The antidepressant fluvoxamine seems to restrain some of the more serious complications of COVID-19, reports a study of adult outpatients with mild-to-moderate symptoms.1 Researchers say the drug also appeared to lower the chances for them requiring supplemental oxygen and hospitalization.

The patients who took fluvoxamine did not develop serious breathing difficulties or require hospitalization for problems with lung function. Most investigational treatments for COVID-19 have been aimed at the very sickest patients, but it’s also important to find therapies that prevent patients from getting sick enough to require supplemental oxygen or to have to go to the hospital. Our study suggests fluvoxamine may help fill that niche.”

says Dr. Eric J. Lenze, professor of psychiatry at Washington University in St. Louis.

Preliminary Study

In this preliminary study, which involved 152 patients infected with SARS-CoV-2, the virus that causes COVID-19, researchers compared the outcomes of those treated with fluvoxamine to the outcomes of those given an inactive placebo. After 15 days, none of the 80 patients who had received the drug experienced serious clinical deterioration. Meanwhile, six of the 72 patients given placebo (8.3%) became seriously ill, with four requiring hospitalization.

Fluvoxamine, usually prescribed to treat obsessive-compulsive disorder (OCD), social anxiety disorder, and depression, belongs to the class of drugs known as selective serotonin-reuptake inhibitors (SSRIs). Unlike other SSRIs, fluvoxamine interacts strongly with a protein called the sigma-1 receptor. That receptor also helps regulate the body’s inflammatory response.

There are several ways this drug might work to help COVID-19 patients, but we think it most likely may be interacting with the sigma-1 receptor to reduce the production of inflammatory molecules. Past research has demonstrated that fluvoxamine can reduce inflammation in animal models of sepsis, and it may be doing something similar in our patients,

says senior author Angela M Reiersen.

The drug’s effects on inflammation could prevent the immune system from creating an overwhelming response, thought to occur in some COVID-19 patients who seem to improve after a few days of illness and then worsen, Reiersen says. Many of those patients end up hospitalized, and some die.

Remote Research

Since it took place during the pandemic, researchers conducted the study remotely. When a symptomatic patient tested positive and enrolled in the study, research staff delivered the medication or inactive placebo to them, along with thermometers, automatic blood pressure monitors, and fingertip oxygen sensors.

Our goal is to help patients who are initially well enough to be at home and to prevent them from getting sick enough to be hospitalized. What we’ve seen so far suggests that fluvoxamine may be an important tool in achieving that goal,

says Dr. Caline Mattar, assistant professor of medicine in the infectious diseases division.

For two weeks, subjects took either the antidepressant drug or placebo while having daily interactions with members of the research team — via phone or computer. That allowed patients to report on their symptoms, oxygen levels, and other vital signs. If patients suffered shortness of breath or went to the hospital for pneumonia, or their oxygen saturation levels fell below 92%, researchers considered their conditions to have deteriorated.

The good news is that not a single person taking the active medication experienced deterioration. We believe this drug may be the reason, but we need to study more patients to make sure,

Reiersen says. The researchers will start an expanded study within weeks.

The work was supported by the Taylor Family Institute for Innovative Psychiatric Treatment at Washington University, the Bantly Foundation, the the National Institutes of Health, and the COVID-19 Early Treatment Fund.


  1. Lenze EJ, Mattar C, Zorumski CF, et al. Fluvoxamine vs Placebo and Clinical Deterioration in Outpatients With Symptomatic COVID-19: A Randomized Clinical Trial. JAMA. November 12, 2020. doi:10.1001/jama.2020.22760 ↩︎


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