA label for nirmatrelvir/ritonavir contains product-specific pregnancy or breastfeeding language. PlainMeds does not apply that source text to an individual.

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What the FDA Data Shows for nirmatrelvir/ritonavir

The FDA label for nirmatrelvir/ritonavir (sold under brand names such as Paxlovid) classifies it as a prescription-only medication in the Antiviral (Protease Inhibitor Combination) class. Paxlovid treats mild to moderate COVID-19 in adults. Official labeling lists 2 commonly reported side effects, including Change in taste, Diarrhea.

Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 66,080 voluntary reports. The database also lists 86 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated major severity. NADAC pricing from CMS.

Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information are separate source-record fields. This page is a public FDA/CMS registry and does not provide medical, treatment, substitution, or medication-change directions.

Data Sources

Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).

FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. This registry does not provide medication decisions.

Last updated: January 5, 2026

PlainMeds is rendered directly from FDA openFDA/FAERS extracts, DailyMed labels, and CMS drug-pricing files, no number is typed in by an editor. FAERS counts, recalls, shortages, and price figures on this page are queried live from those federal extracts. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-05-15. Primary sources: openFDA / FAERS, DailyMed and CMS Part B ASP.

Read our methodology - how this data is sourced, computed, and verified.

Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled from the source snapshot dated . See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a data issue.

All federal data sources used on this page