A widely prescribed antidepressant could help people struggling with long Covid fatigue, a new study suggests.
A randomised clinical trial compared the potential of fluvoxamine – marketed as Faverin – metformin and a placebo to reduce one of the most persistent and debilitating symptoms of long covid, fatigue.
The study, conducted by scientists at the Brazilian Biomedical Research Institute included almost 400 adults who had been experiencing fatigue for at least 90 days after falling ill with covid.
Participants were randomly assigned one of the drugs for 60 days, and asked to trac how tired they felt using a standard severity scale.
The fluvoxamine patients reported steady improvements in fatigue and quality-of-life scores over 60 to 90 days, with fewer side effects than a placebo. It also boosted overall quality-of-life scores.
Metformin, which lowers insulin and blood sugar even in people without diabetes, showed no significant benefit. While all treatments were generally safe, fluvoxamine had fewer reported side effects.
The findings were published in the Annals of Internal Medicine, and the authors say fluvoxamine may be a viable treatment for long Covid fatigue – although its long-term effects are still unknown.
An important limitation is that the study did not assess participants’ history of depression so it is unclear whether the effect was a direct impact on long Covid or related to underlying depression.
Long covid is defined as covid symptoms which last longer than 12 weeks after infection
Professor Christiaan Vinkers from the Amsterdam University Medical Centre, who was not involved in the study, said that the study is promising but the pill is unlikely to be a golden bullet.
He said: ‘This randomised placebo-controlled trial provides encouraging evidence that fluvoxamine may reduce fatigue in a selected group of patients with long Covid.
‘The study appears methodologically solid with low dropout and a consistent signal on fatigue and quality of life.
‘Still, the findings should be interpreted cautiously because the main outcome was self-reported and the population excluded important groups such as patients with depressive or anxiety disorders.
‘In addition, the study focused primarily on fatigue and did not assess other long COVID features such as post-exertional malaise (PEM), autonomic symptoms including POTS, or cognitive impairment, nor did it include biomarker measures to help understand underlying mechanisms.
‘The results are promising, but replication is essential, ideally in broader patient groups and with outcomes that capture the full spectrum of long Covid.’
Long Covid is defined as covid symptoms lasting for longer than 12 weeks. There is currently no cure, and the condition is still being researched.
Fluvoxamine is available on prescription in the UK under the name Faverin
Experts believe it is caused by viral persistence, blood clots, and an autoimmune-like response, which can lead to ongoing symptoms such as fatigue, brain fog, heart palpitations, anxiety, insomnia and problems with the lungs, heart or stomach.
In some cases, these symptoms have left patients feeling so unwell that they say they have considered assisted suicide.
Many people experience weakness or tiredness for months after infection, with even routine tasks like a busy day at work or washing the dishes leaving them drained.
Previous studies have suggested the condition may be caused by the immune system remaining overactive even after the initial Covid infection has been cleared.
Similar symptoms have also been recorded in people after recovering from other viral infections, in a condition called post-viral syndrome, such as the flu and Epstein-Barr virus.
There is a cohort of people, including doctors, however, who do not believe that long Covid is a real condition because of its wide variety of symptoms and the fact that there is no single test for the condition.
Last year, a US study identified eight potential categories of long Covid, which range from mild to severe.
Fluvoxamine belongs to a class of drugs called selective serotonin reuptake inhibitors, or SSRIs, which boost serotonin in the brain to improve mood.
The drug also appears to calm the immune system, preventing it from overreacting, which may explain why it eases long covid fatigue. It is most commonly used to treat obsessive-compulsive disorder or social anxiety.
In 2024, more than 91 million antidepressant prescriptions were dispensed in England, a record high.
