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What does it do?

Nirmatrelvir and ritonavir is used to treat COVID-19. It reduces the chances that you will need hospital treatment.

Before you start

  • Tell your doctor if you have kidney problems.
  • Tell your doctor if you are pregnant, planning to become pregnant, or breastfeeding.

How should you take it?

Take nirmatrelvir and ritonavir regularly as directed with a glass of water. Swallow the tablets whole. You can take them with or without food.
You need to start taking nirmatrelvir and ritonavir within 5 days of getting COVID-19 symptoms.
Keep taking it until the course is finished, even if you start to feel better.

What if you forget a dose?

Take the missed dose as soon as possible and continue as directed.

Can you take other medicines?

Nirmatrelvir and ritonavir can react with many medicines, sometimes with severe results.
Tell your pharmacist or doctor about all medicines or treatments that you may be taking including vitamins, herbal products, or recreational drugs.

What side effects might you notice?

Nirmatrelvir is a new medicine. All the possible side effects are not known at this time.

Side EffectsRecommended action

Changes in taste

Diarrhoea

Tell your doctor if troublesome

If you notice any other effects, discuss them with your doctor or pharmacist.


This leaflet contains important, but not all, information about this medicine.

Prepared by the MyMedicines Committee at Christchurch Hospital, Te Whatu Ora - Waitaha, New Zealand. March 2023

For more general information about this sheet and its contents, see: What does a My Medicines sheet cover?

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About My Medicines

My Medicines Patient Information Leaflets (PILs) contain important, but not all, information about the medicines they describe.

For more information about the sheets, see: What does a My Medicines sheet cover?

My Medicines is developed by a team at Te Whatu Ora – Waitaha. Our team is made up of doctors, pharmacists, and a non-medical person to help us keep to plain language. We also discuss our information with specialist health professionals or groups when needed