Covid anti viral

Is Covid antiviral safe for us if we are on antiviral ?

I took COVID Antiviral 4 times. And I am on Hepatitis B drug also.

So far I don’t see any complications yet. But I have no idea for the long term.

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Dear Senhour,

There are no clinical data on this subject that I am aware of. However, both Paxlovid and Velkury (the approved antivirals for SARS CoV2 infection) are very short term treatments. There are unlikely to be any long term complications.

Best regards,


I was advised by my hepatologist at UCSF not to take Paxlovid while taking Vemlidy. Ask for alternative Covid antivirals that do not interact adversely with Vemlidy.

Dear BBritt,

The advice of your hepatologist is brings up an interesting discussion point.

Paxlovid is actually a combination of two drugs. The first (nirmatrelvir) is the direct acting antiviral agent which inhibits the SARS CoV2 protease. The second (ritonavir) inhibits a liver enzyme (CYP3A) which metabolizes nirmatrelvir, thus increasing the levels of nirmatrelvir in the body. Ritonavir is similarly used in combination with other drugs which are metabolized by CYP3A to improve their efficacy.

Obviously a potential concern here would be that taking paxlovid would increase the levels of TAF (because of the ritonavir that it contains). However, the metabolism of tenofovir is largely CYP3A independent so the co-administration of Vemlidy and Paxlovid would be expected to have little impact (if at all) on the levels of TAF. Additionally, the typical course of Paxlovid is only 5 days.

Best regards,


Thank you. I ended up being too late to take the antiviral. 72 hours after positive COVID results.
Good information to know for next time.