Why Paxlovid:

According to Pfizer’s clinical trial data from 2021 (participants enrolled by 09/29/2021) which it used for FDA approval, subjects who took Paxlovid were 89% less likely to develop severe illness and death from COVID than those taking a placebo. Grain of salt here includes: 

  • In the original study, participants took Paxlovid within 3 days of symptom onset for the 89% reduction statistic
    • Later studies showed that those who took it within 5 days had the following outcomes: 1% in the Paxlovid group were admitted up to day 28 (no deaths) and 6.7% in the placebo group (10 deaths out of 612 participants).
    • Hence based on this later data, it is recommended to prescribe within 5 days of symptom onset
  • Data was from 2021 which did not include Omicron and all its further variants
  • This is Pfizer’s data
    • Three more studies have been used to bolster the claim that Paxlovid should be effective in any “highly contagious COVID variant” – two of these were also conducted by Pfizer solely and the 3rd was conducted by Pfizer in partnership with the Icahn School of Medicine

Who is Paxlovid for:

The quick and easy answer for this is “non-hospitalized patients with mild to moderate COVID-19 who are at high risk of progressing to severe disease.” The more correct answer with lots of considerations includes:

  • Anyone 65 or older
  • OR anyone 12 or older with a medical condition that puts you at risk for development of severe Covid-19. The CDC includes the following medical conditions that qualify:
    • Cancer (history included), CKD (with limitations; you have to have a GFR as defined below), chronic liver disease (but not worse than Child-Pugh Class B), chronic lung disease (which can include asthma, COPD, bronchiectasis, BPD, pulmonary fibrosis, PE, pulmonary hypertension), CF, dementia “or other neurologic conditions” (left open to interpretation), diabetes, disabilities (broad, also left open to interpretation), “heart conditions” (which include, HF, CAD, cardiomyopathies, HTN), HIV, immunocompromised state, mental health conditions, overweight/obesity (that’s right, BMI >25 included), physical inactivity (this is quite broad), pregnancy (and up to 42 days post-partum), sickle cell disease or thalassemia, smoking: current or former, transplant patients, stroke/CVD pts, substance use disorder (including alcohol among illicit drugs), and present TB infection
  • Weigh at least 88 lbs
  • Have a positive NAA or Ag test
  • Have mild to moderate Covid-19 symptoms
  • Can start treatment within 5 days of symptom onset
  • Not requiring hospitalization when treatment is initiated
  • Have a GFR of >/=30 (30-59 needs dose adjustments)
  • Not be on a lot of other medications that Paxlovid has drug-drug interactions with (here’s a fun tool from Liverpool where you can type all the medications a patient is on to see if they’re on something that would preclude your prescribing of Paxlovid: https://www.covid19-druginteractions.org/checker)
    • There’s also this where a list of about 103 medications can be found on page 10. Some of them can’t be taken together at all and some you need to consider risks/benefits of discontinuing for the time being. https://www.fda.gov/media/155050/download
      • Essentially many of the medications used to treat the above listed “high risk medical conditions” are on here. I like to think of Paxlovid as the Schrodinger’s cat of treatments: it is for everyone and for no one at the same time.

How does it work:

Targets proteins on the SARS-CoV-2 virus to prevent intracellular replication

The prescribing dose:

  • Prescriptions should specify the numeric dose of each active ingredient within Paxlovid: 300 mg nirmatrelvir (two 150 mg tablets) with 100 mg ritonavir (one 100 mg tablet), with all three tablets taken together twice daily for five days.
  • For moderate renal impairment (i.e. eGFR ≥30 to <60ml/min): Reduce dosage to 150 mg nirmatrelvir (one 150 mg tablet) with 100 mg ritonavir (one 100 mg tablet) taken together twice daily for five days.

Where to prescribe:

Here’s the “quick” checklist for providers for prescribing: https://www1.nyc.gov/assets/doh/downloads/pdf/covid/providers/paxlovid-providers-checklist.pdf

Here’s the paperwork to give to your patients:


Finally, the DOH website that provides much of the relevant info here: https://www1.nyc.gov/site/doh/covid/covid-19-providers-treatments.page

May 2022