This is a randomized, randomized controlled trial to investigate the efficacy and safety of Neurokinin-1 Receptor (NK-1R) 80 mg orally given daily to treat cytokine storm causing inflammatory lung injury and respiratory failure associated with severe or critical COVID-19 infection. NK-1R is the receptor of Substance P (SP) and responsible for its functionality. Here, we propose that SP via its tachykinin receptor, NK-1R may cause inflammation in Covid-19 infection. It may initiate the cytokine storming via binding to its receptor NK-1 and many inflammatory mediators are released. If SP release is reduced by NK-1R antagonist, it may control the cytokine storming and hence the hyper-responsiveness of the respiratory tract through reduction in cytokine storming It may serve as the treatment strategy for Covid-19 infected patients. Patients fulfilling the inclusion criteria will be enrolled after giving consent. They wll be randomized to treatment with either NK-1R antagonist or placebo in addition to Dexamethasone as a standard treatment given to both groups for Covid-19 infection as per the protocol at the treating hospital. Inflammatory lab markers as detailed should be collected once per day in the morning, preferably at the same time every morning. All enrolled participants will have whole blood collected for whole genome sequencing.