Lack of effect of pentoxifylline on red blood cell deformability.

The proposed mechanism of action for pentoxifylline's beneficial effect in peripheral vascular disease is an improvement in red blood cell deformability. Likewise, single doses of pentoxifylline in healthy volunteers have been shown to improve whole blood filterability, which was suggested to occur as a result of augmented red blood cell deformability. To further assess this, the authors studied the effects of short-term pentoxifylline administration (400 mg three times daily for 7 days) on red blood cell deformability in ten healthy, methylxanthine-free, nonsmoking volunteers. Blood samples were obtained at baseline and after 1 week of therapy (steady-state). Samples were analyzed for red blood cell deformability by ektacytometry, which showed no significant change in deformability in any subject. Despite the improvement in whole blood filterability associated with both single-dose and short-term administration of pentoxifylline, the current study demonstrates no effect on red blood cell deformability after short-term administration in healthy volunteers.