An inexpensive antidepressant already on pharmacy shelves has demonstrated meaningful relief for the debilitating fatigue that plagues long COVID patients, according to a major international clinical trial. Fluvoxamine, marketed under the brand name Luvox and commonly prescribed for depression, reduced exhaustion and improved quality of life in adults struggling with persistent post-infection symptoms.
The randomized, placebo-controlled trial, published in the Annals of Internal Medicine, tested fluvoxamine alongside metformin, a diabetes medication, in 399 Brazilian adults who had endured fatigue for at least 90 days following confirmed SARS-CoV-2 infection. After 60 days of treatment, fluvoxamine outperformed placebo with a 99 percent probability of effectiveness. Participants on the medication also reported gains in overall quality of life across multiple measures.
The trial was led by researchers from McMaster University in Canada, with collaborators from the University of British Columbia, Stanford University, the University of Pittsburgh, Duke University, and Georgetown University. Clinical sites operated in Belo Horizonte and throughout Minas Gerais in Brazil.
Edward Mills, senior author and professor at McMaster's Department of Health Research Methods, Evidence, and Impact, called the finding a breakthrough for patients waiting for evidence-based treatment options. "Fluvoxamine showed consistent and meaningful benefits, and because it's already widely used and well understood, it has clear potential for clinical use," Mills said.
Fatigue remains among the most frequent and disabling symptoms reported by long COVID sufferers. For some, the exhaustion is severe enough to prevent work, derail family responsibilities, and disrupt daily living. Despite affecting an estimated 65 million people worldwide, proven therapies remain scarce, with most medical guidance limited to supportive strategies like activity pacing and symptom management.
The research team selected both medications because of their low cost and existing biological rationale for potential benefit against long COVID fatigue. Metformin, however, failed to produce meaningful improvement in patients with established long COVID, despite earlier evidence that it could prevent long COVID development when taken during acute infection.
The trial employed a Bayesian adaptive design, allowing researchers to halt individual treatment groups once evidence became statistically clear. This approach accelerates conclusions while preserving scientific rigor. Gilmar Reis, lead author and researcher at Cardresearch in Belo Horizonte, noted that the design innovation itself matched the significance of the findings.
Researchers emphasized that fluvoxamine is not a complete solution for long COVID's complexity. The condition involves numerous symptoms and biological pathways, and the drug appears specifically effective for fatigue management. Additional studies will explore which patients benefit most, clarify the medication's mechanism, and assess whether it works synergistically with other emerging treatments.
Jamie Forrest, corresponding author and postdoctoral research fellow at the University of British Columbia, stressed the clinical urgency. "Patients want something they can try today, and this finding brings us closer to that reality," Forrest said.
The trial was funded by The Latona Foundation.
Author Jessica Williams: "This is exactly the kind of pragmatic, low-cost solution long COVID patients need right now, and the rigorous methodology behind it means clinicians can actually trust the results."
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