Effects of oral and intravenous defibrotide on blood viscosity in patients with peripheral obliterative arterial disease.

Patients with peripheral obliterative arterial disease received 400 mg of defibrotide intravenously (seven patients) or orally (nine patients). Blood and plasma viscosity were measured before therapy, at 30 minutes after and one hour after intravenous administration, and at 1, 2, 3, and 8 hours after oral administration. Thirty minutes after intravenous administration, blood viscosity at a shear rate of 30 sec-1 was reduced from 9.99 to 9.00 and at a shear rate of 180 sec-1 from 6.61 to 6.33 (P less than 0.05). Viscosity returned to baseline after 60 minutes. At 1, 2, and 3 hours after oral administration, blood viscosity at a shear rate of 30 sec-1 was reduced from 8.53 to 7.44, 6.88, and 7.19 (each P less than 0.01) and at a shear rate of 180 sec-1 from 5.88 to 5.51 (P less than 0.05), 5.14 (P less than 0.05), and 5.38 (P less than 0.01); the levels at eight hours were not significantly different from baseline values. Plasma viscosity was not affected by defibrotide. These data confirm previous evidence of a rheologic effect of defibrotide in patients with peripheral obliterative arterial disease and indicate that such an effect can be achieved with oral administration.