PAXLOVID 8 Adverse Reactions

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8.2 Clinical Trial Adverse Reactions

Clinical trials are conducted under very specific conditions. The adverse reaction rates observed in the clinical trials; therefore, may not reflect the rates observed in practice and should not be compared to the rates in the clinical trials of another drug. Adverse reaction information from clinical trials may be useful for identifying and approximating rates of adverse drug reactions in real-world use.

The safety of PAXLOVID is based on data from Study C4671005 (EPIC-HR), a Phase 2/3 randomized, placebo-controlled trial in non hospitalized adult subjects with a laboratory confirmed diagnosis of SARS-CoV-2 infection (see 14 CLINICAL TRIALS). A total of 2,224 symptomatic adult subjects 18 years of age and older who are at high risk of developing severe COVID-19 illness received at least one dose of either PAXLOVID (n=1,109) or placebo (n=1,115). Adverse events were those reported while subjects were on study medication and through Day 34 after initiating study treatment. PAXLOVID [300 mg nirmatrelvir (two 150 mg tablets) with 100 mg ritonavir] or matching placebo were to be taken twice daily for 5 days.

Adverse events (all grades regardless of causality) in the PAXLOVID group (≥1%) that occurred at a greater frequency (≥5 subject difference) than in the placebo group were dysgeusia (6% and <1%, respectively), diarrhea (3% and 2%), hypertension (1% and <1%), and myalgia (1% and <1%).

The proportions of subjects who discontinued treatment due to an adverse event were 2% in the PAXLOVID group and 4% in the placebo group.

Table 3. Clinical Trial Adverse Reactions
Adverse events occurring at a ≥1% frequency in the PAXLOVID group and at a greater frequency than in the placebo group.

n = 1109

n = 1115 (%)

Nervous system disorders














8.5 Post-Market Adverse Reactions

The following adverse reactions have been identified during post-authorization use of PAXLOVID. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

[Module 2.5, Clinical Overview, PAXLOVID™ (nirmatrelvir tablets; ritonavir tablets) UPDATES TO CORE DATA SHEET (CDS) VERSION 7.0, 26 SEPTEMBER 2022]

  • Immune System Disorders: Anaphylaxis, Hypersensitivity
  • Vascular Disorders: Hypertension
  • Gastrointestinal Disorders: Abdominal Pain, Nausea
  • General Disorders and Administration Site Conditions: Malaise