They were a staple on cable news for years.
They're gone now because last year the FDA pulled the drug from the market due to cancer risks.
Lookup how many FDA approved drugs were later pulled from the market due to side effects that had been previously unknown.
Ranitidine helps the ACE-2 receptor to reject SARS-CoV-2.
Tagamet and Benadryl combined have been found to shrink tumors in dogs and Tagamet apparently started out as an anti-cancer drug (IIRC prostate cancer).
Similar category to Zantac, but Tagamet is cimetidine.
Zantac is Ranitidine, which is a histamine-2 blocker. Pepcid, which is Famotidine, is also a histamine-2 blocker and is part of the FLCCC protocol for COVID-19. Cimetidine is also a histamine-2 blocker.