Skip to main content
PlainMeds

What the label lists and what reports show

Nirmatrelvir and ritonavir side effects

Nirmatrelvir and ritonavir's FDA label: “Most common adverse reactions (incidence ≥1% and greater incidence than in the placebo group) are dysgeusia and diarrhea.” FAERS holds 53,820 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is disease recurrence (20,103 reports).

  • No generic listed
  • Boxed warning

Check it at the source: the nirmatrelvir and ritonavir FDA label on DailyMed (effective February 19, 2026, Pfizer Laboratories Div Pfizer Inc); the FDA FAERS public dashboard.

What does the patient leaflet say about side effects?

From the patient leaflet: What are the possible side effects of PAXLOVID?

PAXLOVID may cause serious side effects, including: • Allergic reactions, including severe allergic reactions (anaphylaxis) have happened during treatment with PAXLOVID. Stop taking PAXLOVID and get medical help right away if you get any of the following symptoms of an allergic reaction: o skin rash, hives, blisters or peeling skin o painful sores or ulcers in the mouth, nose, throat or genital area o swelling of the mouth, lips, tongue or face o trouble swallowing or breathing o throat tightness o hoarseness • Liver problems. […]

Source: FDA drug label, Pfizer Laboratories Div Pfizer Inc, effective February 19, 2026 (SPL set 8a99d6d6-fd9e-45bb-b1bf-48c7f761232a), via openFDA; the full label on DailyMed

What does the label list?

From the label: adverse reactions

Most common adverse reactions (incidence ≥1% and greater incidence than in the placebo group) are dysgeusia and diarrhea.

From the label: adverse reactions, continued

The following clinically significant adverse reactions are described elsewhere in the labeling: • Hypersensitivity reactions [see Warnings and Precautions (5.2) ] Most common adverse reactions (incidence ≥1% and greater incidence than in the placebo group) are dysgeusia and diarrhea. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Pfizer Inc. at 1-800-438-1985 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The safety of PAXLOVID is based on two Phase 2/3 randomized, placebo-controlled trials in symptomatic adult subjects 18 years of age and older with a laboratory confirmed diagnosis of SARS-CoV-2 infection. Subjects in both studies received PAXLOVID (nirmatrelvir/ritonavir 300 mg/100 mg) or placebo every 12 hours for 5 days for the treatment of mild-to-moderate COVID-19 within 5 days of symptom onset [see Clinical Studies (14) ]: • Trial C4671005 (EPIC-HR) enrolled subjects who were at high risk for progression to severe disease. …

Source: FDA drug label, Pfizer Laboratories Div Pfizer Inc, effective February 19, 2026 (SPL set 8a99d6d6-fd9e-45bb-b1bf-48c7f761232a), via openFDA; the full label on DailyMed

What do FAERS reports show?

53,820 reports list nirmatrelvir and ritonavir among the medicines taken, each a report of something that happened, not proof the medicine caused it; 557 are coded as a death and 3,145 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Reports rose sharply in 2022 (27,027, against a median of 16 a year): FAERS counts follow reporting, which news, litigation and label changes can drive, not how often a reaction happens. Of the 19 reactions below, 6 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.

Reports received each year

The 25 most reported reactions

  • Covid-19 (a use or a product term, not a reaction)22,815
  • Disease Recurrence20,103
  • Dysgeusia (named in the label)7,348
  • Diarrhoea (named in the label)4,027
  • Nausea (named in the label)2,636
  • Headache (named in the label)2,178
  • Cough2,048
  • Fatigue2,014
  • Incorrect Dose Administered (a use or a product term, not a reaction)1,717
  • Vomiting (named in the label)1,408
  • Malaise (named in the label)1,375
  • Nasal Congestion1,367
  • Off Label Use (a use or a product term, not a reaction)1,323
  • Drug Interaction (a use or a product term, not a reaction)1,299
  • Pyrexia1,255
  • Oropharyngeal Pain1,248
  • Dizziness1,200
  • Rhinorrhoea1,090
  • Therapeutic Product Effect Incomplete (a use or a product term, not a reaction)1,080
  • Pain1,065
  • Taste Disorder1,045
  • Symptom Recurrence994
  • Feeling Abnormal968
  • Product Prescribing Error (a use or a product term, not a reaction)968
  • Insomnia869

Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms

What next?

Nirmatrelvir and ritonavir: the full record
label, generics, price, shortages, recalls
Side effects hub
the most reported medicines and reactions