Dazoxiben is a selective inhibitor of thromboxane synthetase (IC50 3 nM), an enzyme that converts the endo-peroxide PGH2 into thromboxane A2, which is a potent vasoconstrictor and platelet aggregating agent. Dazoxiben has demonstrated efficacy in some clinical trial for the treatment of Raynaud's syndrome, an ischaemic condition manifested by the pallor of affected digits. In subsequent studies, however, no significant effect of dazoxiben was found. Dazoxiben was also evaluated in patients with sepsis, adult respiratory distress syndrome, stable angina, and other conditions.