**2.15 Other miscellaneous drugs with a possible therapeutic effect**

In the pathogenesis of Covid-19, ACE 2 receptors play an important role by facilitating the entry of the virus into the cell [1, 95]. Thus it could be a possible therapeutic target with the use of ACE-inhibitors and ARB [1, 96]. However, there is a concern that the use of these drugs to stop virus replication may increase the expression of ACE-2 receptors and paradoxically worsen the infection. However, no in-vitro studies are available which show either definite detrimental or protective effect of these agents. As a result, the current guidelines state to continue these drugs in patients who are already taking them [97].

Umifenovir (also known as Arbidol) is an antiviral agent with a unique mechanism of action targeting the S protein/ACE2 interaction and inhibiting membrane fusion of the viral envelope [98]. It is approved in Russia for prophylaxis and treatment of influenza. Of particular interest is its demonstrable in-vitro activity against Covid-19 [99]. In an observational study in China, patients treated with umifenovir for a median duration of 9 days had a higher discharge rate and lesser mortality [100]. But as with other agents, the lack of RCT limits the justification for its use in Covid-19. However, ACE targeting therapy is a promising one [1].

Camostat mesylate is an agent used in the treatment of pancreatitis. It inhibits host serine protease, TMPRSS2.3, and has been shown to prevent viral cell entry in-vitro and thus could be a target for future studies [101].

Nitazoxanide, an anti-helminthic with a relatively favorable safety profile has shown in-vitro activity against SARS-CoV and MERS [102]. Besides it also has additional immunomodulatory action & thus can be used in trials in Covid-19 patients as a therapeutic option.

Many non-allopathic pharmaceuticals are also in pipeline as promising COVID-19 therapy. In June 2020, yoga guru Baba Ramdev announced that his company Patanjali Ayurved had launched a drug called 'Coronil' that could cure COVID-19 [103]. However, no scientific basis for this claim is produced until now.
