Table 2.

Details of various repurposed drugs in COVID-19 infection.

Class of drugs		Drugs	Mechanism of action	References
Antivirals		Remdesivir	Inhibitor of RNA-dependent RNA polymerase and, hence, compete for viral ATP, which results in inhibition of viral replication	Young et al., 2021
		Lopinavir/ritonavir	Inhibitor of 3-chymotrypsin-like protease (3CLpro) and inhibit viral replication	Cao et al., 2020
		Ivermectin	Blocker importin α/β receptor and, hence, inhibit the transmission of viral protein into the nucleus of host cell	Caly et al., 2020
		Ribavirin	Potent inhibitor of viral RNA synthesis	Iqubal et al., 2021b
		Favipiravir	Inhibitor of RNA-dependent RNA polymerase and, hence, compete for viral ATP, which results in inhibition of viral replication	Iqubal et al., 2021b
		Umifenovir	Affects the S protein activity and, hence, inhibit its fusion with the host cell	Iqubal et al., 2021b
Immunomodulators		Corticosteroids Dexamethasone Hydrocortisone Methylprednisolone	Effectively mitigate the pro-inflammatory signaling pathways, stimulate the anti-inflammatory pathways, inhibit COX as well as NF-kB-mediated hyperinflammation, and, hence, reduce the cytokine storm	Hamilton et al., 2021
		IFN β-1a	Potentiate the interferon and assist in viral clearance	Davoudi-Monfared et al., 2020
		IL-6R-antagonists Tocilizumab Sarilumab	Inhibit IL-6-mediated hyperinflammation and cytokine storm	Michot et al., 2020; Gordon et al., 2021
		IL-1R antagonists Anakinra
		TNF-α inhibitors Adalimumab	Inhibit TNF-α-mediated hyperinflammation and control cytokine storm	Iqubal et al., 2021a
		Bruton’s tyrosine kinase inhibitors Ibrutinib Rilzabrutinib Acalabrutinib	Potent inhibitor of TLR-4 activation and, therefore, mitigate the cytokine storm and inflammatory pathway	Roschewski et al., 2020
		JAK inhibitors Baricitinib Fedratinib	Inhibit JAK and activate STAT pathway, leading to inhibition of cytokine production and maturation. Additionally, these drugs inhibit the viral endocytosis via interacting with ACE2	Stebbing et al., 2020
		Calcineurin inhibitors * Cyclosporine * Tacrolimus	Reduced the production of T-lymphocytes via tumbling the expression of IL-2 receptor and production of IL-2. Inhibit the viral replication	Cavagna et al., 2020
Complement inhibitors		Eculizumab	Inhibit the production of inflammatory C5a and C5b-9	Laurence et al., 2020
Kinin–kallikrein pathway inhibitors		Lanadelumab	Inhibitor of kallikrein and hence offers relief from ARDS	Lipcsey et al., 2021
		Icatibant	Antagonist of bradykinin receptor type 2 and thus, inhibit hyperinflammation
Serine protease inhibitors		C1 esterase inhibitor Camostat mesylate Nafamostat mesylate	Inhibit the coagulation and ARDS via interacting with FXIIa and kallikrein	Urwyler et al., 2020
Antimalarials		Hydroxychloroquine	Inhibit the viral entry, replication, cytokine production and coagulation	Mitjà et al., 2021
		Chloroquine
Blood-derived products		Convalescent plasma	Maintain and stimulate the physiological defense against viral infection	Iqubal et al., 2021c
		Hyperimmune immunoglobulin
		Bamlanivimab	Anti-spike neutralizing IgG1 monoclonal antibody that interferes with the function of viral spike proteins	Gottlieb et al., 2021
		REGN-COV2 Casirivimab Bamlanivimab Imdevimab Etesevimab Sotrovimab	Cocktail of two anti-spike neutralizing antibodies that that interfere the function of viral spike proteins	Tardif et al., 2021
Miscellaneous	Colchicine		Reduce hyperinflammation	Tardif et al., 2021
	Vitamin D		Maintain the immune function (innate and adaptive immune system). Reduce oxidative stress, inflammation and scavenge free radicals.	Giannini et al., 2021
	Azithromycin		Assist in viral clearance and inhibit viral replication.	Oldenburg and Doan, 2020
	Sirolimus		Inhibit T-cell differentiation via inhibiting mTOR pathway and, hence, reduces cytokine storm and ARDS.	Omarjee et al., 2020
	Bevacizumab		Inhibition of IL-6 and hence reduces the severity of cytokine storm and ARDS	Pang et al., 2021

COVID-19, coronavirus disease 2019; ARDS, acute respiratory distress syndrome.