Others have probably beaten me to it, but antibiotics do nothing to stop viruses - absolutely nothing at all. They stop the secondary effects of a virus that lead to bacterial infection, but it would be terribly unwise to take Z-pack as a prophylactic if that’s what you are suggesting.
When you get a viral infection of the lungs, your lungs will produce an inflammatory response as a way to eject the virus and to give your body time to build up antibodies, and hopefully, immunity.
The problem is that this inflammatory response is fertile ground for a secondary bacterial infection. The deeper into the lungs the fluid goes, the greater the danger for a bacterial infection. It’s the bacteria within the lung that antibiotics fight - your body could be producing antibodies to fight of the initial virus at the same time that your body is struggling to keep bacteria from multiplying and spreading into the bloodstream, or struggling to keep the bacteria from drowning you in your own fluids.
But it does nothing to stop the virus itself. It doesn’t kill the virus. It doesn’t help build antibodies. Once you’ve got the virus, you’ve got it.
Amantadine was fairly useless for the flu even before local resistance, at best reducing symptoms by days. But you are right it is a dopamine agonist. I just didn’t want to get into the mechanisms of all the reverse transcriptases and more complex things.
I was just hoping to make the point viruses act differently and antibiotics vary a lot from each other. So best not to throw the baby out with the bath water even if a typical antibiotic does little for a typical viral infection.