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Nirmatrelvir / ritonavir Side Effects

Medically reviewed by Last updated on Jan 24, 2024.

Applies to nirmatrelvir / ritonavir: oral tablet.


Oral route (Kit; Tablet)

Warning: Significant Drug Interactions with Nirmatrelvir/Ritonavir KitNirmatrelvir / ritonavir kit includes ritonavir, a strong CYP3A inhibitor, which may lead to greater exposure of certain concomitant medications, resulting in potentially severe, life-threatening, or fatal events.Prior to prescribing nirmatrelvir / ritonavir kit: 1) Review all medications taken by the patient to assess potential drug-drug interactions with a strong CYP3A inhibitor like nirmatrelvir / ritonavir kit and 2) Determine if concomitant medications require a dose adjustment, interruption, and/or additional monitoring.Consider the benefit of nirmatrelvir / ritonavir kit treatment in reducing hospitalization and death, and whether the risk of potential drug-drug interactions for an individual patient can be appropriately managed.

Serious side effects

Along with its needed effects, nirmatrelvir / ritonavir may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking nirmatrelvir / ritonavir:

Less common

Incidence not known

Other side effects

Some side effects of nirmatrelvir / ritonavir may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Less common

For Healthcare Professionals

Applies to nirmatrelvir / ritonavir: oral tablet.


Common (1% to 10%): Hypertension[Ref]


Postmarketing reports: Toxic epidermal necrolysis, Stevens-Johnson syndrome


Common (1% to 10%): Diarrhea, vomiting

Postmarketing reports: Abdominal pain, nausea[Ref]


Postmarketing reports: Hypersensitivity reactions, anaphylaxis[Ref]


Common (1% to 10%): Myalgia[Ref]

Nervous system

Common (1% to 10%): Dysgeusia, headache[Ref]


Postmarketing reports: Malaise[Ref]

Frequently asked questions


1. Product Information. Paxlovid (nirmatrelvir-ritonavir). Pfizer Canada ULC. 2022.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.