By Marisa Iati and Adela Suliman
Washington - A common antidepressant medication often used to treat obsessive compulsive disorder may join a growing arsenal of Covid-19 treatments after it showed promise in reducing hospitalizations and deaths from the disease caused by the novel coronavirus.
Because it has already been approved for mental health treatment, doctors can begin to prescribe it under certain parameters. The relatively modest cost means it could be highly beneficial in parts of the world with low vaccination rates and few resources.
Here's what you need to know.
What is fluvoxamine?
Fluvoxamine, which is produced by several manufacturers, is generally used to reduce repetitive, unwanted thoughts and ritualized behaviours. It can also be prescribed off-label for major depressive disorder, post-traumatic stress disorder, eating disorders and other conditions.
In use since the 1990s, the drug is a selective serotonin reuptake inhibitor that helps restore the balance of serotonin in the brain. Researchers said they decided to study its possible use in treating Covid-19 because of its anti-inflammatory and possibly anti-viral properties. It was also identified early in the pandemic as capable of reducing what's known as cytokine storms, in which the body attacks healthy cells and tissues.
The study, published on Wednesday in the Lancet journal, found that giving high-risk Covid-19 patients fluvoxamine - 100 mg twice daily for 10 days - early in their treatment reduced the need for hospitalization.
The clinical trial took place from January to August and included roughly 1 500 people at 11 sites in Brazil. The participants were adults who were symptomatic with Covid-19 and at heightened risk of severe illness because of other health problems. Their average age was 50, almost 60% were women, and most self-identified as mixed race.
About half of the participants received fluvoxamine, while the other half got a placebo. They took their pills for 10 days at home, and scientists tracked them for four weeks.
In the group that took fluvoxamine, 11% needed hospitalization or an extended emergency room stay, compared with 16% of those who got the placebo.
"For every 20 people in this population you treated, you'd cause benefit for one person, basically," said David Boulware, a professor of medicine at the University of Minnesota who worked on a smaller study of the drug. "That's a pretty darn good number, particularly for outpatient settings for early Covid."
Among participants who were 80% adherent to the treatment regimen, one person who got fluvoxamine died, compared with 12 who received a placebo.
Angela Reiersen, a psychiatrist at Washington University in St. Louis who originally came up with the idea to study fluvoxamine for Covid-19, called the findings "pretty remarkable."
"I think this is enough to convince many physicians to prescribe fluvoxamine for some patients who are early in the course of Covid-19, especially for individuals who have a lot of risk factors," she said.
The drug has also shown positive results against Covid-19 in smaller studies.
What are the possible side effects?
Common side effects of fluvoxamine include headaches, nausea, diarrhoea and dizziness, according to the National Alliance on Mental Illness. Some patients have also reported problems with orgasm or ejaculatory delay. NAMI says these problems will often improve as patients keep taking the medication, with the exception of sexual side effects. In rare cases, fluvoxamine can cause low sodium blood levels, seizures, bleeding and other conditions.
The researchers said questions remain about fluvoxamine's tolerability, as several participants receiving the drug stopped taking it because of side effects. Two ongoing trials - one funded by the National Institutes of Health and another at the University of Minnesota - are examining the use of a lower dose in Covid-19 patients.
People taking fluvoxamine are advised to avoid alcohol or illegal drugs, which can make fluvoxamine less effective and increase side effects. Patients should also limit their coffee intake, since the drug extends the effects of caffeine, Boulware said.
Fluvoxamine interacts with several other medications, so patients should talk with their doctors about what other drugs they take. People who are pregnant or breastfeeding should also consult their physicians.
When will it be available to treat Covid-19?
Because fluvoxamine is approved by the Food and Drug Administration as an antidepressant, doctors already can prescribe it off-label - using their clinical judgment - to treat Covid-19.
The drug is given as a pill and is relatively inexpensive, costing about $4 (about R60) for a 10-day course, compared with antibody IV treatments that cost about $2,000 and Merck's $700-per-course antiviral pill. Study co-author Edward Mills, of McMaster University in Ontario, said fluvoxamine's cost efficiency could make it a "game-changer" for poorer nations or those with low vaccination rates.
Since most participants in the trial were unvaccinated, the researchers wrote that further evidence was needed to establish its benefit in vaccinated people. Reiersen said she would also be interested in whether fluvoxamine could be effectively combined with other covid-19 treatments.
The Together Trial group, which was responsible for the new research, said it had shared its findings with the World Health Organization and NIH, which publishes treatment guidelines. The FDA does not have to reapprove the drug.
"Given fluvoxamine's safety, tolerability, ease of use, low cost, and widespread availability, these findings might influence national and international guidelines on the clinical management of mill," the researchers wrote.
How is fluvoxamine different from other Covid-19 drugs?
Fluvoxamine is a familiar drug that has been used for more than two decades and is known to be safe. It and Merck's drug, molnupiravir, are also distinct from other Covid-19 treatments because they can be given as pills and taken at home. Both medications are meant to be started soon after diagnosis.
By contrast, other treatments are harder to administer. Monoclonal antibodies are infused or injected, and medical experts say the treatment is expensive and difficult to deliver. In the new trial, fluvoxamine proved about equally successful at reducing hospitalizations as monoclonal antibodies when taken as prescribed, Boulware said.
Remdesivir is also injected, and while it has been shown to shorten hospital visits, its ability to reduce severe illness and death is unclear. Dexamethasone, a steroid, is frequently used in hospitalized patients who are on ventilators or receiving supplemental oxygen.
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