Famotidine, a drug used to reduce stomach acid production, indigestion and heartburn, has reportedly been successful in treating coronavirus symptoms, according to a Science Magazine study in which the drug underwent clinical trials in COVID-19 patients.The drugs, called H2 blockers, lower acidity in the stomach and prevent the burning sensation in the esophagus that indicates acid reflux. "Famotidine is commonly used for gastric acid suppression but also has recently gained attention as an antiviral that may inhibit SARS-CoV-2 replication," the study authors wrote in their research.Following the news, the United States Food and Drug Administration added famotidine, the active compound in the over-the-counter heartburn drug-brand Pepcid, to its list of drug shortages."Based on what we've learned in this study, it's encouraging," co-author Dr. Joseph Conigliaro, a physician at Northwell Health said, according to CNN. "This association is actually really compelling."The study analyzed 1,620 hospitalized patients with COVID-19. Some 84 (5.1%) of them received famotidine within 24 hours of hospital admission. Eight of the 84 patients tested died or were put on a ventilator. "Compared to the rest of the patients, those who received famotidine had a greater than two-fold decreased risk of either dying or being intubated," the Columbia University Irving Medical Center authors said, according to CNN.However, despite the study's success, there is no concrete evidence that the drug is effective in treating COVID-19. The study authors noted that "randomized controlled trials are warranted to determine whether famotidine therapy improves outcomes in hospitalized COVID-19 patients.""It is not clear why those patients who received famotidine had improved outcomes," the study authors added, according to CNN. "This is merely an association, and these findings should not be interpreted to mean that famotidine improves outcomes in patients hospitalized with COVID-19."The study was reportedly inspired by Chinese researchers who noted that lower-income citizens "seemed to do well on famotidine" while the wealthier population used a more expensive drug less effective against treating COVID-19 symptoms, according to Dr. Kevin Tracey, president of Feinstein Institutes for Medical Research at Northwell Health.With regard to the famotidine shortages, the cause is likely from the ongoing butterfly effect stemming from when rantidine, the active compound in Zantac, a separate heartburn medication, became scarce in late 2019; and is not "directly rooted" to the new study, according to Drug Topics.“I had to order it at Amazon a couple of months ago because we can’t get it in our store,” pharmacist Kyona Nason told the publication popular with pharmacists. "It’s been a problem for months since the various ranitidine recalls.”According to Drug Topics, Teva currently has all of their famotidine tablets on back-order and doesn't expected more to be released until late this year.