Abstract
Respiratory tract infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) first occurred in Wuhan, China, in December 2019 and was declared as a pandemic by WHO. The interaction between the 2019 coronavirus disease (COVID-19) and pulmonary hypertension (PH) in children is not widely known. Phosphodiesterase-5 inhibitors (PDEI), one class of drugs used to treat PH, including sildenafil, can suppress angiotensin type I (AT-1) receptor expression. Furthermore, it reduces proinflammatory cytokines and infiltrates the alveolar, inhibits endothelial and smooth muscle transition, mesenchymal cells in the pulmonary artery, and prevents clotting and thrombosis complications. Sildenafil has shown positive effects by diverting the blood flow to the lungs in such a way that ventilation is adequate and can also be anti-inflammatory.