Many drugs have been considered for treatment of Covid-19 and several monoclonal antibodies have been granted emergency use authorization by the FDA. However, the only FDA approved drug for treating Covid-19 is the IV antiviral Remdesivir that inhibits RNA polymerase.
Fluvoxamine is one of many SSRI’s (Selective Serotonin Reuptake Inhibitors) that are used to treat anxiety and depression. However, Fluvoxamine is structurally unrelated to the other SSRI’s. In addition to its serotonin modulating activity, it is a strong agonist (stimulator) of sigma-1 receptors in the endoplasmic reticulum.
Sigma-1 receptor stimulation has been shown to limit SARS-COV-2 replication and to modulate the inflammatory response to sepsis in animals. It is the overwhelming inflammatory response called cytokine storm that causes the life threatening acute respiratory distress syndrome in Covid-19.
So far, two very small studies in humans have been very promising. In a double-blind study of 152 people with Covid-19, ½ received fluvoxamine and ½ placebo. Clinical deterioration occurred in none of the fluvoxamine recipients whereas 6 of the placebo group deteriorated.
A second non-placebo-controlled study was done in 113 people with Covid-19. The participants were free to choose taking the medicine or not. Of the fluvoxamine receivers (65 in number) all were well after two weeks. In those not accepting the drug (48 in number) six were hospitalized, two were on ventilators and one died.
Now these are very small trials, so good science requires expanded studies. Right now, there is a large placebo-controlled trial under way which should be completed by September.