Antidepressant fluvoxamine shows promise easing long COVID fatigue in clinical trial

For millions of people living with long COVID, fatigue has become the defining feature of their illness—a bone-deep exhaustion that makes work impossible, that turns a trip to the grocery store into a day-long recovery project, that fractures the ordinary rhythms of family life. Until now, there has been almost nothing doctors could offer them. A new clinical trial, published in the Annals of Internal Medicine, changes that calculus. Researchers found that fluvoxamine, a cheap and widely available antidepressant sold under the brand name Luvox, significantly reduced fatigue and improved overall quality of life in people with long COVID—making it the first medication to show meaningful benefit for this disabling symptom in a rigorous clinical test.

The trial enrolled 399 adults in Brazil who had experienced persistent fatigue for at least 90 days following confirmed SARS-CoV-2 infection. Participants were divided into three groups: one received fluvoxamine, another received metformin (a common diabetes medication), and a third received placebo. All took their assigned treatment for 60 days. The researchers, drawn from McMaster University, the University of British Columbia, Stanford, the University of Pittsburgh, Duke, Georgetown, and several Brazilian institutions, were testing whether two existing, affordable medications might address a condition for which almost no evidence-based treatments exist.

Fluvoxamine outperformed placebo with a 99 percent statistical probability of genuine effectiveness. People who took it reported not only reduced fatigue but also measurable improvements across multiple measures of quality of life. Metformin, by contrast, showed no meaningful benefit for people already suffering from established long COVID fatigue—despite earlier evidence suggesting it might prevent the condition from developing in the first place if taken during acute infection.

The trial employed what researchers call a Bayesian adaptive design, a methodological approach that allowed them to stop individual treatment arms early once the evidence became sufficiently clear. This is not merely a technical detail. It means the researchers could reach reliable conclusions faster than a traditional trial would allow, while maintaining scientific rigor—a design innovation that matters as much as the findings themselves.

Edward Mills, the senior author and a professor at McMaster's Department of Health Research Methods, Evidence, and Impact, framed the result in terms of what patients have been asking for: "This is an important step forward for patients who have been desperate for evidence-based options." The medication is already widely used, well understood, and inexpensive. There are no surprises lurking in its pharmacology. That means clinicians could begin prescribing it for long COVID fatigue almost immediately, rather than waiting years for a drug to move through development and approval.

Yet the researchers are careful not to oversell what they have found. Fluvoxamine is not a cure for long COVID. The condition involves multiple symptoms and multiple biological pathways, and this medication appears specifically useful for fatigue management. Long COVID affects an estimated 65 million people worldwide, and most current medical guidance still relies on supportive strategies—activity pacing, symptom management, rest. That landscape has not fundamentally changed.

What has changed is that clinicians now have something concrete to offer. Further research will be needed to identify which patients are most likely to benefit, to understand the mechanism by which fluvoxamine works, and to explore whether it might be combined with other emerging treatments. But for the first time, there is a medication with strong clinical evidence behind it. For people who have been waiting for any tool that might help them reclaim their lives, that is not nothing.