**9. Closing Remarks**

Drug repurposing is an attractive proposition, since it involves the use of derisked and previously approved compounds, with lower development costs and shorter development times [209]. Since the onset of the COVID-19 pandemic, we have witnessed a plethora of alternative drugs as potential therapeutic avenues to fight the disease. Thus, hemin, a previously FDA and EMA approved drug for acute intermittent porphyria treatment, rises as a promising drug candidate, inducing HO-1 plasma concentration in humans, and posing a host defense advantage to fight SARS-CoV-2. Further work on optimal drug concentrations, pharmacokinetics and pharmacodynamics should be performed in order to prove hemin's effectiveness (either alone or in combination with other drugs) to halt infection.

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**Funding:** This work was supported by a grant from AGENCIA-PICT-2019-03215 (ARGENTINA).

**Acknowledgments:** We thank Javier Cotignola for his helpful comments and critical revision of this article.

**Conflicts of Interest:** The authors declare no conflict of interest.
