B-QuiCK: Prescribing nirmatrelvir/ritonavir (Paxlovid)

Initiate nirmatrelvir/ritonavir as soon as possible once the patient has COVID-19; it must be started within five days of symptom onset
- An advanced prescription can be given if patients meet all aspects of the access criteria except having COVID-19. The medicine will only be dispensed once they have COVID-19.
Undertake a clinical review of the patient to assess suitability prior to prescribing (see below for more details):
- Establish whether access criteria are met
- Review most recent eGFR result (if available)
- Check for potential medicine interactions
Endorse on the prescription that the patient meets access criteria. Also include:
- Date of symptom onset
- eGFR result if known renal impairment
- Your contact number
Manage patient expectations:
- They still may experience symptoms
- They still can develop COVID-19 again in the future
- Their risk of COVID-19 progressing to severe disease and being hospitalised or dying from COVID-19 is reduced
Nirmatrelvir/ritonavir is generally well tolerated. Taste disturbances, gastrointestinal upset (e.g. nausea, diarrhoea), hypertension and myalgia can occur.
- Some patients may experience viral rebound after treatment; symptoms are usually mild and can be self-managed. Further antiviral treatment is not indicated.

Clinical review

Check access criteria are met

If access criteria are clearly met (see box) then nirmatrelvir/ritonavir treatment is appropriate.

In summary, this includes all people aged 65 years or over, people of any age with a high risk health condition or vulnerability and all other people aged 50 – 64 years if they have additional factors that increase their risk of severe outcomes.

COVID-19 antiviral access criteria

Patients are eligible for funded COVID-19 antiviral treatment if they have:

Confirmed (or probable) symptomatic COVID-19, or symptoms consistent with COVID-19 and are a household contact of a positive case; AND
Symptom onset within the last five days; AND
No requirement for supplemental oxygen due to COVID-19 infection;^* AND
ANY of the following:

Are aged ≥ 65 years; OR
Are aged ≥ 50 years and considered by their healthcare professional to be at high risk of hospitalisation or death from COVID-19 due to factors not covered below; OR
Are immunocompromised and not anticipated to reliably mount an adequate immune response to COVID-19 vaccination or infection; OR
Had a previous admission to critical or high dependency care directly as a result of COVID-19; OR
Has Down syndrome; OR
Has sickle cell disease; OR
Receives Disability Support Services from the Ministry of Social Development (previously administered by the Ministry of Disabled people | Whaikaha); OR
Has pre-existing high risk due to a health condition and needs direct family/whānau or external disability care most days; OR
Has pre-existing severe frailty and/or vulnerability due to one or more severe health conditions;^† OR
Has any combination of ≥ 3 high-risk factors for severe illness from COVID-19

N.B. The antiviral cannot be used concurrently with another COVID-19 antiviral.

* Supplemental oxygen to maintain oxygen saturation > 93%, or at or above baseline, for patients with chronic resting hypoxia due to COVID-19 infection (excluding those with chronic resting hypoxia as a result of conditions other than COVID-19)

† Health conditions that include severe or very advanced disease including, but not limited to, severe neurological, cardiovascular, renal and respiratory conditions

To meet criteria 4.2 - Use clinical judgement of the individual circumstances of the patient (medical, personal and/or social factors). In general, consider nirmatrelvir/ritonavir in a patient aged 50 – 64 years if they have any of the following factors:

Māori or Pacific ethnicity
Socioeconomic deprivation
Are not fully vaccinated against COVID-19 (primary course) and never had COVID-19 before
One or two of the high risk factors for severe illness from criteria 4.10 if there is clinical concern about the effect on recovery from COVID-19

Prescribing: check eGFR to inform dosing

Prescribe nirmatrelvir/ritonavir according to the patients’ eGFR:
- ≥ 60 mL/min/1.73 m²: no dose adjustment required – prescribe 300 mg nirmatrelvir (two tablets) and 100 mg ritonavir (one tablet), twice daily, for five days
- 30 – 59 mL/min/1.73 m²: reduce each dose of nirmatrelvir to 150 mg (one tablet), i.e. prescribe 150 mg nirmatrelvir (one tablet) and 100 mg ritonavir (one tablet), twice daily, for five days
- < 30 mL/min/1.73 m²: Day one - prescribe 300 mg nirmatrelvir (two tablets) and 100 mg ritonavir (one tablet). Days two to five - prescribe 150 mg nirmatrelvir (one tablet) and 100 mg ritonavir (one tablet), to be taken once daily. N.B. Nirmatrelvir/ritonavir was previously contraindicated in patients with an eGFR < 30 mL/min/1.73 m², but now can be considered in this group.
Advise female patients of child-bearing potential to take extra contraceptive precautions during, and for one week after, treatment; efficacy of oral contraceptives may also be reduced
The manufacturer recommends avoiding during pregnancy and breast-feeding due to limited data, but it may be prescribed if the benefits outweigh the potential risks; seek obstetrician or infectious diseases advice and consider patient preferences before prescribing

Check for potential medicine interactions

Check what medicines, including over-the-counter and complementary and alternative medicines, the patient is currently taking and the potential severity of any interaction; use the University of Liverpool COVID-19 Drug Interaction Checker or NZF interactions checker
Depending on the indication of the medicine and interaction severity, either:
- Temporarily stop the interacting medicine
- Reduce the dose of the interacting medicine
- Continue with the interacting medicine at the current dose but closely monitor the patient
If the patient is taking a medicine that is managed in secondary care, seek advice from the relevant specialist prior to prescribing
Clearly communicate any changes to the patient’s treatment regimen with them, including when their regular medicines should be restarted (ideally verbally and in writing)