The rationale for using fluvoxamine in the treatment of Covid patients.

Fluvoxamine is a selcetive serotonin reuptake inhibitor (SSRI)  & a potent σ-1 (S1R) receptor agonist The lung tissue damage caused by Covid results in an excessive immune response (also inflammatory) by the patient which further exacerbates a patient's condition.(Lenze et al.,2020:2292).

It has a anti-inflammatory effect & is therefore used to help Covid patients.Fluvoxamine binds to sigma-1 receptor in the immune cells of the body, reducing the production of inflammatory cytokines.

Stimulation of the stigma-1 receptor reduces the synthesis of pro-inflammatory cytokines, thereby reducing systemic inflammation.

References:

Lenze E.J,Mattar C.,Zorumski C.F.,Stevens,A.,Schweiger,J.,Nicol.G.E.,...Reiersen,A.M. 2020. Fluvoxamine vs Placebo and Clinical Deterioration in Outpatients With Symptomatic COVID-19: A Randomized Clinical Trail.

https://www.covid10treatmentguidlines.nih.gov/therapies/immunomodulators/fluvoxamine/#:~:text+Anti%2Dlnflammatory%2oEffect%2of%20fluvoxamine,reduced%20production%20of%20inflammatory%20cytokines