While Oxford scientists now say it could be September, at the earliest, before we see a safe and effective coronavirus vaccine—and Harvard scientists are saying that we may need to practice social distancing until 2022—other medical researchers are looking for existing treatments that may help with COVID-19. One such treatment is famotidine, the active ingredient in the popular over-the-counter heartburn medication Pepcid AC.
Science Magazine revealed on April 26 that Northwell Health in the greater New York City area has quietly begun clinical trials to treat COVID-19 patients with famotidine, by intravenously administering the drug at nine times the recommended heartburn dose.
Dr. Kevin Tracey, president of Feinstein Institutes for Medical Research at Northwell Health, said that preliminary results of the clinical trials—which have been underway since April 7—could even be ready by May. A total of 1,174 patients—including 187 who were critically ill—have taken part in the study at Northwell as of April 25.
Why famotidine, exactly?
Dr. Michael Callahan, an infectious disease specialist based out of Massachusetts General Hospital, was the first to call attention to the potential use of famotidine in the U.S. In studying coronavirus cases in Wuhan, China, Callahan learned that the virus was killing as many as one out of five patients older than 80. And of that 20% of patients who survived, one thing they had in common was that many had been taking heartburn medication.
In a twist, Callahan observed that lower-income patients were typically surviving longer than their wealthier counterparts who were also taking medication for heartburn. “Why are these elderly peasants not dying?” Callahan and his Chinese colleagues wondered.
After reviewing patient records, Callahan’s team had found poorer survivors with chronic heartburn typically had been taking famotidine—as opposed to wealthier Chinese patients who had been using the relatively more-expensive omeprazole, commonly known as Prilosec.
These studies of Chinese COVID-19 patients had not yet been published, but Callahan’s findings were enough to encourage scientists in the U.S. to explore the drug’s potential.
How can famotidine work to treat COVID-19?
It should be stressed that there is nothing conclusive yet—in theory, the structure of famotidine suggests that it could stop the virus from replicating, similar to the way that protease inhibitors treat the HIV virus.
“Famotidine is a histamine receptor blocker,” Dr. Solomon L. Lerer, a gastroenterologist in Florida, told Health.com, in that the compound specifically blocks the H2 receptors that play a role in producing acid in the stomach, which can lead to heartburn.
“Famotidine is most commonly used to treat gastroesophageal reflux disease,” added Dr. Abraham Khan, director of the Center for Esophageal Diseases at NYU Langone Health. “Often, it works best in patients with mild gastroesophageal reflux disease (GERD) symptoms that do not need a daily stronger acid-suppressive medication, such as a proton pump inhibitor (PPI).”
Again, there are huge variables at play. However, if famotidine is successful in treating coronavirus, it would be easy to administer on a widespread scale.
“It’s generic, it’s plentiful and it’s inexpensive,” Tracey told CNN. “We don’t know if it has any benefit. We really don’t. I swear we don’t. People are hoping for anything. But we need to do this clinical trial.” He also advised against people taking the potential cure into their own hands, as those in the study are taking mega-doses of the drug. “You should not go to the drugstore and take a bunch of heartburn medicine,” he said.
“There are many examples in the history of medicine where a drug that was designed for one purpose turns out to have an effect on another disease,” Tracey added.
How does famotidine differ from hydroxychloroquine?
Famotidine may inevitably draw comparisons to hydroxychloroquine—the drug being used to treat diseases like malaria and lupus that was widely touted by President Donald Trump in March and April. Claims of the drug’s efficacy against coronavirus rely on its anti-inflammatory properties. These claims, however, are unproven, and preliminary findings have suggested that high dosages of chloroquine should not be recommended for COVID-19 treatment due to potential safety hazards.
The initial hype surrounding hydroxychloroquine has made Tracey wary of sparking similarly premature enthusiasm when it comes to famotidine. “If it does work, we’ll know in a few weeks,” he said.