Hypoxemia in
COVID-19 pneumonia is associated with hospitalization,
mechanical ventilation, and mortality.
COVID-19 patients exhibit marked increases in
fatty acid levels and inflammatory
lipid mediators, predominantly
arachidonic acid metabolites, notably
thromboxane B2 >>
prostaglandin E2 >
prostaglandin D2.
Thromboxane A2 increases pulmonary capillary pressure and microvascular permeability, leading to
pulmonary edema, and causes bronchoconstriction contributing to ventilation/perfusion mismatch.
Prostaglandin D2-stimulated
IL-13 production is associated with
respiratory failure, possibly due to
hyaluronan accumulation in the lungs.
Ramatroban is an orally bioavailable, dual
thromboxane A2/TP and
prostaglandin D2/DP2 receptor antagonist used in Japan for
allergic rhinitis. Four consecutive outpatients with
COVID-19 pneumonia treated with
ramatroban exhibited rapid relief of
dyspnea and
hypoxemia within 12-36 h and complete resolution over 5 days, thereby avoiding hospitalization. Therefore,
ramatroban as an antivasospastic, broncho-relaxant, antithrombotic, and immunomodulatory agent merits study in randomized clinical trials that might offer hope for a cost-effective pandemic treatment.