Pepcid ( generic famotidine)
Is being investigated as a potential COVID-19 treatment drug
at nine times the usual dose taken for hearburn:

https://medicalxpress.com/news/2020-04-common-heartburn-drug-covid-hospital.html

Edit:

A longer article that says a classified military project that identifies existing drugs for new bio-threats was involved in this:

https://www.sciencemag.org/news/202...sts-heartburn-remedy-against-coronavirus

Sample quote

Anecdotal evidence has encouraged the Northwell researchers. After speaking to Tracey, David Tuveson, director of the Cold Spring Harbor Laboratory Cancer Center, recommended famotidine to his 44-year-old sister, an engineer with New York City hospitals. She had tested positive for COVID-19 and developed a fever. Her lips became dark blue from hypoxia. She took her first megadose of oral famotidine on 28 March. The next morning, her fever broke and her oxygen saturation returned to a normal range. Five sick co-workers, including three with confirmed COVID-19, also showed dramatic improvements after taking over-the-counter versions of the drug, according a spreadsheet of case histories Tuveson shared with Science. Many COVID-19 patients recover with simple symptom-relieving medications, but Tuveson credits the heartburn drug. “I would say that was a penicillin effect,” he says.
End quote