There's interest in studying famotidine because it's inexpensive and considered to be very safe, and one study has suggested the drug helps hospitalized Covid patients.

One patient -- the only patient to describe worsening of any symptoms while taking the drug -- described becoming more tired after taking famotidine.

When the 10 patients were struck by Covid in March and April, one of the study coauthors who knew the drug was being studied in hospitalized patients suggested they take famotidine.

"He suggested they take famotidine and begin tracking their symptoms in a fastidious way."

The report notes that the patients were enrolled in the study consecutively, meaning that the authors didn't cherry-pick their study subjects and reject ones who got worse after taking the drug.

That's why the Northwell researchers are planning a double-blind clinical trial, where patients sick with Covid at home will be randomly assigned to take either famotidine or a placebo, and neither the patients nor the doctors will know who is taking which.

An earlier study by doctors at Northwell and Columbia University found that hospitalized Covid patients who were taking famotidine were more than twice as likely to survive the infection.

Those researchers are currently conducting a clinical trial on famotidine with hospitalized Covid patients.