Medication Information Leaflet

What is this medication for?

PAXLOVID is an antiviral medication which may be used for treatment of mild-moderate COVID-19 in adults and children (12 years of age and older, and weighing at least 40 kilograms) who are at increased risk of progressing to severe COVID-19. It should be administered within 5 days of symptom onset.   

How should I take/use this medication?

The usual dosage is 300 mg Nirmatrelvir (two 150 mg, pink-coloured tablets) and 100 mg Ritonavir (one 100 mg, white-coloured tablet). Take all three tablets together twice daily for 5 days, with or without food. Complete this 5-day course even if you feel better.

If you have kidney disease, and are considered by your doctor to be suitable for PAXLOVID, you may need a lower dosage (one 150 mg pink coloured tablet of Nirmatrelvir, with one 100 mg white-coloured tablet of Ritonavir, twice daily for 5 days).

PAXLOVID should not be used for longer than 5 consecutive days because the safety and efficacy of use for longer than 5 consecutive days have not been established.

If you do not feel better, or if you feel worse during or after the course of 5 days, you should see your doctor.

PAXLOVID tablets may be split or crushed for administration via a feeding tube or mixed with food or liquid, if necessary. Any suspension or preparation made with crushed PAXLOVID should be consumed/administered immediately.

What should I do if I forget to take/use this medication?

If you miss a dose within 8 hours of the time it is usually taken, take it as soon as possible and take your next dose at the usual time.

If you miss a dose by more than 8 hours, skip the dose and take your next dose at the usual time. Do not take double doses to make up for the missed dose.

What precautions should I take?

Inform your healthcare professional if: 

  • You are allergic to this medication or any of the other ingredients of this medication
  • You are pregnant, planning to become pregnant, or breastfeeding 
  • You are taking any other medications, including supplements, traditional medications and herbal remedies
  • You have liver or kidney disease

There is not enough data on the safety of Nirmatrelvir during pregnancy and its side effects on pregnant women or their unborn child or during breastfeeding. Published observational studies on ritonavir use in pregnant women have not identified an increase in risk of major birth defects. The use of PAXLOVID during pregnancy can be considered when indicated, after discussion with your healthcare provider.

What are some common side-effects of this medication?

  • Diarrhea
  • Increase in blood pressure 
  • Change of taste
  • Muscle aches
  • Liver problems (symptoms may include: yellowing skin or the white of your eyes, dark colored urine, abdominal pain)

Contact your doctor if you have any side effects which bother you or do not go away.

These may not be all the possible side effects of PAXLOVID as it is still being studied. It is possible that all of the risks are not known at this time. Serious and unexpected side effects may occur.

What are some rare but serious side-effects that I need to seek medical advice immediately?

The symptoms of a drug allergy include one or more of the following: 

  • Swollen face/eyes/lips/tongue
  • Difficulty in breathing
  • Itchy skin rashes over your whole body

If you experience any of these symptoms, you should stop your medication and see your healthcare professional immediately.

What food or medication should I avoid when I take this medication?

Concomitant use of PAXLOVID and certain drugs may result in potentially significant and even life threatening drug interactions. It is important to check with your healthcare provider on any potential drug interactions. 

PAXLOVID may interact with some medications (e.g. some cholesterol medications, anticoagulants (‘blood thinners’), some medications for blood pressure, and immunosuppressants), hence please inform your healthcare professional of the other medications you are currently taking.

Use of PAXLOVID may also reduce the efficacy of combined hormonal contraceptives and an alternative contraceptive method or an additional barrier method of contraception (e.g. condoms) should be considered.

You need to report to your doctor the use of any prescription, non-prescription medication, or herbal products. 

Do not start taking a new medicine without telling your doctor, while you are on PAXLOVID. Your doctor can advise you if it is safe to take PAXLOVID with other medications. 

How should I store this medication?

Store in a cool and dry place, away from direct sunlight. Keep this medication away from children. 


How should I throw away this medication safely?

Pack the medication into a bag and bring it back to the pharmacy where you received the medication from.


DISCLAIMER: This information sheet mentions some of the more common or important risks of the medication. This list is NOT meant to be, and CANNOT be exhaustive.



Please take note that the above is not a complete list of all possible side effects. If you have any concerns about your medication or if you have other side effects that you think are caused by this medication, please consult your doctor or pharmacist.

If you take more than the recommended dose, please seek medical advice immediately. The information provided on this page does not replace information from your healthcare professional. Please consult your healthcare professional for more information.

This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (National Healthcare Group, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore. The content does not reflect drug availability and supply information in pharmacies and healthcare institutions. You are advised to check with the respective institutions for such information.

Last updated in Apr 2022.

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