Pentoxifylline: An Immunomodulatory Drug for the Treatment of COVID-19

Rapidly spreading outbreak of the novel Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is causing serious health concerns worldwide. It started as an epidemic in Wuhan, Hubei province, central China, and has now become a pandemic, spreading over most of the continents of the planet. The major clinical symptoms of the infection are dry cough, fever, pneumonia, respiratory failure, hypoxia, and in certain cases, even death. Alveolar damage and respiratory system failure are observed in severe cases. Initial mild infection leads to activation of the immune system in the lungs and accumulation of various inflammatory cells and molecules. At a later phase during the infection, a "cytokine storm" causes an Acute Respiratory Distress Syndrome (ARDS), leading to an increase in the production of pro-inflammatory cytokines, migration of a large number of immune cells to the site of infection, and ultimately pulmonary damage. The rapid and uncontrolled outbreak requires putative therapeutic drugs for treatment of patients suffering from COVID-19. Amongst the currently used antiviral drugs, such as hydroxychloroquine, lopinavir, remdesivir etc. we would like to present an update on another effective drug, pentoxifylline. Pentoxifylline has anti-inflammatory, immunomodulatory, anti-viral, and bronchodilatory properties. Pentoxifylline is known to reduce cytokine production, immune cell migration, and suppress certain signal transduction pathways (e.g. NF-kappa beta and STAT3). Thus, it minimizes inflammatory damage in the lung tissues.