Our data provide a proof-of-concept for the potential feasibility of repurposing of FDA approved non-peptide opioid antagonist; naltrexone as host-targeted broad-spectrum antiviral therapies to combat COVID-19 infections. The next step will be to confirm data in COVID-19 patients. LDN alone or as an adjuvant therapy with hydroxychloroquine or an antiviral agent may give physicians more time to provide supportive treatment for patients with COVID-19.