Paxlovid (nirmatrelvir plus ritonavir)

Adults who have COVID-19 confirmed by positive nucleic acid test result or medically verified RAT, who are not hospitalised for COVID-19 at the time of prescribing and who can start treatment within five days of symptom onset, can be prescribed PBS-subsidised Paxlovid if:

• they are 70 years of age or older*
• they are 18 years of age or older and moderately to severely immunocompromised**, with risk of progression to severe COVID-19 disease due to the immunocompromised status OR have experienced past COVID-19 infection resulting in hospitalisation AND have at least one sign or symptom attributable to COVID-19
• they identify as Aboriginal or Torres Strait Islander origin, and are 30 years of age or older, are at high risk and have at least one sign or symptom attributable to COVID-19***
• they are 50 years of age and are at high risk***

When prescribing Paxlovid via the PBS, ensure the patient meets the eligibility criteria outlined on the PBS listing.

Paxloxid is contraindicated in patients with renal and hepatic impairment and with concomitant use of a number of medicines. Thoroughly review the Product Information before prescribing. 

The standard dose of Paxlovid is 300 mg of nirmatrelvir (two 150 mg tablets) together with 100 mg of ritonavir (one tablet). All tablets must be taken together, with or without food. The tablets should be swallowed whole and not chewed, broken or crushed.

The tablets are dispensed in pre-dosed blistered cards.

Paxlovid is taken every 12 hours for five days. If patients miss a dose, they should not take a double dose to make up for the missed dose and should take their next dose as scheduled. Patients should not stop taking Paxlovid or change their dosage without speaking to their GP or physician.

Dosage adjustment for patients with renal impairment

Patients with moderate renal impairment (eGFR ≥30 to <60 mL/min) can be prescribed a lower dose of 150 mg nirmatrelvir (one tablet) with one 100 mg tablet of ritonavir. Patients receiving an adjusted dose must be made aware that as the tablets are dispensed in pre-dosed blistered cards, only one tablet of nirmatrelvir with the tablet of ritonavir should be taken every 12 hours.

Paxlovid is contraindicated in patients with severe renal impairment (eGFR <30 mL/min).

Refer to the Product Information for further details on dose adjustment.

Paxlovid is contraindicated for patients with severe renal (eGFR <30 mL/min) or severe hepatic impairment, and those who are allergic to nirmatrelvir or ritonavir or any of the ingredients listed in the Product Information.

There are a number of medicines that are contraindicated for concomitant use with Paxlovid. People taking any medicine listed in section 4.3 of the Product Information should not be prescribed Paxlovid.

There are a number of medicines which have established and potentially significant interactions with Paxlovid and may cause serious or life-threatening side effects or affect how the medicine works.

Refer to the clinical comments in section 4.5 of the Paxlovid product information for each of the medicines.

Paxlovid is not recommended during pregnancy and in people of childbearing potential not using contraception. Breastfeeding should be discontinued during treatment with Paxlovid and for 48 hours after the last dose.

As with most medicines, Paxlovid can cause side effects and, though most of these will be minor and temporary, more severe side effects may need medical treatment. The most common side effects of Paxlovid include vomiting, diarrhoea, headache, high blood pressure, aching muscle, muscle tenderness or weakness not due to exercise, and changes in taste or a metallic taste in the mouth. Patients should be advised to speak with their GP or prescribing physician if they are concerned about any side effects while taking Paxlovid.