In one hand, indomethacin is a synthetic, small molecule of N-benzoyl-indole-3-acetic acid derivative (Figure 7). It was first approved by the U.S. FDA in 1984 for use as NSAID. It also possesses analgesic and antipyretic properties. It is used for acute mild to moderate pain. It is also used for ankylosing spondylitis, bursitis, tendonitis, osteoarthritis, and rheumatoid arthritis, among other conditions. The known mechanism is the reversible inhibition of cyclooxygenase-1 and 2 enzymes, which leads to decreased formation of prostaglandin precursors [142]. Orally administered indomethacin is being evaluated in combination with hydroxychloroquine and azithromycin in an open-label, single-arm, phase 2 study to determine its efficacy and safety in subjects with mild COVID-19 symptoms (NCT04344457; n = 80).