The threat due to the global pandemic of the coronavirus disease 2019 (COVID-19) demands a search for effective treatments to combat the severity of the infections and their associated morbidity and mortality in vulnerable populations. One of the medications with putative antiviral, anti-inflammatory, and immunomodulatory effects is fluvoxamine, a selective serotonin reuptake inhibitor and σ-1 receptor agonist. A few studies have reported doses of 100–300 mg/day to be effective.

This retrospective study evaluates the outcomes of an individually tailored dosing strategy for fluvoxamine, based on measurements of inflammatory status, in treating COVID-19-positive individuals in India.

This study included patients with severe acute respiratory syndrome coronavirus 2 infection visiting the outpatient department of a super speciality hospital in India from February to July 2021. Fluvoxamine was initiated at 50 mg or 100 mg twice daily based on their individual C-reactive protein (CRP) and D-dimer status. By day five, patients with rising or static levels of CRP and D-dimer were up-titrated.

In a population of 104 individuals infected with COVID-19, 10 required up-titration of dose, and 94 patients did not need up-titration. Overall, there was very low mortality (N = 1) and hospitalization rate (8.7%). Those individuals who required an up-titration on day five had significantly elevated CRP and D-dimer levels compared to those who were maintained at the initial dose of 50 mg twice daily. In such patients, up-titration of the dose on day 5 appeared to offer better treatment benefits and outcomes. In our study population, there was only one mortality during the course of COVID-19.

Given the individual variability in the host immune response to severe acute respiratory syndrome coronavirus 2 infection, tailoring the dose of a drug such as fluvoxamine based on the inflammatory status of the individual may be beneficial. Individually tailored dosing could combat disease progression while reducing side effects.