People taking a class of antidepressants called selective serotonin reuptake inhibitors (SSRIs), particularly fluoxetine, were significantly less likely to die of Covid-19, according to a study.
The results add to a body of evidence indicating that SSRIs may have beneficial effects against the worst symptoms of Covid-19, although large randomised clinical trials are needed to prove this.
"We can't tell if the drugs are causing these effects, but the statistical analysis is showing significant association," said Marina Sirota, Associate Professor of pediatrics at University of California San Francisco. "There's power in the numbers."
The joint UCSF-Stanford research team analysed electronic health records of 83,584 adult patients diagnosed with Covid-19 between January and September, 2020. Of those, 3,401 patients were prescribed SSRIs.
The researchers compared the outcomes of patients with Covid-19 on SSRIs to a matched set of patients with Covid-19 who were not taking them.
The results showed that patients taking fluoxetine were 28 per cent less likely to die; those taking either fluoxetine or another SSRI called fluvoxamine were 26 per cent less likely to die; and the entire group of patients taking any kind of SSRI was 8 per cent less likely to die than the matched patient controls.
Fluoxetine is often used to treat depression, and also sometimes obsessive compulsive disorder and bulimia, and fluvoxamine is used to treat obsessive-compulsive disorders and depression. While fluvoxamine is widely available, it is not on the World Health Organisation's Essential Medicines List. Fluoxetine, on the other hand, is on this list.
Though the effects are smaller than those found in recent clinical trials of new antivirals developed by Pfizer and Merck, the researchers said more treatment options are still needed to help bring the pandemic to an end.
"The results are encouraging," said Tomiko Oskotsky, a research scientist in Sirota's lab.
"It's important to find as many options as possible for treating any condition. A particular drug or treatment may not work or be well tolerated by everyone. Data from electronic medical records allow us to quickly look into existing drugs that could be repurposed for treating Covid-19 or other conditions," Oskotsky added.