Abstract
1 Blood viscosity is thought to be a major factor in disorders of the peripheral circulation. 2 Ten patients with obliterative arterial disease received an infusion of isoxsuprine of 20 micrograms kg-1 for 30 min. The infusion was followed by a highly significant and prolonged fall in blood, plasma and serum viscosity, in haematocrit and in plasma fibrinogen concentration. Blood lipid levels were also studied: total lipids and total cholesterol did not alter; triglyceride level was significantly lowered at the end of, and after, drug infusion. 3 There was no change in blood, plasma or serum viscosity in the four patients receiving a control infusion 2 days before the infusion of isoxsuprine. 4 The relationships between lowered viscosity and increasing peripheral tissue perfusion are discussed.