Fluvoxamine, an antidepressant used to treat obsessive compulsive disorder and depression, was found to significantly reduce the risk of hospitalization from Covid-19, according to a study published in Lancet Global Health.

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Study details

For the study, researchers looked at 1,497 Covid-19 patients in Brazil, half of whom were given 100 mg of fluvoxamine twice a day for 10 days while the other half received a placebo. All of the participants were at high risk for developing severe Covid-19 symptoms because of their age and comorbidities, and the majority were unvaccinated.

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After their 10-day regimen was complete, the participants were followed for four weeks. The researchers found that overall risk of hospitalization among those who were given fluvoxamine was reduced by about one-third.

While some patients stopped taking the drug, those who reported taking fluvoxamine for at least eight of the 10 days saw a 66% reduction in hospitalization risk and a 91% reduction in death risk.

Could fluvoxamine become a standard Covid-19 treatment?

Fluvoxamine is part of a class of antidepressants called selective serotonin reuptake inhibitors and costs $4 for a 10-day course. Other smaller studies have suggested the drug could be useful as a Covid-19 treatment, although none were as large as the Lancet study.

The study authors concluded that, given the drug's "safety, tolerability, ease of use, low cost, and widespread availability, these findings might influence national and international guidelines on the clinical management of Covid-19."

They added that their study shows the fluvoxamine "compares favorably with the treatment effects of more expensive treatments including monoclonal antibodies for outpatient treatment."

"This is exciting data," Daniel Griffin, chief of infectious diseases at ProHealth New York, said. "There are several other trials that are in progress, and if they confirm this finding, this may end up being standard of care."

However, some questions remain about fluvoxamine's effectiveness in treating Covid-19. Penny Ward, a visiting professor in pharmaceutical medicine at King's College London, noted that since most of the participants in the study were unvaccinated, it's not clear how well fluvoxamine would work in vaccinated patients.

In an accompanying editorial, Otavio Berwanger, from the Hospital Israelita Albert Einstein in Brazil, wrote that it's unclear whether fluvoxamine "has an additive effect to other therapies such as monoclonal antibodies and budesonide," nor is it clear what "the optimal fluvoxamine therapeutic scheme" is.

"Finally, it is still unclear whether the results from the [study] extend to other outpatient populations with Covid-19, including those without risk factors for disease progression … and those infected with the delta variant or other variants," Berwanger added. (Sclafani, Axios, 10/27; Mueller, New York Times, 10/27; Johnson, Associated Press, 10/27; Phend, MedPage Today, 10/27; Toy, Wall Street Journal, 10/27)