[Effect of hexobendine and pentoxifylline on the viscosity of erythrocyte suspension].

The effect of hexobendine, pentoxifylline and of the combination Instenon, containing hexobendine, on the dynamic viscosity of blood-isotonic and hyperosmolal suspensions of human and rat erythrocytes was studied. Hexobendine caused a statistically significant reduction of viscosity beginning at 10(-4) M, under hyperosmolal conditions even at 10(-5) M. Instenon was somewhat less active than hexobendine alone at a concentration equivalent to its presence in Instenon. Pentoxifylline did not decrease the viscosity under the selected conditions. The effect of hexobendine is considered due to an increase of red cell flexibility, probably caused by an elevation of the ATP content or by an alteration of the membrane structure of the erythrocytes.