A perfect broad-spectrum antiviral target. Montelukast, an anti-asthmatic candidate is actually a well-researched drug getting a higher affinity for the 3CLpro cleavage site. It was investigated to suppress oxidative strain. It has been hypothesized that the intake of high doses of montelukast has been advantageous in inflammatory disease (Asthma) (Fidan and Aydo du, 2020). As g the elevation in mortality is because of the elicitation of excess inflammatory responses, hence in response to such adverse clinical conditions montelukast may be investigated further to limit the wild illness progression. As compared to placebo, currently investigation on this anti-allergic agent has reached phase III clinical trial (Chams et al., 2020). Some other drugs possessing an affinity for 3CLpro are lymecycline, demeclocycline, and cIAP-2 Biological Activity doxycycline (antibacterial drugs), nicardipine, and telmisartan (antihypertensive drugs), and conivaptan, a nonpeptide inhibitor of vasopressin treating hyponatremia, showed high binding affinity to 3CLpro.Lopinavir/RitonavirLopinavir (Caspase 6 Compound ABT-378) is an antiviral medication that retains inhibitory activity against kind I aspartyl protease in human immunodeficiency virus-1 (HIV-1) (Ito et al., 2020). Ritonavir in mixture with lopinavir enhances (“boosts”) the plasma half-life, concentration, and antiviral mechanism from the latter by inhibiting cytochrome P450 and is hence generally employed as combination therapy to assist manage HIV infection (Perry et al., 2005). The trade name from the protease inhibitor mixture isInhibiting 3CLpro3CLpro, a cysteine protease also called C30 endopeptidase particularly cleaves SARS-CoV-2 poly-proteins at 11 web sites at CTD to elicit Nsps4 to Nsps16. 3CLpro promotes the maturation of vital Nsps, necessary inside the regulation of your virion life cycle. According to theoretical proof, the lopinavir/ritonavir mixture selectively inactivates the 3CLpro protease ofFrontiers in Pharmacology | www.frontiersin.orgFebruary 2021 | Volume 11 | ArticleDash et al.COVID-19 Interventions and Vaccine StrategyKaletraTM (Tobaiqy et al., 2020), which possesses a broad spectrum in vitro anticoronaviral method against SARS-CoV and MERS-CoV in vitro (McKee et al., 2020). A clinical case study revealed that lopinavir may ameliorate COVID-19 complications (Liu et al., 2020b). Indeed, the lopinavir/ ritonavir drug regimen progressively displayed very good clinical outcomes inside a COVID-19 patient in Korea by a synergistic reduction in viral load effect (Lim et al., 2020). A retrospective cohort study further supported that lopinavir monotherapy is definitely an exceptional medication to alleviate the spread of COVID-19 (Yao et al., 2020a). Having said that, an open-label, randomized clinical trial study (NCT04252885) employing a lopinavir/ ritonavir-based regimen displayed no important clinical improvement in coronavirus pneumonia sufferers (Cao et al., 2020). Similarly, Cao et al., reported a further randomized clinical trial (ChiCTR2000029308) executed on COVID-19 patients reported no substantial improvement in clinical outcomes right after administration of mixture therapy (lopinavir/ritonavir) when compared with standard of care (Cao et al., 2020). Subsequently, Baden and colleagues reported findings from a therapeutic study; the outcomes suggested that the larger lopinavir/ritonavir concentration may be essential to perturb SARS-CoV-2 RNA replication inside the lungs compared to the serum level (Baden and Rubin, 2020). Additionally, Yamamoto et al., reported that nelfinavir (trad.