Nirmatrelvir and Naloxegol: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Naloxegol
Nirmatrelvir
No brand names on record
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Increased naloxegol exposure and increased risk of opioid withdrawal symptoms
Interaction Deep Dive
Concomitant use of naloxegol and nirmatrelvir/ritonavir is contraindicated, as coadministration may increase naloxegol exposure and increase the risk of opioid withdrawal symptoms2 such as hyperhidrosis, chills, diarrhea, abdominal pain, anxiety, irritability, and yawning 1. Withhold naloxegol during nirmatrelvir/ritonavir treatment and for 2 to 3 days (or longer in certain cases such as advanced patient age) after discontinuation if possible. Consider treatment with an alternative concomitant drug or COVID-19 treatment if temporarily withholding naloxegol is not clinically reasonable 3.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated naloxegol metabolism
Common questions
Can I take Nirmatrelvir and Naloxegol together?
Increased naloxegol exposure and increased risk of opioid withdrawal symptoms Always confirm with your pharmacist or prescriber before making any change.
How serious is the Nirmatrelvir and Naloxegol interaction?
It is rated contraindicated. These should generally not be used together.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Nirmatrelvir or Naloxegol need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (3)
- Product Information: MOVANTIK(TM) oral tablets, naloxegol oral tablets. AstraZeneca (per manufacturer), Wilmington, DE, 2014. DailyMed
- Product Information: PAXLOVID(TM) oral tablets, nirmatrelvir oral tablets, ritonavir oral tablets. Pfizer Labs (per FDA), New York, NY, 2023. DailyMed
- COVID-19 Treatment Guidelines Panel: Coronavirus disease 2019 (COVID-19) treatment guidelines. National Institutes of Health (NIH). Bethesda, MD. 2023.
Keep reading about Naloxegol
Keep reading about Nirmatrelvir
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