Dazoxiben, a thromboxane synthetase inhibitor, in the treatment of Raynaud's syndrome: a double-blind trial.

1 UK-37248 (dazoxiben), an orally active thromboxane synthetase inhibitor, was evaluated in a double-blind trial of patients with severe Raynaud's syndrome. 2 Twenty patients were enrolled in the study. Eleven of these patients received dazoxiben 400 mg day and nine received matching placebo capsules. Treatment was given for 6 weeks and the patients reviewed at 2 weekly intervals during the study. 3 Assessment of response was judged by clinical symptoms and hand temperature measurements. Haematological and haemostatic studies were also carried out. 4 Results show a significant clinical improvement in patients receiving dazoxiben for six weeks. Hand temperature measurements, and haematological and haemostatic blood tests remained unchanged, however, apart from the expected lowering in plasma thromboxane B2 levels. 5 The mechanism of action of the drug would appear not to be mediated through increased prostacyclin production and further studies are under way to determine how improvement has been obtained in these patients.