They noticed that elderly patients in China that were on Pepcid generally had better outcomes than those that weren't. Early on, it was thought that it might have been preventing replication of the virus, but the research is showing that it doesn't. The theory now is that it may reduce the inflammatory response and prevent the cytokine storm.

Pepcid is a histamine blocker, which gives it anti inflammatory properties. It's often given to people with allergic reactions as well.