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Mechanism of Action  Safety & Tolerability

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Search the Interaction Finder 

The Interaction Finder allows you to easily search for drug interactions by active substance name or keywords. 

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Paxlovid contains nirmatrelvir and ritonavir. Ritonavir is administered with nirmatrelvir as a pharmacokinetic enhancer to increase systemic concentrations1

Ritonavir is a widely used treatment with a known profile2,3
  • Ritonavir is used in combination with other antivirals to similarly inhibit drug metabolism2,3

For a list of potential clinically significant drug interactions, including contraindicated drugs, refer to Section 4.3: Contraindications, Section 4.5: Interaction with other medicinal products and other forms of interaction and Table 2: Interaction with other medicinal products and other forms of interaction of the SmPC [here].1

EXPLORE MOREEfficacy & trial design

Discover the efficacy data and trial design of EPIC-HR. 

ButtonLoadingEfficacyLoading Trial design LoadingReferences:
1. PAXLOVID Summary of Product Characteristics.
2. Owen DR, Allerton CMN, Anderson AS, et al. An oral SARS-CoV-2 Mpro inhibitor clinical candidate for the treatment of COVID-19. Science. 2021;374(6575):1586-1593.
3. NORVIR Summary of Product Characteristics. https://www.medicines.ie/medicines/norvir-100mg-film-coated-tablets-33125/spc(accessed July 2025).  Dosing
▼ This medicinal product is subject to additional monitoring. This will allow quick identification of new safety information. Healthcare professionals are asked to report any suspected adverse reactions. See section 4.8 of the SmPC for how to report adverse reactions.

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Further information is available upon request

PP-C1D-IRL-0083. July 2025

Adverse events should be reported.

If you wish to make a medical information inquiry or report an adverse event please contact Pfizer on 1800 633 363 
or email Pfizer at [email protected] or visit www.PfizerMedicalInformation.ie

Report an adverse event to your national reporting system (HPRA Pharmacovigilance)

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