HTR2A and blood coagulation disease: As prophylactic anticoagulants such as heparin are administered to prevent COVID-19 associated coagulopathy [24], it would be useful to know if conventional anticoagulants targeting 5-HT2A antagonists such as sarpogrelate or cyproheptadine or antagonists of 5-HT2 receptors could be employed for reducing the hyper-coagulability complication in COVID-19 [25].