Special Episode 11. Anti Virals for COVID-19 with Dr Alex Tai
As case numbers and deaths continue to climb from Covid 19 infection and its many variants, two antiviral drugs have entered the market and are now available on the Australian PBS with specific prescription criteria to be met. So, what are they and what do they do?
Molnupiravir - Made by Merck in collaboration with Ridgeback Biotherapeutics was the 1st to be introduced to Australia as a trade named Lagevrio available from March 1st. This drug is a polymerase inhibitor administered as four tablets twice daily for a five-day course and works by stopping Covid 19’s genetic material from being replicated accurately. By inhibiting the virus’s own polymerase, it induces replication errors so that ultimately the virus is unable to survive with these. This is the so-called catastrophe method. A question for our guest relates to this drug’s safety…. for example: Could this drug also affect host enzymes?
Paxlovid - takes a different approach the drug consists of Nirmatrevir, and an existing drug called Ritonavir. These are protease inhibitors affecting the viral proteases which cut apart long strands of non-functional viral protein into smaller functional proteins. Nirmatrevir is the drug working on this whilst Ritonavir prevents other enzymes from destroying Nirmatrevir. Ritonavir may be found elsewhere and used in anti-HIV cocktails. Paxlovid is also taken BD for five days.
These drugs are most effective when given early and the PBS criteria states these drugs are for adults who have mild to moderate COVID-19 confirmed by a PCR or medically verified RAT and who can start treatment within 5 days of symptom onset if:
o they are 65 years of age or older, with two other risk factors for severe disease (as increasing age is a risk factor, patients who are 75 years of age or older only need to have one other risk factor); or
o they identify as Aboriginal or Torres Strait Islander origin and are 50 years of age or older with two other risk factors for severe disease, or
o they are moderate to severely immunocompromised.
We should draw attention to:
Evushield (Tixagevimab+ Cilgavimab) and Sotrovimab
We need a primer on who should receive these and will discuss this with our guest shortly.
And what about other drugs that have at times perhaps controversially been recommended around the globe such as?:
Chloroquine and Ivermectin
And then is there an early place for steroid prescription?
To expand our knowledge on this emerging and complex subject please welcome to the podcast Dr Alex Tai Infectious Diseases specialist with a special interest in public health, tropical medicine, multi drug microbial resistance and travel medicine.
For more information on this episode please visit: https://www.gihealth.com.au/everyday-medicine-podcast-blog/special-episode-11-anti-virals-for-covid-19-with-dr-alex-tai
References:
Dr Alex Tai-Infectious Diseases Physician-
www.bawbawphysicians.com.au
What GPs need to know about the new Covid antivirals: www1.racgp.org.au
Antiviral treatments for Covid 19-NPS MedicineWise-www.nps.org.au
Liverpool COVID -19 Interactions : www.covid19-druginteractions.org
To be a guest on the show or provide some feedback, I’d love to hear from you: manager@gihealth.com.au
Dr Luke Crantock MBBS, FRACP, is a gastroenterologist in practice for over 25 years. He is the founder of The Centre for GI Health, based in Melbourne Australia and is passionate about educating General Practitioners and patients on disease prevention and how to manage and improve their digestive health.